THE TEXTILE FIBRES j THEIR PHYSICAL, MICROSCOPICAL AND CHEMICAL PROPERTIES BY J. MERRITT MATTHEWS, PH.D. / / Head of Chemical and Dyeing Department Philadelphia Textile School SECOND EDITION, REWRITTEN FIRST THOUSAND NEW YORK JOHN WILEY & SONS LONDON: CHAPMAN & HALL, LIMITED 1907 c Copyright, 1904, 1907 liY J. MERRITT MATTHEWS ROBERT DRUMMOND, PRINTER, NKW YORK PREFACE. THE present book, it is hoped, will be of assistance to both the practical operator in textiles and the student on textile subjects. It has been the outgrowth of a number of years of experience in the teaching of textile chemistry, as well as prac- tical observation in the many mill problems which have come under the notice of the author. The textile fibres form the raw materials for many of our greatest industries, and hence it is of importance that the facts concerning them should be systematized into some form of scientific knowledge. The author has attempted, however, not to allow the purely scientific phase of the subject to overbalance the practical bearing of such knowledge on the every-day problems of industry. Heretofore, the literature on the textile fibres has been chiefly confined to a chapter or two in general treatises on dyeing or other textile subjects, or to specialized books such as Hohnel's work on the microscopy of the fibres. It has been the author's endeavor, in the present volume, to bring together, as far as possible, all of the material available for the study of the textile fibres. Such material is as yet incomplete and rather poorly organized at its best ; but it is hoped that this volume may prove a stimulus along the several lines of research which are available in this field. Unfortunately, the subject of the textile fibres has been lamentably neglected by chemists, although there is abundant indication that a fertile field of research is open to chemists in this direction, and such work would have not only iii iv PREFACE. a scientific value, but might also lead to great industrial worth. There is, as yet, relatively little known concerning the chemical constituents of the fibres, and the manner in which varying chemical conditions affect the composition and properties of these constituents. The action of various chemical agents on the fibre as an individual has been but very imperfectly studied. More work has been done in the microscopical field concerning the properties of the fibres; but even here the knowledge is very incomplete and disjointed, and especial attention is drawn to the fact there is yet a large amount of work to be done in the microchemistry of the subject. The author has endeavored to emphasize throughout this volume the importance of the study of the fibre as an individual, for in many cases it is misleading to assume that the behavior of the individual fibre is identical with that of a large mass of fibres in the form of yarn or cloth. In the latter case, the dif- ference in physical condition and the action of mechanical forces has an important influence. By going back to the study of the individual fibre as a basis, many explanations can be given which could not be discovered otherwise. It is hoped that this book may afford instruction both to the manufacturer and to the student; assisting the former in solving some of the many practical problems constantly occurring in the manufacture of textiles, and urging the latter on to an increased effort in the scientific development of the subject. J. MERRITT MATTHEWS. PHILADELPHIA TEXTILE SCHOOL, January, 1907. CONTENTS. CHAPTER I. CLASSIFICATION OF THE TEXTILE FIBRES. FACE 1 . Fibres Chiefly Used for Textiles I 2. Animal and Vegetable Fibres i 3. Mineral and Artificial Fibres 4 CHAPTER II. WOOL AND HAIR FIBRES. 1 . The Sheep 8 2. Physiology and Structure of Wool 13 CHAPTER III. THE CHEMICAL NATURE AND PROPERTIES OF WOOL AND HAIR FIBRES. 1. Chemical Constitution 33 2 . Chemical Reactions 41 3. Microchemical Reactions 51 4. Hygroscopic Quality 52 5. Conditioning of Wool 53 CHAPTER IV. SHODDY AND WOOL SUBSTITUTES. 1 . Varieties of Shoddy 70 2. Examination of Shoddy 71 CHAPTER V. MINOR HAIR FIBRES. 1. The Minor Hair Fibres 75 2. Mohair 75 3. Cashmere 77 v vi CONTENTS. PAGE 4. Alpaca 79 5. Vicuna Wool 81 6. Llama Fibre 82 7 . Camel-hair 83 8. Cow-hair 85 9. Minor Hair Fibres 87 CHAPTER VI. SILK: ITS ORIGIN AND CULTIVATION. 1 . General Considerations 91 2. The Silkworm 91 3. Diseases of the Silkworm 99 4. Wild Silks '. 101 5. The Microscopical and Physical Properties of Silk 103 6. Silk-reeling no 7 . Determination of Size of Silk Yarns 112 CHAPTER VII. CHEMICAL NATURE AND PROPERTIES OF SILK. 1 . Chemical Constitution. . 116 2 . Chemical Reactions 123 CHAPTER VIII. THE VEGETABLE FIBRES. 1 . General Considerations 130 2 . Classification 134 3. Physical Structure and Properties 144 4. Chemical Composition and Properties 149 5. Chemical Investigation of Vegetable Fibres 154 CHAPTER IX. COTTON. 1 . Historical 157 2 . Origin and Growth 1 60 ^. Varieties of Cotton 172 CHAPTER X. THE PHYSICAL STRUCTURE AND PROPERTIES OF COTTON. 1 . Physical Structure 186 2. Microscopical Properties 200 3. Physical Properties 203 4. Hygroscopic Quality 206 CONTENTS vii CHAPTER XI. CHEMICAL PROPERTIES OF COTTON; CELLULOSE. PAGE 1 . Chemical Constitution 209 2 . Cellulose 213 3. Chemical Reactions of Cotton 222 CHAPTER XII. MERCERIZED COTTON. 1 . Mercerizing 234 2 . Conditions of Mercerizing 239 3. Properties of Mercerized Cotton 245 CHAPTER XIII. SEED-HAIRS OTHER THAN COTTON. 1 . Bombax Cotton i . . . . 249 2 . Vegetable Silk 252 CHAPTER XIV. ARTIFICIAL SILKS; LUSTRA-CELLULOSE. i. General Considerations 255 Vr-2. Chardonnet Silk 256 3 . Du Vivier's Silk 260. 4. Lehner's Silk 261 5. Cuprammonium Silk 262 6. Viscose Silk 263 7. Properties of Lustra-cellulose 265 8. Vanduara Silk 267 9. Comparison of Artificial Silks 268 10. Animalized Cotton 27*0 CHAPTER XV. LINEN. 1 . Preparation 271 2. Chemical and Physical Properties 278 CHAPTER XVI. JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 1 . Jute 284 2. Ramie or China Grass 291 3- Hemp r 297 4. Sunn Hemp 306 5. Ambari or Gambo Hemp 308 6. New Zealand Flax 310 7. Manila Hemp 313 viii CONTENTS. PAGE 8. Sisal Hemp 316 9. Aloe Fibre or Mauritius Hemp. 318 10. Pita Fibre 320 1 1 . Pineapple Fibre or Silk Grass 323 12. Coir Fibre 324 13. Istle Fibre 326 14. Nettle Fibre 326 15. Fibre of Urena Sinuata 328 16. Sansevieria Fibres 329 17. Fibre of Sea Grass 330 18. Raphia 330 19. Bromelia Fibres 331 CHAPTER XVII. QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 1 . Fibres to be Considered 334 2 . Qualitative Tests 335 3. Distinction between Cotton and Linen 342 4. Distinction between New Zealand Flax, Jute, Hemp, and Linen . 346 5. Ligneous Matter 349 6. Reactions of Bast Fibres 349 7. Systematic Analysis of Mixed Fibres 349 8. Identification of Artificial Silks 350 9. Distinction between True Silk and Different Varieties of Wild Silk 350 10. Micro-analytical Tables 355 CHAPTER XVIII. QUANTITATIVE ANALYSIS OF THE TEXTILE FIBRES. 1 . Wool and Cotton Fabrics 378 2. Wool and Silk 383 3. Silk and Cotton 384 4. Wool, Cotton, and Silk 385 5. Analysis of Weighting in Silk Fabrics 39^ 6. Oil and Grease in Yarns and Fabrics 406 7. Estimation of Finishing Materials on Fabrics 40- 8. Testing the Water-proof Quality of Fabrics 40^ APPENDIX I. MICROSCOPIC ANALYSIS OF FABRICS 411 APPENDIX II. MACHINE FOR DETERMINING STRENGTH OF FIBRES 414 APPENDIX III. COMMERCIAL VARIETIES OF AMERICAN COTTON 417 APPENDIX IV. BIBLIOGRAPHY OF THE TEXTILE FIBRES 431 OF THE UNIVERSITY OF THE TEXTILE FIBRES, CHAPTER I. CLASSIFICATION OF THE TEXTILE FIBRES. 1. Fibres Chiefly Used for Textiles. In order to be service- able in a textile fabric, a fibre must possess sufficient length to be woven and a physical structure which will permit of several fibres being spun together, thereby yielding a continuous thread of considerable tensile strength and pliability. Although there are several fibres, such as spun glass, asbestos, various grasses, etc., which are used for the manufacture of textiles in peculiar and rare instances, yet the fibres which are employed to the greatest extent and which exhibit the most satisfactory qualities are wool, silk, cotton, and linen. All of these possess an organ- ized structure, and are the products of a natural growth in life processes. According to Georgevics, all textile fibres may be divided into four distinct classes; and though the same general arrange- ment is here preserved, the order has been somewhat changed so as to bring the most prominent ones first: (i) Animal fibres; (2) Vegetable fibres; (3) Mineral fibres; (4) Artificial fibres. 2. Animal and Vegetable Fibres. According to their origin, we may divide the principal fibres into two general classes, those derived from animal and those derived from vegetable life. The former includes wool and silk, and the latter cotton and linen. Animal fibres are essentially nitrogenous substances (protein 2 THE TEXTILE FIBRES. matter),* and in some cases contain sulphur. They may also be solid filaments formed from a liquid secretion of certain cater- pillars, spiders, or molluscs. Alkalies readily attack the animal fibres, causing them to be dissolved, but they withstand the action of mineral acids to a considerable degree. Contrary to the Par. s.s. M.L. Sd. Par - SdX p - H - FIG. i. Section of Vascular Bundle of Sisal Hemp. (X3oo.) Par, cellular parenchyma; S.S., starch layer; Scl, sclerenchyma; M.L., middle lamella; B.S., bundle sheath; X, xylem or wood cells; P.H., phloem or bast cells. (After Morris.) vegetable fibres, they are readily injured if exposed to elevated temperatures. Vegetable fibres consist of plant-cells,f usually * Protein matter is of the character of albumin, and forms one of the prin- cipal ingredients of animal tissues. It is essentially nitrogenous in composition and is especially characterized by the peculiar empyreumatic odor evolved when burned. One of the readiest and most conclusive tests, in fact, which may be used to distinguish between an animal and a vegetable fibre is to notice the odor evolved on burning in the air. With regard to their physical condition, it may be said the proteids composing the animal fibres are essentially of a. colloidal nature; that is, they resemble a solidified jelly in condition. This property of the fibres may be used, to a great extent, to explain their action with solutions of dyestuffs and metallic salts, in which the theory of solid solution and osmosis comes into play. f Plant -cells are of different character and size depending on the part of the CLASSIFICATION OF THE TEXTILE FIBRES. rather simple in structure and forming an integral part of the plant itself. They are capable of withstanding rather high temperatures, and are not weakened or disinte- grated by the action of dilute alkalies. They consist essentially of cellulose, which may be in a very pure form or be mixed with its various alteration products. In some cases the fibre consists of some cellulose derivative obtained by chemical means, such, for instance, as mercerized cotton. Concentrated alkalies produce alteration products with the vegetable fibres. Free sul- phuric or hydrochloric acid, even if only mod- erately strong, will quickly attack the fibre, disintegrating its organic structure and forming hydrolyzed products. Nitric acid, on the other hand, forms nitrated celluloses (the so-called FIG nitre-celluloses) and various oxidation derivatives, cells of Wood It is generally considered that the animal fibres Tissue. (XSQO.) have a lower conductivity for heat than have ^ Afte the vegetable fibres, and in consequence fabrics made from wool and silk are warmer than those made from cotton and linen.* plant in which they occur and the office or function they perform in the develop- ment of the plant tissue. These cells consist of tubes generally between o.ooi in. and 0.002 in. in diameter; their ends are usually pointed and in their arrange- ment overlap one another. (See Fig. 2.) In the fibrous layers occurring in plants these cells are sufficiently long and so interlaced as to give a fibre of considerable strength, whereas in plain woody tissue the cells are short and properly speak- ing yield no fibre of sufficient strength or length to be used for textile purposes. In monocotyledons, according to Dr. Morris, the fibrous cells are found buill up with vessels into a composite structure known as fibro-vascular bundles; these bundles occur in the leaves and stems, but not in the outer bark of plants (see Fig. i), and are usually found imbedded in a soft cellular tissue known as parenchyma. * Count Rumford made some interesting experiments relative to the K heat- retaining value'" &i various clothing materials. He heated a large thermometer to a given tempeflHrre and then ascertained the length of time required for the thermometer to fall to a given point when surrounded with the various mate- rials experimented upon. The times taken by the thermometer in falling from 4 THE TEXTILE FIBRES. 3. Mineral and Artificial Fibres. These two classes of fibres are of rare occurrence in the textile industry when compared with the extensive use of the preceding fibres. They find a lim- ited use, however, for certain purposes, and deserve to be con- sidered in a systematic study of the subject. The principal, and strictly speaking the only, mineral fibre is asbestos, which occurs in nature as the mineral of that name. It 'is a fibrous silicate of magnesium and calcium, though often containing iron and alumin- ium in its composition, especially in the dark-colored varieties.* This mineral, though in the form of a hard rock, can be easily separated into slender f white fibres (Fig. 3), sometimes inclining 70 to 10 Reaumur, when surrounded with various substances, were as follows: Seconds. Air. 576 Raw silk 1284 Sheep's wool 1 18 Cotton 1046 Fine lint 1032 Beaver's fur 1296 Hare's fur 1315 Eiderdown 1305 In another series of experiments, however, using the same materials differently arranged, very different results were obtained: Seconds. Sheep's wool, loosely arranged 1118 Woolen thread, wound round bulb 934 Cotton, loose 1046 Cotton thread, wound round bulb 852. Lint, loose 1032 Linen thread, wound round bulb 873 Linen cloth, ditto 786 From these experiments, Rumford showed that the heat-retaining value of clothing depends more on its texture than on its actual material. For further consideration of this subject, see Mattieu Williams' book on The Philosophy of Clothing. * The general term "asbestos" includes the fibrous varieties of both pyroxene and hornblende. Pyroxene is a compound silicate of magnesium and calcium, always containing iron, and generally also some manganese. Hornblende (also known as amphibole) is very similar in composition, but often contains alu- minium. ^^* fThe individual fibres of asbestos are so fine as to approach the limits of microscopic measurement which is ^=0.0005 mm. CLASSIFICATION OF THE TEXTILE FIBRES. 5 towards a greenish color. The fibres of some varieties (Canadian) are curly, and afford the best material for spinning.* In general, however, the fibres of asbestos are straight and glassy in structure, and are difficult to spin into a coherent thread. In order to enhance its spinning qualities it is mixed with a little cotton or linen, the latter fibre being subsequently destroyed by heating the woven fabric to incandescence. By improved methods of handling, however, it is now possible to spin asbestos directly without admixture with cotton; the asbestos is first softened FIG. 3. Asbestos Fibre. (X5-) (Micrograph by author.) in hot water and then disintegrated mechanically into the fibre. At the present time quite a variety of fabrics are manufactured from asbestos fibre, and the high quality of many articles appearing * Asbestos occurs in a variety of species, some of which are much more valu- able than others for fibre purposes. In some the fibres are slender and easily separable, and of a white or greenish color. A variety known as Amianthus gives fibres of a fine silky quality. Ligniform asbestos is a hard compact variety, resembling petrified wood in appearance, and brownish to yellowish in color; a wool-like variety found near Vesuvius is known as Breislakite. A variety of serpentine also yields an asbestos, but of inferior quality; it differs from the hornblende variety in that it contains about 14 per cent, of water in its com- position. The mineralogical name for this fibrous variety of serpentine is chrysolite. Canadian asbestos is the most valuable as a source for textile pur- poses, as it yields a curly fibre easily spun into threads. 6 THE TEXTILE FIBRES. on the market shows that the art of manipulating this substance has reached a high degree of perfection. On account of its incombustible nature, and as it is a very poor conductor of heat, it is made into fabrics where these qualities are especially desired. Thus it is frequently manufactured into gloves and aprons, packing for steam-cylinders, theatrical curtains and scenery, lamp- wicks, etc. The latter use of asbestos was known to the ancients, who employed it for the wicks of the perpetual lamps in their temples. It is from this fact, indeed, that it received its name, the word "asbestos" meaning "unconsumed." It was also employed for napkins on account of its being readily cleansed, it only being necessary to heat the fabric in a flame to make it clean again. In some cases asbestos is spun directly around a copper wire for purposes of insulation. Asbestos, in general, is not dyed, and does not undergo any chemical processes or modes of treatment. When it is desirable to dye it the various substantive dyes may be used with good effect, or the color may be applied by mordant- ing with albumen. The artificial fibres may be divided into two groups: (a) those of mineral origin and (b) those of animal or vegetable origin. In the first division may be classed such fibres as spun glass, metallic threads, and slag wool; in the second division may be put the various artificial silks, such as lustra-cellulose and gelatin silk. Fibres of spun glass are prepared by drawing out molten glass in the form of very fine threads ; * colored glasses may be used to give rise to variously colored threads. Owing to its brittle nature and lack of elasticity, spun glass receives a very limited application, it being made into various ornamental objects, and sometimes into era vats, f A variety of spun glass known as glass wool is used to some extent in the chemical laboratory as a filter- ing medium for liquids which would destroy ordinary filter-paper. * Glass threads can be drawn out so fine that it takes about 1400 miles of the fibre to weigh one pound. t Though fabrics composed of glass are rare, yet colored glass threads are somewhat used for the weft in silk materials for the purpose of producing novel effects, as the glass gives the fabric great lustre and stiffness. CLASSIFICATION OF THE TEXTILE FIBRES. 7 Glass wool is curly, this property being given to it by drawing out the glass thread from two pieces of glass of different degrees of hardness; and by unequal contraction on cooling, this double thread curls up. Various metals are at times drawn out into threads for use in decorative fabrics. Gold, silver, copper, and various alloys are used for this purpose, the metals being heated to redness or until they are in a softened condition. At the present time metallic threads are largely imitated by coating linen yarns with a thin film of gold or silver. Threads of pure gold are seldom made; what is known as u pure-gold " thread is a fine silver wire covered with a thin layer of gold. Silver thread is sometimes made with a core of copper and a layer of silver. Lyon's gold thread consists of copper faced with gold. Metallic threads are usually made into a flattened or band-like form by rolling; by twisting with silk or woolen yarns, the so-called "brilliant" yarns are made. The Cyprian gold thread of old embroideries consists of a linen or silk thread around which is twisted a cover of gilded catgut. Metallic threads are used for quite a large number of fabrics, such as passementerie work, trimmings, brocades, decorative embroidery, church vestments, fancy costumes, tapestries, fancy vestings, etc. Slag wool is prepared by blowing steam through molten slag; it can scarcely be called a textile fibre, but it is used in some degree as a packing material. Artificial silks are made either from cellulose derivatives or gelatin by forcing solutions of these through fine capillary tubes, coagulating the resulting threads, and subsequently subjecting them to various processes of chemical treatment. As these belong more strictly to the class of true textile fibres, they will be given a more extensive consideration, in a further section, as being derivatives of cellulose.* * Artificial cotton is made from pine wood. The latter is cut up into shavings and reduced to the fibre, which is then steamed and boiled under pressure with caustic-soda solution. CHAPTER II. WOOL AND HAIR FIBRES. i. The Sheep. The woolly, hair-like covering of the sheep forms the most important and the most typical of the textile fibres which are obtained from the skin tissues of different animals. The hairy coverings of a large number of animals are employed to a greater or lesser extent as raw materials for the manufacture of different textile products, but those of the various species of sheep make up the great bulk of the fibres which possess any considerable technical importance. Hairs, derived from what- ever species of animals, have very much in common as to their general physical and chemical properties; they are also similar with respect to their physiological origin and growth. The hairs, however, of different animals vary much in the detail of their special characteristics, and also with regard to their adaptability for use in the textile industry; and the wool of the sheep appears to exhibit in the highest degree those specific properties which make the most suitable textile fibre. These properties may be enumerated as being: (a) Sufficient length, strength, and elasticity, together with certain surface cohesion, to enable several fibres to be twisted or spun together so as to form a coherent and continuous thread or yarn; (b) the power of absorbing coloring-matters from solution and becoming dyed thereby, and also the property of becoming decolorized or bleached when treated with suitable chemical agents; (c) in addition to these qualities, which they have in common with almost any textile fibre, wool fibres also possess the quality of becoming felted or matted together, due to the peculiar physical character of their surfaces. This property is a most valuable one, as it 8 WOOL AND HAIR FIBRES. 9 adapts wool to a large number of uses to which other fibres are unsuitable. Silk is also a member of the general group of animal fibres, and though it possesses certain general chemical characteristics in common with wool and hair, yet it has an entirely different physiological origin, being a filament of animal tissue excreted by a certain species of caterpillar, and hence is totally different from wool in its physical properties. There is also a distinct chemical difference in wool and silk. The former contains sul- phur as an essential constituent, while the latter contains no sulphur in its composition. Wool may be specifically designated as a variety of hair growing on certain species of mammalia, such as sheep, goats, etc. The unmodified term "wool" has special reference t6 ~the product obtained from the different varieties of sheep. Cashmere, mohair, and alpaca are the products obtained from the thibet, angora, and llama goats, respectively. Fur is also a modified form of hair, but differs from wool in many of its physical properties,* and is not adapted for use in the manu- facture of spun textiles. It is, however, largely employed for the making of hat felts, f The wool-bearing animals all belong to the order Ruminantia, which includes those animals that chew their cud or ruminate. The principal members of this order are sheep, goats, and camels. The sheep belongs to the class Ovida, and occurs in a number of species which vary considerably in form and geographical distribution, as well as in the character of the wool it produces. Broadly considered, naturalists divide the sheep into three different classes : (a) Ovis aries, commonly known as the domestic sheep, and cultivated more or less in every country in the world. (b) Ovis musmon, occurring native in the European and African countries bordering on the Mediterranean Sea. (c) Ovis ammon, which includes the wild or mountain sheep * The cross-section of wool is almost circular, while that of fui is quite elliptical. f The fur of the hare, rabbit, and cat is occasionally mixed with cotton, wool, or vi ; >un into yarns. Such yarns are principally used for the weav- ing of certain kinds of velvets. 10 THE TEXTILE HBRES. (argali) to be found in Asia and America. The big-horn sheep of the Rocky Mountains belongs to this class.* The domestic sheep is the most important of these classes. It can hardly be said to be indigenous to any one country, for it * A more detailed classification than the above is given by Archer, who divides the sheep into thirty-two varieties: 1. Spanish, or merino sheep (Ovis hispaniam). 2. Common sheep (Ovis rusticus}. 3 Cretan sheep (Ovis strepsiceros). 4. Crimean sheep (Ovis longicaitdatus'). 5. Hooniah, or black-faced sheep of Thibet. 6. Cago, or tame sheep of Cabul (Ovis cagia). 7. Nepal sheep (Ovis selingia). 8. Curumbar, or Mysore sheep. 9. Garar, or Indian sheep. 10. Dukhun, or Deccan sheep. ii Morvant de la chine, or Chinese sheep. 12. Shaymbliar, or Mysore sheep. 13 Broad-tailed sheep (Ovis laticaudatus). 14. Many-horned sheep (Ovis polyceratus), 15. Pucha, or Hindoostan dumba sheep. 1 6. Tartary sheep. 17. Javanese sheep. 18. Barwall sheep (Ovis Barnal). 19. Short-tailed sheep of northern Russia (Ovis brevicaudatus). 20. Smooth -haired sheep (Ovis Ethiopia). 21. African sheep (Ovis Grienensis). 22 Guinea sheep (Ovis ammon Guinensis). 23 Zeylan sheep. 24. Fezzan sheep. 25. Congo sheep (Ovis aries Congensis}. 26. Angola sheep (Ovis aries Angolensis). 27 Yenu, or goitred sheep (Ovis aries steatiniora). 28.. Madagascar sheep. 29. Bearded sheep of west Africa. 30. Morocco sheep (Ovis aries muncedcz). 31. West Indian sheep of Jarraica. 32. Brazilian sheep. These represent the naturally occurring classes of sheep in the different coun- tries; of course, a large number have been emigrated and domesticated in other countries than those in which they had their origin, which has given rise to several sub-varieties. Then, too, new varieties have been formed by cross-breeding and intermixing, which has brought about a considerable variation in the type. The latter is also influenced very largely by climatic conditions, geographical environment, and character of pasturage. WOOL AND HAIR FIBRES. n appears to have been cultivated by the earliest peoples in history, and it has spread over the entire face of the globe with the gradual extension of civilization itself. Different conditions of climate and soil, of pasturage and cultivation, appear to exert a consider- able influence on the variety of the sheep and on the character of the wool it eventually produces. Variations are also produced by cross-breeding and intermixing, and the nature of the fibre has been much altered and improved by careful selection in breeding and genealogical development. Sheep in their natural condition produce two kinds of hair: the one giving a long, stiff fibre, which we will call "beard-hair"; and the other a shorter, softer, and more curly fibre, which we will designate as " wool-hair," or true wool. By domestication and proper cultivation the sheep can be made to produce the latter kind of hair almost exclusively, with but little or none of the hairy fibre. Herein the sheep oiffers essentially from the goat, as the latter will always produce both kinds of fibre, though the fineness and quality of its hair may be much improved by proper cultiva- tion. In addition to the above-mentioned varieties of hair, most . sheep grow more or less of short, stiff hairs, or undergrowth; these have no value as textile fibres. It must be mentioned, how- ever, that the exact character of the wool on the individual sheep varies considerably with its position in the fleece; on the extrenvN ities of the animal the wool becomes more hairy in nature, and j near the feet the short undergrowth of stiff hair is alone to be found. The texture, length, and softness of the fibre also differ considerably in different portions of the fleece.* Hence it becomes necessary, in order to obtain a homogeneous mixture of fibres with properties as constant as possible, to sort out the fibres of the fleece into different portions, which are put together into different grades of wool stock. This operation is termed wool- sorting and grading, and is an important step in the manufacture * In well-cultivated sheep the wool-hairs are usually united in tufts or locks containing a hundred or more fibres. Often several locks are connected into one large one called a staple, the hairs joining the locks together being known as binders. The number of hairs growing on each square inch of the sheep's skin is between 4,500 and 5,500. 12 THE TEXTILE FIBRES. of wool. Different varieties of wool may require different sys- tems and degrees of sorting, but in general the fleece is roughly divided into nine sections, given as follows: (1) The shoulders and sides of the fleece give the finest and most even staples of fibre. (2) The lower part of the back yields a fibre of fairly good staple. (3) The loin and back give a shorter staple, and the fibre is not as strong. (4) The upper part of the legs give a staple of moderate length. The fibre on this part is frequently in the form of loose, open locks and acquires a large amount of burrs by brushing against the spinose fruit of the plant ; the presence of these burrs considerably lessens the commercial value of the wool. South American wool is especially liable to be heavily charged with burrs. (5) The upper part of the neck gives a rather irregular staple which is also very frequently filled with burrs. (6) The centre of the back gives a fine delicate staple similar to that from the loins. (7) The belly, together with the wool from the fore and hind legs, yields a poor staple and a weak fibre. (8) The tail gives a short, coarse, and lustrous fibre, fre- quently containing a considerable amount of kemps. (9) The head, chest, and shins give a short, stiff, and straight fibre, opaque and dead white in color. The merino sheep, which yields what is considered to be the finest quality of wool, appears to have originated in Spain, and at one time was extensively cultivated by the Moors. The exporta- tion of merino sheep from Spain was long guarded against with great care, no one being allowed to take a live merino sheep out of the kingdom of Spain under penalty of death. Later, how- ever, this sheep was brought into various countries, being crossed with the different local breeds with very beneficial results. A German derivative of the Spanish merino known as the Saxony Electoral merino, gives perhaps the highest grade of fibre known in Europe. Australian sheep are mostly derived from merino WOOL AND HAIR. FIBRES. 13 and other high-class stock and yield a wool of the very highest quality. The merino has been cultivated and crossed with other breeds throughout the various parts of the United States, and the latter country is gradually becoming a large producer of middle- grade wool.* The amount of fibre in the fleece varies greatly with the breed, sex, age, and racial conditions of the animal. The average yield from the ewe is 1.75 to 4 Ibs., and from the wether 3.5 to 7.5 Ibs. 2. Physiology and Structure of Wool. Wool, in common with all kinds of hair, is a growth originating in the skin or .cuticle of the vertebrate animals, and is similar in its origin and general composition to the various other skin tissues to be found in ani- mals, such as horn, nails, feathers, etc. Wool is an organized structure growing from a root situated in the dermis or middle layer of the skin, its ultimate physical elements being several series of animal cells of different forms and properties. Herein it differs essentially from silk, which is not composed of cells, but is a continuous and homogeneous tissue. The root of the wool fibre is termed the hair follicle (Fig. 4) ; it is a gland which secretes a lymph-like liquid, from which the hair is gradually developed by the process of growth. The hair follicle also secretes an oil, which is supplied to the fibre during its growth and serves the purpose of lubricating its several parts, giving it pliability and elasticity. In conjunction with the hair follicle there also occur in the skin numerous sebaceous glands which secrete a fatty or waxy substance, commonly known as wool-fat. This substance gradually exudes from the glands and coats the surface of the * According to the National Association of Wool Manufacturers, the wool clip for 1905 in the United States amounted to 295,488,438 pounds; during the same year the net imports of wool were 242,471,489 pounds, giving a total supply of 632,331,459 pounds. The imports of manufactures of wool for 1905 amounted in value to $21,373,- 742, and estimating three pounds of wool in the grease for each dollar in value, we reckon that in the form of manufactured goods there were imported in this year 64,121,226 pounds, which added to the takings of domestic mills (478,667,- 887) amounted to 542,789,113 pounds of wool as approximately representing the consumption of wool by the American people in the way of domestic and foreign manufactures, which, distributed on the basis of the population, amounted to 6.54 pounds of wool per capita required to meet consumptive demand. 14 THE TEXTILE FIBRES. wool in rather considerable amount (Fig. 5). It affords a pro- tective coating to the fibre which serves to preserve the latter from mechanical injury during its growth, and also prevents the sev- eral fibres from becoming matted and felted together. In the preparation of wool for manufacture, this fatty covering has to be removed, the operation constituting the ordinary process of wool- FIG. 4. Section of Hair Follicle. (Xioo.) C, cuticle of skin; R, reta mucosum; PL, papillary layer; S, sebaceous glands; P, papilla; B, bulb of hair; H, hair; F, fibrous tissue; SH, transparent sheath. (Micrograph by author.) scouring. There is also a wool-oil which is contained in the cells of the fibre itself, and is a true constituent of its substance. This oil should not be removed, as its removal causes the fibre to lose much of its elasticity and resiliency. The oil amounts to about i per cent, of the total weight of the fibre, whereas the external fatty matters amount on an average to about 30 per cent. WOOL AND HAIR FIBRES. FIG. 5. Wood Fibre in the Grease. (Xsoo.) A, irregular lumps of grease and dirt; also note that outline of scales is very indistinct. (Micrograph by author.) FIG. 6. Typical Wool Fibres after Removal of Grease. (X350.) (Micrograph by author.) i6 THE TEXTILE FIBRES. Morphologically considered, the wool fibre consists of three distinct portions: (a) A cellular marrow, or medulla, which frequently contains more or less pigment matter to which the wool owes its color; (b) a layer of cellular fibrous substance or cortical tissue which gives the fibre its chief strength and elasticity; ,. i!,' I'', b FIG. 7. Sections of a Hair Fibre. (X5OO.) a, cross-section; b, longitudinal section; A, epidermal layer of scales; B, cortical layer of fibrous cells; C, medullary layer of round cells. (Micrograph by author.) (c) an outer layer, or epidermis, of horn tissue, consisting of flat- tened cells, or scales, the ends of which generally overlap each other, and project outwards, causing the edge of the fibre to present a serrated appearance (Fig. 7). This scaly covering gives the fibre its quality of rigidity and resistance to crushing FIG. 8. Diagram showing Felting Action of Wool. (Drawing by author.) strain ; it also causes the fibres to felt together on rubbing against one another by the interlocking of the projecting edges of the scales (Fig. 8). Any one of these three physical constituents may at times be lacking in a fibre. When the epidermal scales are absent, they have simply been rubbed off by friction; this condition is fre- quently to be found at the ends of long beard- hairs. The cortical layer of fibrous tissue is frequently but slightly developed, espe- WOOL AND HAIR FIBRES. 17 cially in cases where the medulla is large : in some instances, indeed (as in the hair of the doe), the cortical layer appears to be totally absent in the broadest parts of the fibre. The medulla is very frequently absent, or, at least, shows no difference in structure from the cells of the surrounding cortical layer (Fig. 10); this occurs more especially in the wool- hairs, but is also to be found in beard-hairs. On the other hand, the medulla is occasionally more largely developed than the cortical layer, and becomes the FIG. 9. Beard -hair of Doe. (X35O.) Showing small development of cortical layer and large medulla. (Micrograph by author.) principal part of the fibre, as in the beard- hairs of the doe (Fig. 9). The microscopic appearance of wool is sufficiently character- istic to distinguish it from all other fibres. Under even moder- ately low power of magnification the epidermal scales on the sur- face of the fibre can be readily discerned, while neither silk nor the vegetable fibres present this appearance (Fig. n). The scales are more or less translucent in appearance, and permit of the i8 THE TEXTILE FIBRES under cortical layer being seen through them. The exact nature and structure and arrangement of the scales differ considerably with different varieties of wool. _In fine merino wools, for in- stance, the individual scales are in the form of cylindrical cusps, one somewhat overlapping the other; that is to say, a single scale completely surrounds the entire fibre (Fig. 12, M). In some varieties of wool, on the other hand, two or more scales occur in FIG. io. Wool Fibres Deficient in Medullary Cells. A, a fibre without evidence of medullary cells; B, a fibre showing isolated medul- lary cells at M. (Micrograph by author.) the circumference of the fibre (Fig. 12, T). In some cases the edges of the scales are smooth and straight, and this appears to be especially characteristic of fine qualities of wool; the coarser species, on the other hand, possess scales having serrated wavy edges. Usually such scales are much broader than they are long and are very thin. The length of the free or projecting edge of the scale is also a very variable factor; in some wools the scale is free from the body of the fibre for about one-third of the WOOL AND HAIR FIBRES. 19 length of the former, and in consequence the scale protrudes to a considerable extent; -such wool would be eminently suitable for the preparation of material which requires to be much felted (Fig. 12, M). In other wools the free edge of the scale amounts to almost nothing, and the separate members fit down on one another closely, and are arranged like a series of plates. Wools of this class are more hair-like in texture, being stiffer and straighter, w FIG. ii. Comparison of Wool, Cotton, and Silk Fibres. W) wool fibre, showing marking of scales; C, cotton; 5, silk, showing irregular shreds of silk -glue at Sh. (Micrograph by author.) and not capable of being readily felted (Fig. 13). The wool- hairs (the long, stiff fibres which have already been mentioned as occurring to a greater or lesser degree in nearly all wools and also known as beard-hairs) usually possess this structure. The felt- ing quality of wool is much increased by treatment with acid or alkaline solutions, or even boiling water, the effect being to open up the scales to a greater extent, so that they present a much larger free margin and consequently interlock more readily and 20 THE TEXTILE FIBRES. firmly. Woolen yarns, and woven materials made from such yarns, felt much more easily than worsted yarns, due to the fact that the fibres of the former lie in every direction and the inter- locking of the scales takes place more easily. In some varieties of wool fibre the scales have no free edge at all, but the sides fit tightly together with apparently no overlap- ping; in such fibres the surfaces of the scales are also more or FIG 12 Comparison of Different Varieties of Wool. (X5oo.) M, merino wool with only a single scale in circumference of fibre; T, territory wool with two or more scales; C, coarse wool with numerous scales (Micrograph by author.) less concave (Fig. 14). This structure only occurs with thick, coarse varieties of wool. Frequently at the ends of the wool fibre, where the natural point is still preserved (as in the case of lamb's wool from fleeces which have not been previously sheared), the scales are more or less rubbed off and the under cortical layer becomes exposed (Fig. 15, P); this appearance is quite char- acteristic of certain wools. In diseased fibres the epidermal scales WOOL AND HAIR FIBRES. 21 may also be lacking in places, causing such fibres to be very weak at these points (Fig. 15, D). In most varieties of wools the scales of the epidermis may be readily observed even under rather low powers of magnification, while under high powers the individual scales may be seen over- FIG. 13. FIG. 14. FIG. 13. Wool Fibre with Plate-like Scales. (X340.) (Hohnel.) A, portion of fibre with isolated medullary cells at i, and smooth scales e fitting together like plates; B, portion of fibre showing medullary cylinder at m. FIG. 14. Wool Fibre with Concave Scales. (X340.) (Hohnel.) m, medullary cylinder consisting of several rows of cells; e, concave scales arranged in a plate-like manner. lapping one another like shingles on a roof, and showing pointed, thickened protuberances at the edges. When the fibre becomes more hair-like in nature, such as mohair, alpaca, camel-hair, etc., it is more difficult to observe the individual scales, as these fuse together to a greater or lesser degree, until the true hair fibre is reached, which exhibits scarcely any markings of scales at 22 THE TEXTILE FIBRES. all under ordinary conditions. By treatment with ammoniacal copper oxide, however, the interscalar matter is dissolved away, and even with true hair the scaly nature of the surface may be FIG. 15. Wool Fibres showing Absence of Epidermal Scales. (X5oo.) D, at middle portion of fibre, probably due to disease; P, at point of fibre of lamb's wool. (Micrograph by author.) observed. Bowman gives the approximate comparative number of scales per inch in different varieties of wool as follows : Wool. Scales, per inch. Diatn. of Fibre (ins.). East Indian 1000 o . 00143 Chinese 1200 0.00133 Lincoln 1400 o . 00091 Leicester 1450 0.00077 Southdown 1500 0.00080 Merino 2000 o . 00055 Saxony 2200 0.00050 According to the measurements of Hanausek, the size of the epidermal scales on different forms of hair fibres are as follows: WOOL AND HAIR FIBRES. 23 No. of Epidermal Fibre. Scales per mm. Length of Fibre. Sheep's wool, ordinary 97 " ' ' merino 114 " " Electoral 100 ' ' Saxony 121 Angora wool 53 White alpaca . . . . ; 90 Brown alpaca 150 Vicuna wool 100 Camel's wool 90 The epidermal layer of scales imparts to the wool fibre its characteristic quality of lustre. Since the lustre of any surface is due to the unbroken reflection of light from that surface, it may be readily understood that the smoother the surface of the fibre, the more lustrous it will appear When the epidermal scales are irregular and uneven, and have projecting points and rough- ened edges, the surface of the fibre will naturally not be very smooth and uniform, and consequently will reflect light in only a broken and scattered manner. Such fibres will not have a high degree of lustre. On the other hand, when the scales are regular and uniform in their arrangement, and their edges are more or less segmented together to form a continuous surface, the fibre will be smooth and lustrous. As a rule, the coarser and straighter fibres are the more lustrous, as they approximate more closely to the structure of hair, which has a smooth surface. The lustre of the fibre being dependent on the polished surface of the scales is influenced largely by any condition which may affect the latter. Treatment with chemical agents, for instance, which will corrode the horny tissue of the scales will seriously affect the lustre, as is evidenced by allowing alkaline solutions to act on lustrous wool fibres. High temperatures (and especially dry heat) corrodes the epidermal scales and shrivels them up, causing the fibre to lose its lustre. In the various mechanical processes through which the wool must pass in the course of its manufacture, the scales of the fibre suffer more or less injury, being torn apart, roughened, and loosened from the surface. In order to minimize the extent of this injury the wool is generally oiled, so that the surface of the fibres may be properly lubricated. 24 THE TEXTILE FIBRES. The rigidity and pliability of the wool fibre is also largely conditioned by the nature of its epidermal scales. If these fit over one another loosely with considerable length of free edge, the fibre will be very pliable and plastic, soft, and yielding, also easily felted. Whereas, if the scales fit closely against one another and have little or no freedom of movement, the fibres will be stiff and resistant, and not easily twisted together nor felted. The cortical layer, or true fibrous portion of the fibre, forms the major constituent of wool. It consists principally of more or less elongated cells, and often presents a distinctly striated appear- ance, the striations being visible through the translucent layer of scales. The individual cells measure from 0.0014 inch to 0.0025 inch in length, and from 0.00050 inch to 0.00066 inch in diameter, hence are elliptical in form. The cells may be disintegrated from one another by a careful treatment with caustic alkali. To this cortical tissue the fibre chiefly owes its tensile strength and elasticity. When the fibre is fine in staple, the cortical cells exhibit more or less unevenness in their growth and arrangement, with the result that the fibre is contracted on one side or the other, giving rise to the waviness or curled appearance of such wools. It is best, perhaps, to speak of the wool being " wavy" rather than " curled," as the latter implies usually a spiral development which involves a twisting of the fibre, and in wool, as a rule, this does not occur. Coarse wools seldom exhibit this wavy structure, or only to a slight degree, the waves being long and irregular ; some fine stapled wools, on the other hand, possess short and very regular waves. This property of the fibre adds much to its spinning qualities, and also to the resiliency of the yarn or fabric into which it is manufactured. Wool-hairs exhibit much less develop- ment of waves than the true wool fibres, and the more closely the animal fibres approximate to the structure of ordinary hair, the less pronounced are the waves. Sheep's wool is more wavy than that derived from allied species, such as the various goats, camel, etc. Mohair, for instance, exhibits no wavy structure at all. The exact cause which determines the wavy quality of wool is but ill-defined; there appears, however, to be some con- nection between the degree of curl, the diameter of the fibre, WOOL AND HAIR FIBRES. 25 and the number of scales per inch. The following table, given by Bowman, shows the relation between the number of waves and the diameter of the fibre. Wnnl Waves Diameter of per inch. Fibre (ins.). English merino 24-30 o . 00064 Southdown. ~ 13-18 o . 00078 11-16 o.ooioo Irish 7-1 1 o . 00120 Lincoln 3-5 o . 00154 Northumberland 2-4 o . 00172 The waviness of the wool fibre may be temporarily removed by wetting with hot water and drying while in the stretched con- dition. In tensile strength and elasticity, the wool fibre varies within large limits, depending on the breed and quality of the sheep, and also the diameter of the fibre and the part of the fleece from which it was derived. The strength of wool, and of animal hairs in general, is due to the peculiar structure of the fibre. In the first place, the external sheath of horny tissue of flattened cells which take the form of scales, offers considerable resistance to crushing strains, and are also locked rather firmly together in the direction of the length of the fibre; this has a tendency to resist any diminution in the diameter of the fibre which would be felt when the latter is stretched. Then, too, the internal cortical cells of the fibre are so arranged as to present a very firm struc- ture, being firmly interlaced together, consequently they offer considerable resistance to rupture. It has been noticed by a microscopical examination of a broken fibre that the cells them- selves are never ruptured, but only pulled apart from one an- other; this is evidence that the cell- wall is of a strong texture. The latter is probably formed of a continuous tissue which is less than 0.0002 inch in thickness, as under the highest powers of the microscope it exhibits no evidence of structural elements. Bowman gives the following table, which records the average results of a number of experiments on the strength and elas- ticity of the wool fibre : 26 THE TEXTILE FIBRES. Wool. Tensile Strength, grams. Elasticity, per cent. Diameter, ins. Human hair 106 36 6 0.00332 Lincoln wool 23 28 4 ' o 00181 Leicester . -21 27 3 0.00164 28 27.0 0.00149 Southdown wool . ... 5Q 26 8 O OOOQQ Australian merino . 32 7 7 C O OOO5 2 2. S 27 t; O OOO34 IVIohair. ... . 38 20 o o 00170 Alpaca 97 2A 2 o 000^3 It is interesting to compare these figures of tensile strength for equal cross-sections of fibre. As the cross-section varies with the square of the diameter, by taking the ratio of the latter numbers and multiplying by the tensile strength, a figure is obtained which represents the tensile strength for equal diameters of fibres. In this manner the following table has been calculated, taking human hair as the standard for comparison, as it has the largest diameter: Human hair 100 Lincoln wool 96.4 Leicester 1 19 . 9 Northumberland 130 . 9 Southdown wool 62 . 3 Australian merino 122.8 Saxony merino 224.6 Mohair 136 . 2 Alpaca 358.5 Cotton (Egyptian) 201 . 8 It will be noticed from this table that Saxony merino wool is by far the strongest of the different grades of wool. It is also Interesting to note that cotton is considerably stronger than the majority of wools. The medulla, or marrow, of the wool fibre consists of round or slightly flattened cells, usually somewhat larger in section than those comprising the cortical layer (Fig. 7, C). The size of the medulla varies considerably in different varieties and grades of wool, and even shows large variations in fibres from the same fleece. At times it may occupy as much as one-quarter to one- third of the entire diameter of the fibre; and again, it may be WOOL AND HAIR FIBRES. 27 reduced to almost a line, or even disappear completely. Wool- hairs exhibit the presence of a distinct medulla more frequently than the true wool fibres. .The latter mostly show scarcely any inner structure at all, though at times there may be noticed isolated medullary markings, but usually the fibre is so transparent that it presents no markings at all. In camel-hair, however, the medul- lary portion shows up very distinctly, in some fibres appear- ing as a continuous dark band occurring about three-fourths of the width of the fibre, while in other fibres it shows a well-defined granular structure. In hairs of some other animals the medullary part exhibits a structure which is distinctly characteristic of the fibre; in the hair of the cat, for instance, the medullary cells appear in a reticulated form, and in the hair of the rabbit they occur as a series of laminae very regularly superposed on each other. The medullary cells frequently contain pigment matter, either con- tinuously or in isolated cells; and this may occur even in fibres usually classified as white wool. Sometimes the pigment per- meates not only the medulla, but also the cells of the cortical layer, in which case the fibre as a whole appears colored. To this class belong the variously colored wools, ranging from a light brown to almost a black. The hair of camels, goats, and other animals is also more or less colored, and to a much more general extent than sheep's wool. The medulla may consist of a single series of cells, or of several series arranged side by side; sometimes these cells occur in a discontinuous and rather irregu- lar manner, the intervening spaces of the medulla being filled with air. The function of the medulla is to provide the living fibre with an inner canal for the flow of juices whereby it receives nourishment for its growth. It also adds much to the porosity of the fibre, forming a capillary tube whereby the latter may suck up solutions of various kinds, such as dyestufTs, different salts, etc., allowing these to gradually permeate through the cortical layer as well. The epidermal layer of scales is rather impervious to the transpiration of solutions, and only permits of their en- trance into the fibre at the joints of the scales, so it may be seen that the medulla of the fibre becomes an important adjunct in the chemical treatment of wool in the processes of mordanting, 28 THE TEXTILE FIBRES. dyeing, and bleaching. It might also be noted, in this connec- tion, that the epidermal scales become but slightly, if at all, dyed when various coloring-matters are applied to the fibre, but remain clear and translucent. Hence it may be readily under- stood that if two samples of wool are dyed simultaneously, the one consisting of fibres having small and open scales, while the other has a thick and highly resistant epidermis, the resulting color on the two samples will have a different quality or tone, due to the influence on the latter of the uncolored and trans- lucent scales. In wools where this influence is very marked it is almost impossible to obtain rich and full shades of color, due to the transparency and lustre of the surface, which allows of con- siderable white light being refracted through the fibre along with the reflected color. This also explains the well-known fact that the longitudinal surface of the fibre in many cases presents a different tone of color than the cut ends, the latter usually being richer and deeper in tone; as may be noticed in cut-pile fabrics, such as occur in rugs, plushes, etc. In some cases the epidermal layer, instead of being highly translucent, is opaque and white; this is true of many varieties of coarse wool-hairs, and such fibres as cow- hair, etc. In such instances the dyed fibre will lack liveliness of tone and appear rather dead and flat. The further discussion of this interesting subject must be dealt with in more detail in the study of shade matching. Attention is merely called to it at this point in order to emphasize more clearly the funda- mental cause of these differences in color phenomena as lying in the st ucture of the fibre itself. Frequently, through disease or other natural causes, the medulla of the wool fibre is imperfectly developed, in consequence of which the wool will not absorb solutions readily, and hence will not be dyed (or mordanted) at all, or only slightly. These fibres, which are known as kemps, will occur through the mass of the wool as undyed streaks, and will give the yarn or fabric a speckled appearance. Not only may this condition, however, be brought about by natural causes, but it may at times be the result of improper manipulation during manufacturing processes. There is a certain class of wool, for instance, known in trade as WOOL AND HAIR FIBRES. 29 pulled wool; * this is obtained from the pelts of slaughtered sheep, and is usually removed from the skin by the action of lime, the fibres being pulled out by the roots. In the process, the medulla becomes stopped up with solid insoluble particles of lime, which is also true of the end pores of the cortical layer and the joints of the scales. As a consequence, the fibre is very difficult to impreg- nate with solutions, and will remain more or less completely undyed. This non-porous character is also enhanced, perhaps, by the fact that the fibre does not possess a freshly cut end, but still retains the root, which is more or less rounded off and closed by the coagulation and hardening of the juices in the hair follicle. The medulla, as a rule, is more developed in beard-hairs than in wool- hairs, and more in coarse grades of wool than in the finer qualities. There also appears to be more or less relation between the breed of the wool and the morphological charac- teristics of the medullary cells, although this is a subject which as yet has been but little studied. At times the medullary cells exhibit but little differentiation from those of the cortical layer, and these two portions of the fibre become continuous in their appearance, that is to say, no line of demarcation can be drawn between the medulla and the surrounding cortical layer. In length, the wool fibre varies between large limits, not only in different sheep, but also in the same fleece. Generally speaking, the length may be taken as being between i and 8 inches. The diameter of the fibre is also very variable, even in the same fleece, but may be taken as averaging from 0.0018 to 0.004 inch.f According to their length of staple, wool fibres are graded into two classes: tops and noils. The former includes the longer stapled fibres, which are combed and spun into worsted yarns, to be manufactured into trouserings, dress-goods, and such fabrics as are not fulled to any extent in the finishing. The latter class consists of the short-stapled fibres, which are carded and spun into woolen yarns to be used for weft and all classes of goods which * This is also known as tanners 1 wool and glovers' wool. f According to Hohnel, the diameter of sheep's wool varies from 10 to 100 /* (the expression /*=-nnnr mm -)5 an( l according to Cramer, the thickness of the hairs from one and the same fleece may vary from 12 to 85 fi. 30 THE TEXTILE FIBRES. v are fulled more or less in the finishing operations, where a felting together of the fibres is desired. On comparing worsted and woolen yarns, it will be noticed that the former are fairly even in diameter and the individual fibres lie more or less parallel to each other, whereas in woolen yarns the diameter is very uneven, and the fibres lie in all manner of directions. The quality of wool obtained from sheep depends very largely on the breed, on climatic conditions, and nature of the pasturage on which the sheep feed. Australia appears to possess the cli- matic conditions best adapted for wool-growing.* With regard to the nature of the pasturage it has been found that grass from chalky soils gives rise to a coarse wool, whereas that from rich, loamy soils produces fine grades of wool.f As a rule, the sheep * Other conditions being equal, long droughty seasons in wool-growing dis- tricts will cause the fibre to be much shorter than otherwise, t Utah wools, for instance, are harsh and stairy compared to Wyoming wools. This is due to the alkali in the soil in Utah and the dryness of the climate. The alkali in the soil and the effect it has upon the water which the sheep drink have a tendency to take the life out of the wool and weaken the staple. The more close and uniform the fibres lie, the better will be the combing qualities of the wool. The Utah wools in this respect are inferior to the Wyomings, Idahos, and Montanas, especially the wools grown in southern Utah. In northern Utah the wools are longer than in southern Utah, but there are very few Utahs either north or south which are fit for combing. The heaviest shrinkage wools gen- erally come from eastern Oregon and Nevada. The degree of shrinkage depends to a considerable extent on the season in which the wools were grown. A wet season and long-continued rains will wash much dirt and dust out of the wools, thus leaving them lighter. The lightest shrinkage wools come from Virginia and Kentucky and the Blue Grass region, where medium wools are grown, where the sheep are cleaner, the range better, and the country hilly, and where com- paratively little sand and dirt work their way into the fleece. The shrinkage of washed fleeces ranges from 55 to 35 per cent. Unwashed Indiana wools shrink 38 to 43 per cent. Missouris will shrink around 43 to 45 per cent.; Illinois, 45 to 47 per cent. California wools shrink 55 to 72 per cent., depending on the part from which they come. The heaviest shrinkage wools are in southern Cali- fornia, because of the presence of more sand and dirt, and inferiority of the range. Texas spring wools shrink anywhere from 64 to 72 per cent., and the fall wools 58 to 64 per cent. Territory wools shrink from 55 up to 73 per cent. Idahos on the medium order will not shrink over 55 per cent. Wyoming wools on the fine and fine medium order shrink 65 to 72 per cent. The Montanas shrink on the average 63 to 69 per cent, for fine and fine mediums, and 57 to 60 per cent, for mediums. The shrinkage on Arizona wools will range from 66 to 73 per cent., but they will spin to finer counts than the Utah wools, and will scour WOOL AND HAIR FIBRES. v 31 which yield the best qualities of wool give the poorest quality of mutton. Unhealthy conditions of. the sheep almost always influence the fibre during that period of its growth. If the sheep, for example, is suffering from indigestion, cold, lack of proper nour- ishment, etc., the fleece during that time will develop tender fibres; when the sheep regains its normal condition of health, the fibre becomes strong again. Thus the fleece may have tender strata through it which will considerably affect the fibre and its uses. These tender spots, of course, render the wool unfit for combing purposes, and it must go into the "clothing" class, and will consequently sell for less money, other things being equal. It is no great injury to the wool, however, aside from spoiling it for combing, as the wool, after it has passed the tender spot, grows fully as well as before the sheep was ill. When sheep have been afflicted with scab, the latter shows itself in tender wool at the bottom of the fibre. The scab leaves a pus-like substance which adheres to the bottom of the fibres and dries there. Vermin on sheep have an influence on the wool; these creatures leave dis- colorations on the fibre which cannot be removed by scouring. The wool, being "off color,' 7 does not sell as well, and, moreover, the fibre is liable to be tender. As to the amount of wool to be obtained from each sheep, it may be said that the average yield is from 4 to 15 Ibs., though in some South American varieties the fleece may weigh as high as 30 to 40 Ibs. With respect to the variation in fibres derived from different kinds of sheep, Bowman gives the following classifica- tion: out very white. In this latter respect the Wyoming wools are superior to any other grown west of the Mississippi River. The shortest wools grown in America are from California and Texas; they are used principally for felts and hats, though they can also be mixed in certain proportions with clothing wool. As the Territory wools are grown mostly in dry climates, they will gain somewhat in weight on being shipped to the Atlantic seaboard and stored for a few months. Utah wools will gain about i per cent., Montana wools about per cent., and Wyoming wools about i per cent. The wools from Ohio and other eastern States will not gain anything; in fact, will sometimes show a slight shrinkage. (Ameri- can Wool and Cotton Reporter.) 32 THE TEXTILE FIBRES. (1) Those sheep the fibres of whose wool most nearly approach to a true hair, the epidermal scales being most horny and attached most firmly to the cortical structure. This class includes all the lustrous varieties of wool, besides alpaca and mohair. (2) Those where the epidermal scales, though more numerous than in the first class, are less horny in structure and less adherent to the cortical substance of the fibre. This class includes most of the middle- wooled sheep and half-breeds. (3) Those where the characteristics of true wool are most highly developed, such as suppleness of fibre and fineness of texture, the epidermal scales being attached to the cortical sub- stance through the smallest part of their length. This class includes all the finest grades of sheep, such as the merino and crosses with it. CHAPTER III. THE CHEMICAL NATURE AND PROPERTIES OF WOOL AND HAIR FIBRES. i. Chemical Constitution. In its chemical constitution wool is closely allied to hair, horn, feathers, and other epidermal tissues. A distinction must be made between the fibre proper and the raw fibre as it comes from the fleece. In the latter condition it contains a large amount of dirt, grease, and dried-up sweat which have first to be removed by the scouring process before the pure fibre is obtained. Reserving these impurities for a further discussion which does not concern us at this point, and discussing only the fibre itself, it has been found to consist of five chemical elements; namely, carbon, hydrogen, oxygen, nitrogen, and sulphur. Nitrogen is an ingredient common to both wool and silk, but sulphur is distinctly characteristic of wool and hair fibres. To show the average amount of pure fibre to be obtained from raw fleece wool, the following analysis by Chevreul of a merino wool is given : Per Cent. Earthy matter deposited by washing the wool in water 26.06 Suint or yolk soluble in cold distilled water 32 . 74 Neutral fats soluble in ether 8.57 Earthy matters adhering to the fat i . 40 Wool fibre 31 . 23 100.00 These figures are based on wool dried at 1 00 C. ; if corrected for air-dry wool containing 14 per cent, of moisture, this would give only about 27.5 per cent, of pure fibre. Of course, the 33 34 THE TEXTILE FIBRES. amount of fibre will vary considerably in different qualities and samples of wools, but this figure may be taken as a fair average. The presence of nitrogen in wool is readily made evident by simply burning a small sample of the fibre, when the character- istic empyreumatic odor of nitrogenous animal matter will be observed. By heating wool in a small combustion test-tube it will be noticed that ammonia is among the gaseous products evolved, and can be tested for in the usual manner. The pres- ence of sulphur in wool can be shown by dissolving a sample of the fibre in a solution of sodium plumbite (obtained by dissolving lead oxide in sodium hydrate), when a brown coloration will be observed, due to the formation of lead sulphide. On adding hydrochloric acid to the solution and heating, the odor of sul- phuretted hydrogen will be distinctly noticed. The application of this test to show the presence of sulphur in wool is sufficient to discriminate chemically between that fibre and those consisting of silk or cotton, and also to detect wool in admixture with other fibres. The older methods of hair-dyeing were based on this same reaction, solutions of soluble lead salts, such- as sugar of lead, being applied to the hair, with the result that lead sulphide would be formed and cause a dark brown coloration. The use of such preparations, however, is dangerous, as they are liable to cause lead -poisoning. The presence of sulphur in wool may at times be the cause of certain defects in the dyeing process. In neutral or alkaline baths, if lead is present, the color obtained on the fibre will be more or less affected by the lead sulphide formed on the wool, and serious stains may be the result. The presence of sulphuric acid, however, prevents this, and no staining of the fibre takes place. Stains are sometimes produced when wool is mordanted with stannous chloride, as in the dyeing of cochineal scarlets, due to the formation of stannous sulphide. Occasionally woolen printed goods exhibit brownish stains on the white or light- colored portions after being steamed. These may be due to slight traces of copper or lead being deposited on the cloth during its manipulation and passage through the machines, and these metals when the wool is steamed form dark colored sulphides which cause WOOL AND HAIR FIBRES. 35 the stains. By locally applying a weak solution of hydrogen peroxide such discolorations may be removed without injury to the printed color. Chevreul recognized the fact that in certain dyeing operations it was necessary to remove the sulphur from wool as far as possible in order to obtain the best results. He accomplished this by steeping the wool in milk of lime and afterwards in a weak bath of hydrochloric acid, and finally washing. The amount of sulphur existing in wool does not appear to be a very constant factor, but varies in different samples of wool from 0.8 to 4 per cent.* The manner in which the sulphur exists in the molecular structure of the fibre is by no means clear, a s the majority of it is readily removed without any apparent struc- tural modification of the fibre itself. According to Chevreul the amount of sulphur in wool was reduced to 0.46 per cent, by several treatments with lime-water. Treatment with a concen- trated solution of caustic soda in such a manner as not to disinte- grate the f-bre (see p. 46) will remove as much as 84.5 per cent, of the sulphur originally present in the wool. On a sample of wool containing 3.42 per cent, of sulphur, treatment in this man- ner left only 0.53 per cent, of sulphur in the fibre. This would appear to indicate that the sulphur is not a structural constituent of the wool fibre, f The fact, however, that the sulphur present is not all removed by even such severe treatment as described would also serve to indicate that this element may exist in wx>ol in two forms, the one an ultimate constituent of the fibre, and the other, and major part, as a more loosely combined compound. The fact that the amount of sulphur naturally present in wool is * Wool is similar to other albuminoids in that it contains a relatively small though a widely fluctuating amount of sulphur. The following sulphur com- pounds have been isolated from the decomposition products of the albuminoids: Cystin, cystein, thiolactic acid, thioglycollic acid, ethyl sulphide, ethyl mercap- tan, sulphuretted hydrogen, and diethyl-thetin. fThe presence of sulphuric or sulphurous acids has formerly never been observed in the decomposition products of albuminoids and this led to the opinion that the albumin molecule did not contain sulphur in combination with oxygen. Raikow (Chem. Zeit., 1905, page 900), however, finds that when purified, un- bleached wool is treated with phosphoric acid considerable quantities of sul- phurous acid are evolved. 36 THE TEXTILE FIBRES. by 'no means constant would also tend to support this view; as would also the fact that the major portion of the sulphur is so readily spilt off to form metallic sulphides. On dissolving wool in boiling caustic soda, it does not appear that all of the sulphur is converted into sodium sulphide, as only about 80 per cent, of it can be obtained as hydrogen sulphide when the caustic soda solution is treated with acid. Probably the remainder of the sulphur exists in the wool as a sulphonic acid, or some compound of a similar nature. In its chemical nature wool appears to be a proteoid, known as keratin. As its constituents are not rigidly constant in their proportions, we cannot assign to wool a definite chemical for- mula.* On an average, its composition may be taken as follows ; Carbon ........... 50 Hydrogen . . . , 7 Oxygen 26-22 Nitrogen I5- X 7 Sulphur 2- 4 * Keratin, free from ash, water, and melanin, on hydrolysis gave the follow- ing amounts of monamino -acids: Keratin from Keratin from Horse-hair, Goose-feathers, Per Cent. Per Cent. Glycin , 4-7 2.6 Alanin 1.5 1.8 Amino-valeric acid > 0.9 0.5 Leucin 7.1 8.0 Pyrolidin-2-carboxylic acid 3.4 3.5 Aspartic acid 0.3 i.i Glutamic acid 3.7 2.3 Tyrosin 3.2 3.6 Serin 0.6 0.4 (Abderhalden, Zeit. physiol. Chem., vol, 46, p. 31.) According to the tables of Cohnheim, the percentages of known constituents in the keratin from hair are as follows: Per Cent. Leucin 14 Glutaminic acid 12 Aspartic acid not determined Cystin 13.92 Tyrosin 3 Ammonia large amount WOOL AND HAIR FIBRES. 37 Bowman gives the following analyses of four different grades of English wool: Constituent. Lincoln Wool. Irish Wool. Northum- berland Wool. South- down Wool. 5J-3 6.0 17.8 20.2 3-8 Carbon 52.0 6.9 18.1 20.3 2 -5 0.2 49.8 7.2 I 9 .I 19.9 3-o i .0 50.8 7-2 I8. 5 21 .2 2-3 Hydrogen Sulphur, Loss These analyses were made of wool which had been purified by extraction with water, alcohol, and ether. The continued action of boiling water appears to decompose the wool fibre to a certain extent, as both ammonia and hydrogen sulphide may be detected in the gases evolved.* By heating wool to a temperature of 130 C. with water under pressure, the fibre appears to become completely disorganized, and on drying may be rubbed into a fine powder. At higher temperature the fibre is completely dissolved. Based on this feet, Knecht has proposed a method for the carbonization of wool in mixed woolen and silk goods, for the purpose of recovering the silk, as the latter is noi materially affected by this treatment.! The wool fibre as a whole does not appear to be a homogeneous chemical compound; instead of being a simple molecular body to which a definite formula might be given, it is doubtless com- posed of several chemically distinct substances. This is evi- denced by the fact that the proximate constituents of wool are by no means constant in their amount ; furthermore, certain of its constituents are in part removed by simply boiling the fibre in water without a structural disorganization taking place. The sulphur content is especially liable to fluctuation, and is the most * The soluble decomposition products of wool produced by boiling with water show all the characteristic properties of the peptones. Suida suggests that this action of boiling water on wool may account for the lack of fastness to rubbing often noticed with basic colors on wool. t This method, though theoretically possible, does not have any practical value. 38 THE TEXTILE FIBRES. readily removed cf the chemical elements of which the fibre is composed; in fact, so easily is some of the sulphur removed as such by various solvents, that it would seem to indicate that this con- stituent existed in wool either in the free condition or in a com- pound of exceedingly unstable character. Schuetzenberger, by decomposing pure wool fibre by heating with a solution of barium hydrate at 170 C., obtained the fol- lowing decomposition products: Per Cent. Nitrogen (evolved as ammonia) 5 . 25 Carbonic acid (separated as barium carbonate) 4- 2 7 Oxalic acid (separated as barium oxalate) 5.72 Acetic acid (by distillation and titration) 3- 2 Pyrrol and volatile products i to 1.50 f C 47-85 Proximate composition of fixed residue, containing leu- j H 7 . 69 cin, tyrosin, and other volatile products j N 1 2 . 63 ' O 31-83 Williams has shown that by distilling wool with strong caustic potash a large amount of ammonia was obtained in the distillate, together with butylamin and amylamin. Dry distillation of wool yields an oil of a very disagreeable odor, probably consist- ing cf various sulphuretted bases; also a considerable amount of pyrrol and hydrogen sulphide gas, together with a small amount of carbon disulphide, and traces of various oily bases. The fatty and mineral matters present on the raw wool fibre consist on the one hand of wool grease derived from the fatty glands surrounding the hair-follicle in the skin, and on the other hand of dried-up perspiration from the sudorific glands in the skin. The wool grease is mostly to be found as the external coating on the fibre * which serves to protect it from mechanical injury and felting while in the growing fleece. f There is also a * The statement made in some text-books that raw wool when left in the greasy condition is not attacked by moths is erroneous. The personal experi- ence of the author has proved that raw wool is as liable to the depredations of insects as washed and scoured wool. f Cotted fleeces are those in which the fibres have grown in and amongst each other on the sheep's body, so that they form a more or less perfect mat of wool. These mats are hard or soft according to the extent to which the matting process has been carried on. Cotted fleeces occur mostly in sheep which have been housed; they are seldom found in the territories where the sheep run on the range WOOL AND HAIR FIBRES. 39 small amount of oily matter contained in the medullary intercellu- lar structure of the fibre which appears to have the function of acting as a lubricant for the inner portion of the fibre, thus pre- serving its pliability and elasticity. Wool grease does not appear to be a simple compound, but evidently consists of several oils and wax-like compounds. Its chief constituent is cholesterol, which appears to be one of the higher monatomic alcohols, and is not a glyceride. Analysis shows it to have the formula C 2 6H 43 OH. It is a solid wax-like substance which very readily emulsifies in water. Associated with cholesterol there is also an isomeric body called isocholesterol. Besides these solid waxes, wool grease also contains two fats which have been studied by Chevreul to some extent. These are described as follows: (a) Stearerin, a neutral solid fat, melting at 60 C. ; contains neither nitrogen nor sulphur; does not emulsify with boiling water, but emulsifies without saponification when boiled with caustic potash and water; it is soluble in 1000 parts of alcohol at 15.5 C. (b) Elairerin, a neutral fat melting at 15.5 C.; also free from nitrogen and sulphur; it emulsifies with boiling water, and is saponified with caustic potash; it is soluble in 143 parts of alcohol at i5-5 C. The dried-up perspiration adhering to the raw-wool fibre is also called suint. It consists principally of the potash salts of various fatty acids, and it is soluble in water, wherein it differs from wool grease. On extraction with water, suint will yield a dry residue of about 140 to 180 Ibs. for 1000 Ibs. of raw wool. This on ignition will give 70 to 90 Ibs. of potassium carbonate and 5 to 6 Ibs. of potassium sulphate and chloride, so that the and are more exposed and hardy. Cotted fleeces indicate a low degree of vitality, and many are to be found in fleece wool from States east of the Mississippi River, They may be caused by sickness or a low state of the blood, or they may be found in an old sheep which is giving out or is run down, which contributes to the frowsy condition of the wool. Cotted fleeces are unfit for combing purposes, as they have to be torn apart, and frequently they are so dense and hard that the fibres can only be pulled apart by the use of special machinery. Badly cotted fleeces are used frequently for braid purposes. 40 THE TEXTILE FIBRES. amount of potash salts to be derived from raw unwashed wool may be taken to be about 10 per cent, on the weight of the wool. Besides the mineral matter existing in the soluble suint, there is also a small amount of mineral matter which appears to form an essential constituent of the fibre itself.* It is left as an ash when wool is ignited, and amounts on an average to about i per cent., the majority of which is soluble in water and consists of the alka- line sulphates. The following analysis by Bowman shows the typical composition of the ash of Lincoln wool: Per Cent. Potassium oxide 31.1 Sodium oxide 8.2 Calcium oxide 16.9 Aluminium oxide 1 Ferric oxide / ' Silica 5.8 Sulphuric anhydride 20.5 Carbonic acid 4.2 Phosphoric acid trace Chlorin trace Sheep's wool is nearly always white in color, though sometimes- it may occur in the natural colors of gray, brown, or black. The coloring-matter in wool appears to withstand the action of alkalies * Arsenic appears to be present in nearly all samples of wool, even in the natural state. The arsenic is generally derived from the dips to which the sheep are subjected even the wool from a lamb whose mother has been dipped a con- siderable time before the lamb's birth will show distinct traces of arsenic. Thorpe gives the following figures for the amounts of arsenic in woolen materials: Arsenious Oxide, Mgms. per Gram of Material. Flannel from natural wool o . 005-0 . 009 White Berlin wool o . 037 Cream flannel o . 004 Welsh flannel o . 015 Vest wool (undyed). . . o . on Linen (white) free Silk (undyed) o.ooi Wool, from lamb (mother treated with arsenical dip). . 0.0005 Wool from lamb (mother dipped shortly before birth of the lamb) o . 019 . Wool from ewe (treated with carbolic dip 15 months previously) 0.047 WOOL AND HAIR FIBRES. 41 and acids, though it is not especially permanent toward light. It appears to be distributed in the fibre in quite a different manner from that of the artificially applied dyes. The natural coloring- matter appears to be contained particularly in the cells of the cortical layer and the marrow in a granular form, and to occur to a greater extent in the medullary than in the cortical cells. In fibres which are only slightly colored the walls of the cells are almost colorless; though when the fibre becomes very strongly colored the cell-walls also appear to be impregnated with the coloring-matter. In wools which have been dyed, however, the cell- walls are nearly always uniformly colored, in consequence of which the medulla of the fibre becomes less pronounced; whereas, with naturally colored wools, the medulla is usually rendered more distinct through the deposit of coloring-matter. 2. Chemical Reactions. In its chemical reactions wool ap- pears to exhibit the characteristics both of an acid * and a base, and no doubt it contains an amido acid in its composition. The presence of an amido group is evidenced by the formation of ammonia as one of the decomposition products of wool, also by the strong affinity of wool for the acid dyestuffs, or even of its ability to combine with acids in general. Schuetzenberger has shown that the products of the hydrolysis of wool by baryta- water are analogous to those of albuminoids containing imido groups; the experiments of Prud'homme and Flick also indicate the presence of imido rather than amido groups in wool. The fact that wool absorbs nitrous acid, and combines with phenols, which is supposed to indicate the pres- ence of amido groups, may be explained by the formation of nitrosamines with the imido groups, which would also yield col- ored derivatives with phenols. * The acid nature of wool accounts for the possibility of the formation of compounds of the fibre with various metallic salts, alkalies, and metallic oxides, and therefore for the difference in behavior in dyeing between wools which have been scoured with alkaline carbonates or treated with metallic salts or hard water and wool which has not had its acid groups saturated in this way. It also accounts for the fact that different wools require the addition of different amounts of acid to the dye-bath to give the same effect. (See experiments of Gelmo and Suida, Ber. Akad. Wissenschaften, May, 1905.) 42 THE TEXTILE FIBRES. The coefficient of acidity, which is a figure meaning the num- ber of milligrams of caustic potash neutralized by one gram of substance, has been determined for wool, together with a number of other albuminoids, as follows: Wool 57- Albumin 20.9 Silk 143-0 Gelatin 28.4 Globulin 101 . 5 Although the amount of acid absorbed and neutralized by wool may be thus quantitatively determined, the amount of alkali absorbed cannot be so obtained, as wool, though it absorbs alka- lies, does not neutralize them.* By treatment with concentrated solutions of caustic soda (80 Tw.) wool absorbs about 50 per cent, of its weight of sodium hydrate from solution. Nor can this alkali be totally removed from the wool by subsequent washing with water alone, but requires a treatment with acid for complete neutralization. Wool so treated exhibits a lessened affinity for basic dyes, showing a probable neutralization to a greater or lesser extent of its acid component. The amido acid of keratin has received the name of lanu- ginic acid, and has been prepared by dissolving purified wool in a strong solution of barium hydrate, precipitating the barium by means of carbon dioxide, and after filtering, treating the liquid with lead acetate, whereby the lead salt is obtained. This is decomposed by means of hydrogen sulphide, and the lanuginic acid obtained, after evaporation, as a dirty-yellow substance Its solution in water yields colored lakes with the acid and basic dyestuffs, and also with the various mordants. According to Knecht, lanuginic acid possesses the following properties: It is soluble in water, sparingly so in alcohol, and insoluble in ether. Its aqueous solution yields highly colored precipitates with the acid and basic dyestuffs; tannic acid and * Wool which has been treated with a dilute solution of caustic alkali appar- ently shows no difference from untreated wool in its dyeing properties with re- spect to acid and basic dyes. That alkali has been absorbed by the wool, how- ever, is shown by the fact that it has an increased attraction for such dyes as Benzopurpurin and Bordeaux, which only dye wool from a slightly alkaline bath. WOOL AND HAIR FIBRES. 43 bichromate of potash also give precipitates. The following mordants in the presence of sodium acetate also give precipitates: alum, stannous chloride, copper sulphate, ferric chloride, ferrous sulphate, chrome alum, silver nitrate, and platinum chloride. Lanuginic acid exhibits all the properties of a proteoid, and may therefore be classed among the albuminoids; it is soluble in water at all temperatures, and its solution is not coagulated. With Millon's reagent and with the double compound of phos- phoric and tungstic acids, it shows the characteristic albuminoid reactions. Knecht recommends the use of a solution of wool in barium hydrate for the purpose of animalizing vegetable fibres. Cotton so treated is capable of being dyed with acid and basic dyestufls. When heated to 100 C., lanuginic acid becomes soft and plastic, and the majority of its colored lakes also melt at this temperature. Knecht gives the following analysis of lanuginic acid: Per Cent Carbon 41.61 Hydrogen 7.31 Nitrogen 10.26 Sulphur. 3 . 35 Oxygen 31 . 44 93-97 Though lanuginic acid contains a notable amount of sulphur in its composition, it is not blackened by treatment with sodium plumbite. When treated with dilute acids, the wool fibre does not appear to undergo any appreciable change; although, from the fact that acids are very readily absorbed by wool and very tenaciously held by it, there is reason to believe that some chemical combination takes place between the fibre and the acid. It can be shown, for example, that if wool be treated with dilute sulphuric acid,* all of * Wool that has been treated with warm dilute solutions of sulphuric acid not only shows an increased affinity for acid colors, but also a much decreased affinity for basic colors. Treatment of wool with cold aqueous or alcoholic solu- tions of sulphuric acid, however, followed by washing with cold water, appears to diminish the affinity of the fibre for acid colors, from which it is concluded 44 THE TEXTILE FIBRES. the acid cannot again be extracted by boiling in water until the wash-waters are perfectly neutral; and wool thus prepared has the power of combining with the various acid colors without the necessity of adding any acid to the dye-bath. It is also true that if wool which has been treated with sulphuric acid is boiled in water, ammonium sulphate is to be found in the solution, showing that some chemical action has probably taken place between the acid and some basic constituent of the wool fibre. Hydrochloric acid acts much in the same manner as sulphuric acid, although the amount permanently absorbed by the fibre is quite small, most of the acid being removed by boiling water. Chromic acid is also absorbed in like manner, and no doubt the usefulness of bichromates as mordants for wool depends somewhat on the chemical combination between the fibre and the chromic acid. With nitric acid wool behaves somewhat differently, for unless the acid be very dilute and the temperature low, the fibre will assume a yellow color, which is probably due to the formation of xanthoproteic acid. Formerly this yellow color was supposed to be due to the formation of picric acid, but this view is erroneous. Nitric acid has a similar effect on the skin, the yellow stains which it produces being a subject of common experience. If the strength of the acid is below 4 Tw., the yellow coloration on wool is not very marked, and in this manner nitric acid has been largely employed as a stripping agent, especially for shoddies. Richards has shown that by the action of nitrous acid, wool is diazotized in a manner similar to an amido compound, and may be developed subsequently in an alkaline solution of a phenol, giving rise to quite a variety of shades. When wool is treated in the dark with an acid solution of sodium nitrite (6 per cent.) it quickly acquires a pale-yellow color, rapidly changing on expo- sure to light. Wool prepared in this manner is turned brown by that the acid is fixed in a somewhat different way than when the wool is heated with the acid solution. Acidified wool also shows an increased power of dyeing alizarin colors direct. Other acids have about the same effect on wool as sul- phuric acid, only in the case of acetic acid it is necessary to add the acid directly to the dye-bath in order to hinder the fixation of basic colors or increase the ab- sorption of acid colors. (See Gelmo and Suida, Ber. Akad. Wissenschajten, May, 1905.) WOOL AND H/IIR FIBRES. 45 boiling water, and caustic soda effects the same change, the color becoming yellow again on treatment with acids. Stannous chlo- ride in a warm solution discharges the brown color. Diazotized wool appears to have an increased attraction for basic dyes and a lessened affinity for the acid dyes. Exposure to light bleaches diazotized wool, which is then turned orange by alkalies, and not brown. The following colors may be obtained by treating diazotized wool with various phenols in alkaline solution: Phenol. Color. Reaction with HjjSO* Resorcin Orange Pale red Orcin Orange Pale red Pyrogallol Yellowish brown Orange Phloroglucin Bordeaux No change a-Naphthol Red Black /?-Naphthol Red Pale red When dyed in connection with metallic mordants, these phenol colors are fast to light, fulling, acids, and boiling water. Tin mordants give yellow and orange shades, aluminium orange, iron dark browns and olive browns, chromium and copper garnet. Wool treated with nitrous acid acquires a harsh feel and is non- hygroscopic. Its acid number is 169, and its iodin number 4.7, whereas untreated wool has the numbers 88 and 18.4 respectively. It also appears to contain less nitrogen than ordinary wool (Lidow, Cktm. Centr., 1901, i, 703). Vignon (Compt. Rend., 1890, No. 17) has experimented on the amount of heat disengaged by treating wool with different acids and alkalies, with the following results, using 100 grams of unbleached wool: Reagent. Calories Liberated. Potassium hydrate (normal) 24 . 50 Sodium hydrate (normal) 24 . 30 Hydrochloric acid (normal) 20 . 05 Sulphuric acid (normal) 20.90 These figures are interesting in indicating the relative acidity and alkalinity of the wool fibre. In common with most other organic substances, wool is 46 THE TEXTILE FIBRES. totally destroyed by the action of concentrated mineral acids.* With organic acids, wool is usually reactive, readily absorbing oxalic, lactic, tartaric, acetic, etc., acids. Tannic acid, however, is an exception, and is not absorbed to any extent by the fibre. But if wool is treated in a boiling solution of tannic acid and the latter fixed in the fibre by a subsequent treatment in a solution of tartaric emetic (or other suitable metallic salt), it will be found that the fibre becomes altered in such manner that it no longer exhibits its normal affinity towards acid, substantive, and mor- dant dyes. Towards basic dyes, however, the affinity of the wool becomes considerably increased by reason of the presence of tannin. Although so resistant to the action of acids, on the other hand, wool is quite sensitive to alkalies; so much so, in fact, that a five per cent: solution of caustic soda at a boiling temperature will completely dissolve wool in five minutes. From this fact it is easy to understand why soaps, and scouring and fulling agents in general, should be free from appreciable amounts of caustic alkalies. The weaker alkaline salts, such as the carbonates, soaps, etc., are not so destructive in their action, and when em- ployed at moderate temperatures they are not regarded as dele- terious, and are largely used in scouring and fulling. With respect to the amount of caustic alkali necessary to decompose wool, Knecht found that on boiling wool for three hours with three per cent, (on the weight of the wool) of caustic soda the fibre was not disintegrated, but on increasing the amount to six per cent., complete disintegration took place and the wool was almost entirely dissolved. The action of concentrated solutions of caustic alkalies on wool is a rather peculiar one.f Solutions of caustic soda of a strength below 75 Tw. will rapidly disintegrate the fibre, but with solutions of 75-! 00 Tw. the fibre is no longer disintegrated, * On treatment with cold concentrated sulphuric acid for a short time wool is not seriously disintegrated; the fibre, however, suffers a change in that it loses all affinity for acid dyes, while it strongly attracts basic dyes. (Text, Rec., vol. 22, p. 229.) f Kertesz, Farber-Zeit., vol. 9, pp. 35-36; Buntrock, ibid., vol. 9, pp. 69-71. WOOL AND HAIR FIBRES. 47 but, on the other hand, increases from 25 to 35 per cent, in tensile strength, becomes quite white in appearance, and acquires a high lustre and a silky scroop. The maximum effect is obtained by using a caustic soda solution of 80 Tw. and keeping the tem- perature below 20 C.* The duration of the treatment should not be more than five minutes. The addition of glycerol to the solution of caustic soda renders the action of the alkali more effective. Wool treated in this manner may be said to be "mer- cerized," though the action of the caustic soda in this case is not quite analogous to that in the mercerization of cotton. From the decrease in the density of the caustic soda solutions employed, it has been shown that the wool absorbs a considerable amount of sodium hydrate from solution. Whether this is held by the wool in true chemical combination has net been ascertained. The treated wool contains but a small amount of sulphur com- pared with that present in the original fibre (see page 35); analy- sis, in fact, shows that only about 15 per cent, of the original sul- phur remains in the mercerized wool. The dyeing qualities of the latter are also different from the original fibre in that it absorbs more dyestuff from solution and hence yields heavier shades. Quantitative tests have shown that the increase in the absorption of dyestuff s is as follows: Class of Dyestuffs. *% Basic 12.5 Acid 20.0 Substantive 25.0 Mordant 33.3 Mercerized wool also shows an increased absorption with respect to solutions of various metallic salts. The exact nature of the action of caustic soda under the con- ditions given is rather difficult to satisfactorily explain. Through a microscopic examination of the treated fibres it appears that the individual scales on the surface of the wool are more or less fused together to a smooth surface, which would account for the great increase in lustre. The additional tensile strength is prob- ably accounted for by the same fact, the closer adhesions of the * Matthews, Jour. Soc. Chem. Ind. y vol. 21, p. 685. 48 THE TEXTILE FIBRES. scales giving a greater rigidity to the fibre. The volatile alkalies, such as ammonia and ammonium carbonate, do not have any marked deleterious effect on wool, especially at low temperatures; hence these compounds form excellent scouring materials. The hydroxides of the alkaline earths, though less violent in their action than the fixed caustic alkalies, nevertheless decompose wool. Milk of lime, even in the cold, abstracts most of the sulphur, and also causes the fibre to become hard and brittle if the action is prolonged ; the wool also loses its felting quality to a considerable extent. Barium hydroxide, as already noted, is used for the decomposition of wool in the preparation of lanuginic acid. Towards other chemical reagents wool is much more reactive than cotton, and either absorbs from solution or chemically com- bines with many substances. The fibre is quite readily oxidized when treated with strong oxidizing agents such as potassium permanganate or bichromate, becoming greatly deteriorated in its qualities. Towards chlorin wool acts in a peculiar manner; it is com- pletely decomposed by moist chlorin gas, but in weak solutions it absorbs a considerable amount of chlorin and is strangely altered in its properties.* It becomes harsh, f has a high lustre, and acquires a silk- like feel or "scroop," at the same time losing its felting properties, though its attraction for coloring-matters in general is largely increased. J * Bromin appears to have a similar action on wool. It is claimed to have the advantages over chlorin in that it does not turn the material yellow, and that in mixtures of dyed and undyed wool the former is not attacked. This latter statement is open to doubt. f According to a recent German patent, the harshness of chlorinated wool may be considerably lessened by working the material first in a solution of a salt such as citrate of zinc or acetate of iron, or of sodium stannate or aluminate; this is followed by a second bath of very dilute alkali, after which the goods are ex- posed to the air. The author, however, has not been able to obtain any satisfac- tory results on testing this process. I Chlorinated wool finds quite a number of applications in practice. The process is used, for instance, for the purpose of imparting a silk-like gloss to the fibre. Again, if yarns of chlorinated wool and ordinary wool are woven together in pattern, and the fabric afterwards fulled, since the chlorinated wool does not felt it will not shrink up like the remainder of the yarn, and in consequence the pattern will be brought out with very good effect; a great variety of novelties WOOL AND HAIR FIBRES. 49 W T ith neutral metallic salts wool does not seem very reactive, as it does not absorb them appreciably from their solutions. With salts, however, which are add in reaction and are capable of being easily dissociated, such as alum, ferrous sulphate, etc., the wool fibre possesses considerable attraction, especially when boiled in their solutions.* With regard to coloring-matters, wool is the most reactive of all the textile fibres, combining directly with acid, basic, and most substantive dyestuffs, and yielding, as a rule, shades which are much faster than those obtained on other fibres. There have been various opinions put forward as to the influence in dyeing of the active chemical groups in wool. If may be produced in this manner. Finally, the property of chlorinated wool to take up more dyestuff than ordinary wool, when dyed in the same bath, is also utilized; and fabrics with beautiful two-color effects may be easily obtained in this manner by weaving the chlorinated wool into designs with ordinary wool and afterwards dyeing with suitable coloring-matters. The chlorination of the woolen yarn is carried out in practice as follows: The material is well freed from all greasy matters by a preliminary scouring; this must be very thorough, otherwise good results will not be obtained, as the yarn is liable to finish up very uneven. A steeping in hydrochloric acid next takes place; the solution should be cold and have a density of i Tw. The wool should be left in this bath for twenty minutes. It is next passed into a solution of bleaching powder standing at 3 Tw. and worked for ten minutes, after which it is again treated with the solution of hydrochloric acid and washed thoroughly. It is said that sodium hypochlorite is better to use than chloride of lime, and sulphuric acid is preferable to hydrochloric, showing less tendency to turn the material yellow. The yellow color due to the chlorin may be removed by treatment with sulphurous acid. * Schellens (Arch. Pharm., 1905, p. 617) has furnished some interesting experi- ments showing the relative power of fixation of metallic salts possessed by vari- ous textile fibres. With solutions of ferric chloride, for instance, the following results were obtained: Solution No. i, Solution No. 2, containing containing i Per Cent of Iron, o.i Per Cent of Iron. Cotton-wool o.i 12 o.i 12 Filter-paper o. 23 o. 123 Vegetable silk i.oi 0.56 Jute 0.56 o . 44 Raw silk o . 67 o .67 Wool o . 84 o . 36 The figures refer to the weight of iron fixed by i gram of the fibre from 50 cc. of the respective solutions. 50 THE TEXTILE FIBRES. the phenomena of dyeing were principally of a chemical nature we would expect this influence to be a considerable one. In the case of acid and basic dyes, we have to deal with bodies possessing definite chemical characteristics; that is to say, acid dyes are acid in nature, while basic dyes have basic properties. From the facts already put forward that wool consists principally of an amido-acid, and is therefore capable of exhibiting both acid and basic properties, it would be natural to expect that in dyeing with acid coloring-matters there would be (to some degree at least) the formation S*f a compound between the acid of the dye- stuff and the base of the wool ; and likewise, in dyeing with basic coloring-matters the basic portion of the dyestuff would combine with the acid portion of the wool. That such a combination in reality does take can hardly be doubted, for many experimental facts have been adduced leading to such a conclusion. Aside from the fact that wool combines directly with acid and basic coloring-matters, it has also been shown * that when the active chemical groups in the fibre are neutralized by proper chemical treatment, the reactivity of wool towards acid and basic dyes re- spectively is much decreased. The acid nature of wool may be almost completely neutralized by acetylation with acetyl chloride, f and the resulting fibre shows but very slight reactivity towards basic dyes, and a correspondingly increased reactivity towards acid dyes. * Suida, Farber-Zeit., 1905. f Suida has found that when wool is heated with acetyl chloride at the tem- perature of the water-bath a copious evolution of hydrochloric acid takes place, indicating the formation of an acetyl compound. Wool which has been thus treated and freed from all excess cf the reagent by alternate rinsing with alcohol and water is found to have lost to a great extent its affinity for the basic color- ing-matters. Wool treated with acetic anhydride shows the same effect. Micro- scopical examination in both cases does not exhibit any structural modifications in the fibre. On heating wool which has been treated in this manner with a weak solution of ammonium carbonate (a reagent which is capable of saponify- ing acetyl compounds), the wool again regains its normal character with respect to its behavior towards basic dyestuffs. A change of the same character in wool is produced by heating the fibre on the water-bath with alcohol in the pres- ence of a small amount of strong sulphuric acid. This treatment also appears to form an ester which is saponified by treatment afterwards with an alkali, so that the wool regains its original condition. WOOL AND HAIR FIBRES. 51 If wool is left in a warm place in a moist condition so that the fibre does not have free access to plenty of fresh air, it, will soon develop a fungoid growth or mildew in spots. This causes the fibre to become tender and eventually rot. This fungoid growth will develop without any sizing ingredients or other for- eign matter being present on the fibre. It rapidly attacks the scales on the surface of the fibre, and then eats into the inner sub- stance of the wool. Under the microscope (see Fig. 16) this fungoid growth appears as two forms: (a) Small elliptical cells which adhere to the surface of the fibre and spread out from it; they seem to colonize especially * at the joints of the scales; (b) a a / tree-like growth consisting of several cells joined together and FIG. 16. Wool Fibres Attacked by branching off from one another; Mildew - < x 3-) these grow over the fibre as a a > fun g us growing in jointed cells, tree- i i / ri , ji like; b, fungus growing in isolated cells. kind of filmy integument, and do (Mic 8 rogr a P h by author.) not appear to corrode the wool as. rapidly as the first kind of cells. Mildew is especially apt to develop on woolen material which contains a small amount of alkali, the alkaline reaction probably being favorable to the growth of the fungus.* 3. Microchemical Reactions. The chemical reactions of the wool fibre under the microscope are not as characteristic as its physical structure. With concentrated hydrochloric or sulphuric acid the fibre gradually dissolves with a red coloration; with nitric acid it dissolves with much difficulty and with a yellow color; ammoniacal copper oxide causes the fibre to distend con- siderably with gradual disintegration, bringing the scale mark- ings into prominence; solutions of copper or ferric sulphate stain the fibre black. * Hence the tendency cf wool dyed in the indigo-vat to develop mildew stains. 52 THE TEXTILE FIBRES. 4. Hygroscopic Quality. Wool is more hygroscopic than any other fibre, but the amount of moisture it will contain will vary considerably according to the humidity and temperature of the surrounding atmosphere. Under average conditions, however, it will contain from 1 2 to 14 per cent, of absorbed moisture. The hygroscopic quality of wool is a subject of considerable importance in the commercial handling of this fibre, for the weight of any given lot of wool will vary within large limits in accordance with climatic conditions; that is to say, the shipment of wool from one locality to another of different humidity and temperature will cause a loss or gain in the apparent weight of the material. So important a factor has this become in the commercial relations between wool -dealers, that conditioning houses for wool have been established in many European centres for the purpose of carefully ascertaining the actual amount of fibre and moisture present in any given lot of wool, the true weight being based on a certain standard percentage of moisture, or so-called "regain." This percentage varies somewhat with the character of the material and also the conditioning house, ranging from 16 to 19 per cent. The hygroscopic quality of wool also has an important bearing on the spinning and finishing processes for this fibre, it being necessary to maintain a definite and uniform condition of moisture in order that the best results be obtained in the spinning of yarns and the finishing of the woven fabric. The wool fibre also appears to possess a certain amount of "water of hydration, which is no doubt chemically combined in some manner with the fibre itself; for it has been observed that wool heated above 100 C. becomes chemically altered through a loss of water at that tempera- ture. This will no doubt explain the fact that air-dried wool is superior in quality to that dried by means of artificial heat, which usually signifies a rather elevated temperature. According to Persoz, the destructive action of high temperatures on the wool fibre may be prevented by saturating the material with a 10 per cent, solution of glycerol, after which treatment the wool may be exposed to a temperature of 140 C. without being affected. The explanation of this action is no doubt to be found in the fact that glycerol holds water with considerable energy, and even WOOL AND HAIR. FIBRES. 53 at these elevated temperatures all of the moisture originally present in the wool is not driven out of the fibre. In order to economize time, it is sometimes necessary to dry wool rather quickly by the use of suitable machinery and high temperatures. Where a proper regulation of the temperature is possible, the wet wool may be subjected to quite a high degree of heat without injury, for the fibre itself does not become heated up, due to the rapid evaporation of the moisture. As the fibre becomes drier, however, it is important that the temperature fall, so that at the end of the operation, when the wool has become dried to its normal content of moisture, the temperature should be that of the atmosphere. Too much importance cannot be attached to the proper dry- ing of wool in all of its stages of manufacture, either in scouring, dyeing, washing, or finishing. If wool is overdried, that is, if the moisture in it is reduced to an amount much less than that which it would normally contain, inferior goods will always be the result, for the intrinsic good qualities of the fibre become greatly depreciated every time such a mistake is committed. The following table shows the percentage of moisture in air- dried wool and when exposed to an atmosphere saturated with moisture, as compared with the same values for other fibres: Fibre. Air-dry. Saturated. Fibre. Air-dry. Saturated. Wool 8-id 3O Manila hemp. . . 8-12 J.O Silk IO I 2 3O Tute. 6 2 3 Cdtton 6-8 2 I Flax H-8 I 3 Ramie e-3 18 5. Conditioning of Wool. In speaking of the hygroscopic quality of wool, it was mentioned that this fibre was capable of absorbing a considerable amount of moisture, and that this amount varied within rather large limits, depending upon the conditions of temperature and humidity of the air to which it may be exposed. It may be readily understood from these facts that in the buying and selling of wool and woolen goods upon a basis of weight, the question as ' to how much moisture is present becomes of great practical importance in determining the money value of the 54 THE TEXTILE FIBRES. operation. In England and on the continent of Europe, this fact has been recognized for some time, and there have been established at the various European wool-centres official labora- tories where the percentage of moisture in raw wool or in manu- factured woolen material is carefully ascertained, and the sales are based on the actual amount of normal wool fibre contained in the lot examined. These official laboratories * are called " con- ditioning houses," and the process of determining the amount of moisture in the wool is termed "conditioning." In the condi- tioning of wool the operation is carried out as follows: Repre- sentative samples are taken from the lot under examination; these are mixed together, and three test samples of \ to i Ib. each are taken. The test sample, after being carefully weighed, is placed in the conditioning apparatus and dried to constant weight at a temperature of io5-uoC. (220 F.). This weight repre- sents the amount of dry wool fibre present in the sample, the loss in weight represents the amount of moisture the wool contained. The amount of normal wool is obtained by adding to the dry weight of the wool the amount of moisture supposed to be present in the air-dried material under normal conditions of humidity and temperature. The added amount is termed "regain," and is officially fixed by the conditioning house. This permissible percentage of regain varies with the form of the manufactured wool; the conditioning house at Bradford,! England, for instance, has established the following figures : Per Cent. Wools , 16 Tops combed with oil. . , 19 Tops combed without oil i8J Noils 14 Worsted yarns i8J * The first official conditioning house was established at Lyons in 1805 for the conditioning of silk. f The system of conditioning adopted at Bradford is as follows: The weights of the packages and conditions are taken by three persons independently on sensitive scales which are adjusted weekly. These scales have a weighing capacity from one-half pound to ten tons. In making the tests for moisture, the samples are carefully selected from various parts of the packages. The amount of the material taken for this purpose is for wools, noils, and wastes, about two pounds from each package; for tops, three balls; for yarns in hank, about four pounds WOOL AND HAIR FIBRES. 55 The conditioning house at Roubaix, on the Continent, allows following percentages for regain on woolen materials:* Per Cent Wools I 4 Tops ' x8 Woolen yarns 17 The percentage of regain allowed at Bradford is considerably higher than would be indicated by the amount of moisture in woolen materials in the vicinity of Philadelphia. The author has found from many conditioning tests at the Philadelphia Textile School that woolen yarns will average about 10 per cent, of moisture, worsted tops (in the oil) and loose wool about 12 per cent., and woven fabrics of wool about 8 to 9 per cent. This would correspond to a regain on the dry weight as follows: Per Cent. Woolen yarns n.i Worsted tops and loose wool 13.6 Woolen cloth 9.9 in 1200 pounds; for yarns on bobbins or tubes, twenty to forty bobbins or tubes, and for yarns on cones, cheeses, etc., five to fifteen pounds. The standard regains and allowances are as follows: Wools and waste, for moisture, a regain of 16 per cent., equal to 2 ozs. 3^ drs. per Ib. Tops combed with oil, for moisture, a regain of 19 per cent., equal to 2 ozs. 9 drs. per Ib. Tops combed without oil, for moisture, a regain of i8 per cent., equal to 2 ozs. 7^ drs. per Ib. Ordinary noils, for moisture, a regain of 14 per cent., equal to i oz. 15$ drs. per Ib. Clean noils, a regain of 16 per cent., equal to 2 oz. 3^ drs. per Ib. Yarns, worsted, for moisture, a regain of i8J per cent., equal to 2 ozs. 7$ drs. per Ib. Yarns, cotton, for moisture, a regain of 8 per cent., equal to i oz. 4 drs. per Ib. Yarns, silk, for moisture, a regain of n per cent., equal to i oz. 9^ drs. per Ib. Cloths, worsted and woolen, a regain of 16 per cent., equal to 2 ozs. 3^ drs. per Ib. *The International Congress at Turin (1875) fixed the amount of "regain" for different textile fibres as follows: Silk ii per cent. Wool (tops) 18! Wool (yarn) 17 Cotton 8 Linen 12 Hemp 12 Jute I3f New Zealand hemp 13! 56 THE TEXTILE FIBRES. In order to give fair regains for commercial purposes, the author would recommend for woolen yarns a regain of n per cent., for tops and roving and loose wool, 15 per cent., and for wool cloth ii per cent. For silk the regain allowed should be n per cent., and for cotton and vegetable fibres in general the regain should be 7 per cent. In the United States Government specifications for army blankets, etc., of wool, a regain of n per cent, is allowed. The method of calculating the amount of normal wool may be illustrated by the following example: A lot of 1000 Ibs. of loose wool was submitted for conditioning; ten samples of i Ib. each were taken from different parts of the lot; these were mixed together and three samples of 250 grams each were taken for testing. On drying to constant weight the three samples lost, respectively, (i) 12.25 P er cent -> (2) 12.30 per cent, (3) 12.22 per cent., making the loss 12.26 per cent. Hence in the entire lot of 1000 Ibs. of wool there were 122.6 Ibs. of moisture or 1000 122.6 = 877.4 Ibs. of dry wool. The permissible amount of regain in this case was 1 5 per cent. ; hence the amount of normal wool would be (877.4X- J +877.4 = 1009 Ibs. instead of 1000 Ibs. The apparatus employed for the conditioning test is usually one of such a construction as to be especially adapted for the purpose. The form may differ somewhat in details with different makers, but a typical conditioning oven may be described as follows : The apparatus consists of an upright oven heated by a flame placed in the lower chamber. An even temperature is main- tained by so conducting the currents of heated air that they pass completely around the inner chamber or oven containing the sample to be tested (see Fig. 17). A thermometer projecting into the oven from above is employed for indicating the temperature, and this may be maintained at the desired point by a proper regu- lation of the supply of heat. The material to be conditioned, in whatever form (as loose wool, yarn, etc.), is placed in a wire basket suspended from one arm of a balance fixed outside and above the WOOL AND HAIR FIBRES. 57 oven; the weight of the basket and its contents is counterpoised by placing definite weights on a scale-pan suspended from the other arm of the balance. As the material diminishes in weight through the volatilization of its moisture, the loss is noticed from time to time by removing the necessary weights from the scale-pan FIG. 17. Conditioning Apparatus. in order to restore the equilibrium of the balance. When the weight becomes constant after heating at 110 C., the total loss is recorded, and this figure represents the amount of moisture which was originally present in the material tested. The balance is usually enclosed in a suitable case in order to protect it from draughts of air whereby its sensibility would be impaired. 58 THE TEXTILE FIBRES. Another form of conditioning apparatus of somewhat different shape is shown in Fig. 18. FIG. 18. Another Form cf Conditioning Apparatus. 6. Calculations Involved in Conditioning. In the condition- ing of wool (or of any other textile material), there are certain calculations necessary which it may be advisable at this point to explain. The two principal calculations to be made involve the determination of the percentage of moisture based on the weight of the material as taken for the test (that is, on its moist weight), and then the determination of the conditioned weight of the material based on a definite percentage allowance of "regain," this percentage being calculated on the dry weight of the material. The different problems in conditioning will now be taken up.* * See Persoz, Essai des Matures Textiles. WOOL AND HAIR FIBRES. 59 (i) If a weight (w) of material after drying shows a weight (a), what percentage (x) of moisture does it contain? iv a = loss in weight on drying = moisture. w w a = #, per cent, of moisture. (2) If a quantity of material of weigl t (w) contains x per cent, of moisture, what is its dry weight (a) ? a=iv\ i |. 100, (3) If from a weight (W) of material there is taken a sample of weight (w) and the dried weight of this is found to be (a), what will be the conditioned weight (C) of the material, allowing a regain of (R) per cent. ? The dry weight (-4) of the entire material will be A=WX-> w and the conditioned weight will be (4) A substance is conditioned with a regain of (R) per cent what percentage of moisture (x) does it contain? We have the proportion therefore ,00+* 6o THE TEXTILE FIBRES. The following table shows the percentage of moisture in any material corresponding to a definite percentage of regain. Per Cent. Regain. PerCent. of Moisture. Per Cent. Regain. Per Cent, of Moisture. 5 4-76 12 10.71 6 5-66 I2 -5 II. II 7 6-54 J 3 11.50 7-5 6.98 14 12.28 8 7-41 15 13 -4 8-5 7.83 16 J 3-79 9 8.26 17 14-53 10 9.09 18 I5-25 ii 9.91 J 9 J 5-97 20 16.67 (5) If a material contains (x) per cent, of moisture, what will be the corresponding percentage of regain (R) ? This is the reverse of the previous problem. We have R _ . 100 X The following table shows the percentage of regain of any material corresponding to a definite percentage of moisture. Per Cent, of Moisture. Per Cent. Regain. Per Cent, of Moisture. Per Cent. Regain. 5 5-26 !3 14.94 6 6.38 14 16.28 7 7-53 15 17.65 8 8.70 16 I9-05 9 9.89 T 7 20.48 10 ii. ii 18 2I -95 ii 12.36 19 23.46 12 13.64 20 25.00 (6) If a material is required to possess a definite conditioned weight (C), what percentage of regain (R) must be applied to the dry weight (a) ? We have the proportion C-a therefore 100 C-a WOOL AND HAIR FIBRES. 61 (7) If the dry weight (a) of any material is given, what quantity of water (q) would it have to absorb in order to con- tain (x) per cent. ? We have the proportion loo # a therefore - zoo-* The weight (W) of the material after absorbing the moisture would be o+q t Iooa or 100 (8) If the dry weight (a) of a material is given, what would be its conditioned weight (C), allowing (R) percentage of regain? We have in this case C-/i+ ) \ loo/ (9) If the conditioned weight (C) of a material is given with a percentage of regain (R), what is its dry weight (a) ? From the previous formula we have icoC loo+R' (10) If the percentage of moisture (x) is known in a material, what will be the conditioned weight (C), allowing a regain of (R) percent.? The dry weight (a) will be / x \ a i-- 1. V loo/ 62 THE TEXTILE FIBRES. Therefore the conditioned weight with (R) per cent, regain will be (n) If the original weight (W) of a material is known and also its conditioned weight (C), what percentage difference in weight (D) would there be between the original weight and the conditioned weight? We have the proportion W 100 W-C D ' ico(TF-C) therefore D = - -^ '-. There would be a gain or loss by conditioning according to whether (W) is greater or less than (C) . (12) If the conditioned weight (C) of a material is given and also its percentage difference (D) on conditioning, find the original weight (W) of the substance. From the previous formula we have IOOC loo D' (13) If the original weight (W) of a material is known and also the percentage difference (D) on conditioning, find the conditioned weight (C). From the previous formula we have W(ioo-D) 100 (14) If a material contains (x) per cent, of moisture, calcu- late the difference (d) between its original weight (W) and its conditioned weight (C) with a regain of (R) per cent. WOOL AND HAIR FIBRES. 63 This difference is d = W-C, and from the formula under (10) we have loo loo W[(ioo+R)x-iooR] hence d= - . 10,000 If (W) in this formula is taken as equal to 100, the expression becomes simplified to According to the value of (x) this difference will be positive or negative; that is to say, the material will lose or gain by condi- tioning. looR x is greater than -~ there will be a loss. T . looR If #=~ T5 IOO+-R the fibre will be in its conditioned state. Finally, if x is less than ~ the material will gain in weight by conditioning. (15) If the difference (d) between the original weight (W) of a material and its conditioned weight (C) at a regain of (R) per cent, is known, find the percentage of moisture (x) in the material. 64 THE TEXTILE FIBRES. This is the reverse of the preceding problem and may be solved by taking the reciprocal of the formula for (d), as follows: _ioo(WR + W(ioo+R) If we take the original weight as equal to 100 and call (D) the corresponding difference, the expression becomes ioo(R+D) loo+T? ' It is necessary to remember in these formulas that the value of (d) or (D) is positive only if the original weight is greater than the conditioned weight; if the contrary is the case, the difference will be of a negative value. For example, a sample of wool loses 2 per cent, on conditioning at 15 per cent, regain; hence it contains 100(15+2) ; =14.7 per cent, moisture, 100 + 15 whereas if it gains 2 per cent, in weight by conditioning, we have 100(15-: 100 + 15 = 11.3 per cent, moisture. (16) A sample of material shows a difference in weight of (D) per cent, on conditioning at (R) per cent, regain, what dif- ference (D r ) would there be if conditioned at a regain of (R') per cent. ? If we call the dry weight (a), then = ioo a[i H - \ loo = ioo-a(i + ). \ loo/ WOOL AND HAIR FIBRES. 65 Hence, by eliminating (a), we have (ioo+IV)D-ioQ(R'-R) ico+R This problem will often arise in practice where two different sets of regains are to be allowed. For example, a sample of wool conditioned at a regain of 15 per cent, loses 0.4 per cent, in weight, how much would it lose if the regain allowed was 17 per cent.? (117X0.4) -(100X2) D' = y - 2L- -^=-1.3 per cent.; that is to say, the fibre would gain 1.3 per cent, in weight. (17) A sample of material on conditioning at a regain of (R) per cent, shows a loss of (D) per cent., what regain would have to be adopted in order that the loss may be (D r ) per cent. ? From the previous formula we have ioo(D + R) -D'(ioo+R) R f;; . 100 -D (18) If the conditioned weight (C) at a regain of (R) per cent, is known, calculate the conditioned weight (C') at a regain of (R f ) per cent. From the formula under (8) we have C loo+R . ^100 + ^' hence C' = ( (19) In a textile material consisting of two kinds of fibres, if the percentage conditioned amounts of the two fibres are known, (C) and ((7), and their respective regains are (R) and 66 THE TEXTILE FIBRES. (R') t what will be the average regain (r) and the average amount of moisture (x) in the mixture ? If (C) and (CO are the conditioned weights of the two fibres, their dry weights (A) and (A') would be iooC iooC' and A' 100 + R the average moisture would be iooC iooC' VIC C' \\ hence #=ioo|i (- The average regain would be IOOX IOOX For example, suppose we have conditioned a yarn composed of 65 per cent, of wool and 35 per cent, of cotton, with respective regains of 15 and 7 per cent. Then [/ 65 .35 \~| \ii5 1077 _T #=9.6 per cent, moisture, r=io.6 per cent, average regain. (20) In a textile of mixed fibres if the proportion (P) and (P') of the two fibres is known on the dry weight (A), together with WOOL AND HAIR FIBRES. 67 the moisture (x) lost on drying, what would be the conditioned weight (C) of the material, allowing (R) and (R f ) respectively as the regains for the two fibres? We have p A = amount of first fibre, 100 P' A = amount of second fibre, and (PA R \ PA - X- - I + = conditioned weight of first fibre. 100 IOO/ IOO I P'A R' \ P'A X ) + = conditioned weight of second fibre. Vioo loo/ loo Adding these two terms gives us / PR + P'R'\ A [ i + - 1 = conditioned weight of entire material. \ 10000 / For example, suppose a yarn contains 60 per cent, of wool and 40 per cent, of cotton on a dry weight of 85 Ibs., allowing respective regains of 15 and 7 per cent., what would be the conditioned weight of the yarn? 68 THE TEXTILE FIBRES. TABLE SHOWING THE CONDITIONED WEIGHT OF 100 LBS. OF ANY MATERIAL WITH REGAINS OF 7, n, AND 15 PER CENT., CONTAINING DIFFERENT AMOUNTS OF MOISTURE. Per Cent. Moisture. Conditioned Weight, Regains. PerCent. Moisture. Conditioned Weight, Regains. Per Cent. ii Per Cent. Per Cent. 7 Per Cent. II PerCent. Percent. 5- 101.65 105.45 109.25 9-7 96.62 100.23 103.84 .1 101.54 105-34 109.14 .8 96.51 100.12 I0 3-73 .2 101.44 105.23 109.02 9 96.41 100.01 103.61 3 iQi-33 105. 12 108.91 IO.O 96.30 99.90 103.50 4 IOI.22 I05.OI 108.79 . i 96.19 99-79 103.38 .5 101 . 12 104.90 108.68 . 2 96.09 99.68 103.27 .6 101 .OI 104.78 108.56 3 95-98 99-57 103.16 7 100.90 104.67 108.45 4 95-87 99.46 103.04 .8 lOO.So 104.56 108.33 5 95-77 99-34 102.93 9 100.69 104.45 108.22 .6 95.66 99-23 102.81 6.0 100.58 104.34 108. 10 7 95-55 99.12 102.70 .1 100.48 104.23 107.99 .8 95-45 99-oi 102.58 .2 100.37 104.12 107.87 9 95-34 98.90 102.47 3 100.26 IO4.0I 107.76 II. 95- 2 3 98.79 102.35 4 100. 15 103.90 107 . 64 . i 95 - 12 98.68 102.24 .5 100.05 103.79 107-53 .2 95.02 98.57 IO2.I2 .6 99-94 103.67 107.41 3 94.91 98.46 IO2.OI .7 99-83 103.56 107.30 4 94.81 98.35 101.89 .8 99.72 I0 3-45 107. 18 5 94.70 98-23 101.78 9 99.62 103-34 107.07 .6 94-59 98.12 101.66 7.0 99-5 1 103.23 106.95 -7 94.48 98.01 101-55 . i 99.40 103.12 106.84 .8 94-37 97.90 101.43 . 2 99-3 103.01 106.72 9 94.27 97-79 101.32 3 99.19 102.90 106.61 12. O 94.16 97.68 IOI.2O .4 99.08 102.79 106.49 . I 94-05 97-57 IOI.O8 .5 98.98 102.68 106.38 .2 93-95 97.46 100.97 .6 98.87 102.56 106.26 3 93-84 97-35 100.85 .7 98.76 102 . 45 106. 15 4 93-73 97-24 100-74 .8 98.66 102.34 106.03 5 93.62 97.12 100.62 9 98.55 102.23 105.92 .6 93-5 2 97.01 100.51 S.o 98.44 IO2. 12 105 .80 7 93-4i 96.90 100.39 .1 98.34 IO2.OI 105.69 .8 93-3 96.79 100.28 .2 98.23 IOI.9O 105-57 9 93.19 96.68 100. 16 .3 98.12 101.79 105 .46 13.0 93-09 96.57 100.05 -4 98.01 101.68 105.34 . i 92.98 96.46 99-94 5 97.90 101.57 105-23 .2 92.88 96.35 99.82 .6 97.80 101.45 105. ii 3 92-77 96.24 99.71 7 97.69 101.34 105.00 4 92.66 96.13 99-59 .8 97-58 101.23 104.88 5 9 2 -55 96.01 99.48 9 97.48 IOI.I2 104.77 .6 92-45 95-90 99-36 9.0 97-37 IOI.OI 104 . 65 7 92-34 95-79 99-25 . i 97.26 IOO.9O 104-53 .8 92-23 95-68 99 - J 3 .2 97.16 100.79 104.42 9 92. 12 95-57 99.02 3 97 -5 100.68 104.30 14.0 92.O2 95-46 98.90 4 96.94 100.57 104.19 . i 91.91 95-35 98.78 .5 96.84 100.46 104.07 .2 9I.8I 95-24 98.67 .6 9 6 -73 100. 34 103.96 3 91.70 9S- I 3 98-56 WOOL AND HAIR FIBRES. 6 9 TABLE SHOWING THE CONDITIONED WEIGHT (Contimted}. Per Cent. Moisture. Conditioned Weight, Regains. Per Cent. Moisture. Conditioned Weight Regains. Per Cent. ii Per Cent. Per Cent. Per Cent PerCent. PerCent. 14.4 9I-S9 95.02 98.44 I 7 .8 87-95 91.24 94-53 5 91.49 94.90 98.33 9 87.85 Q 1 -^ 94.42 .6 91.38 94-79 98.21 18.0 87.74 91 .02 94-3 7 91.27 94.68 98.10 . i 87-63 90.91 94.18 .8 91. 16 94-57 97.98 .2 87-52 90.80 94.07 9 9 I -5 94.46 97.87 3 87-42 90.69 93-96- JS- 9 -95 94-35 97-75 4 87-3I 90.58 93.84 .1 90.84 94.24 97.64 5 87.21 90.46 93-73 .2 90.74 94.13 97-52 .6 87.10 9 -35 93.61 3 90.63 94.02 97.41 7 86.99 90.24 93-5 4 90.52 93-9 1 97.29 .8 86.88 90.13 93.38 5 90.42 93-79 97.18 9 86.78 90.02 93-27 .6 9Q-3 1 93.68 97.06 19.0 86.67 89.91 93 !$ 7 90.20 93-57 96.95 .1 86.56 89.80 93 -4 .8 90.09 93-46 96.83 .2 86.45 89.69 92.92 9 89-98 93-35 96.72 3 86-35 89-58 92.81 16.0 89.88 93- 2 4 96.60 4 86.24 89.47 92.69 . i 89.77 93 - J 3 96.48 -5 86.13 89-36 92.58 .2 89.67 93.02 96.37 .6 86.02 89.24 92.46 .3 89.56 92.91 96.26 7 85.92 89.13 92-35 4 89-45 92.80 96.14 .8 85.81 89.02 92-23 5 89.34 92.68 96.03 9 85 -7 1 88.91 92.12 .6 89.24 9 2 -57 95 -9 1 20. o 85.60 88.80 92.00 7 89.13 92.46 95.80 . i 85-49 88.69 91.88 .8 89.02 92-35 95-68 .2 85 38 88.58 91.77 9 88.92 92.24 95-57 3 85.28 88.47 91.66 17.0 88.81 92.13 95-45 4 85-17 88.36 9 I -54 .1 88.71 92.02 95-34 5 85.06 88.25 9J-43 .2 88.60 91.91 95- 2 2 .6 84-95 88.13 9L3 1 3 88.49 91.80 95- 11 7 84-85 88.02 91.20 4 88.38 91.69 94-99 .8 84.74 87.91 91.08 5 88.28 9 r -57 94.88 9 84.63 87.80 90.97 .6 88.17 91.46 94.76 21. 84-53 87.69 90-85 7 88.06 9 I -35 94.65 CHAPTER IV. SHODDY AND WOOL SUBSTITUTES. I. Varieties of Shoddy. Besides the natural varieties of wool which find applications in the textile industries we have a large quantity of recovered wool employed as a textile fibre. This is obtained by tearing up woolen rags and waste, converting it back into the loose fibre and spinning it over again, either alone or in admixture with varying proportions of pure fibre or fleece- wool. This artificial wool, or wool substitute, as it is frequently called, is also obtained from rags and waste containing wool and cotton, or even silk; the vegetable fibre being destroyed by chemical treatment, leaving the animal fibre to be extracted and used again. On this account it is sometimes known as extract wool. The industry of converting recovered fibre into yarns and fabrics has assumed of late enormous proportions, and nearly all cheap woolen goods contain a high percentage of these wool substitutes in their composition. Depending on its source of production, this recovered wool will vary largely in its quality, and according to its origin and nature it is classed under several names, chief among which are the following: (a) Shoddy. Though this name is frequently applied to all manner of recovered fibre, it is more specifically used to desig- nate that which is derived from all-wool rags or waste which have not been felted, also from knit goods. This yields the best qual- ity of fibre, the average length of which is about one inch. In many cases it is almost equal in quality to a fair grade of fleece- wool, and is used in the production of many high-grade fabrics. (b) Mungo refers to the fibre obtained from woolen material which has been fulled or felted considerably, to disintegrate the 70 SHODDY AND WOOL SUBSTITUTES. 71 rags the fibres must be torn apart, and consequently it yields fibres of shorter staple and less value than the preceding. (c) Extract wool is that obtained from mixed wool and cotton rags and waste, and has to undergo the process of carbonization, whereby the vegetable fibre is destroyed.* It is sometimes called alpaca, and varies much in its length of staple and other qualities. Besides these well-known varieties of recovered wool there are a number of others to be met with in commerce, such as Thibet wool, which is usually obtained from light-weight cloth clippings and waste. Cosmos fibre is a very low-grade material, usually con- taining no wool at all, being made by converting flax, jute, and hemp fabrics back to the fibre. f Even the short down obtained in the shearing of woolen cloths is used, it being employed as a filler. The process of using it is called "impregnating," and con- sists in fulling the short waste into the cloth on the under side. 2. Examination of Shoddy. Woolen fibres consisting of shoddy usually offer a very characteristic appearance under the microscope, sufficient, at least, to distinguish them from fibres of new wool. A sample of shoddy generally shows the presence of other fibres besides wool, and fibres of silk, linen, and cotton are frequently to be observed (Fig. 19). Also, the colors of the different woolen fibres present are frequently quite varied, so that shoddy usually presents a multi-colored appearance under the microscope. A very striking appearance, also, is the simultaneous occurrence of dyed and undyed fibres; the diameters of the fibres will also vary between large limits, the variation in this respect being much more than with fleece wool. Some samples of shoddy will also show a large number of torn and broken fibres, and usually the external scales are rougher and more prominent. * This process is generally carried out by steeping the rags in a solution of sulphuric acid (6 1 w.) at 140 to 180 F. and then drying, whereupon the vege- table fibres are decomposed and are easily dusted out by willowing, the wool fibres being scarcely affected. The excess of acid is then removed by treat- ment with soda-ash and washing The fibres obtained are sometimes over one inch in length. t Peat fibre is a product obtained from partially decomposed peat. It is mixed with wool for yarns to be used in the manufacture of horse-cloths, mats, etc. Wood-wool is a somewhat similar product obtained from the long bleached fibres of wood. 72 THE TEXTILE FIBRES. It must be borne in mind, however, that pure wool may also show the presence of small quantities of vegetables fibres at times. These often arise from the occurrence of burrs (bristly and barbed seeds of various plants) in the original fleece. South American wools are especially liable to contain such burrs; in many cases these are incompletely removed, and may ultimately appear even FIG. 19. Microscopic Appearance of Shoddy, showing the varied Character of the Fibres. (X35o.) (Micrograph by author.) in the woven cloth. This frequently explains the existence of short fibres or vascular bundles of vegetable matter in cloth. Isolated fibres of woody tissue and cotton may also accidentally creep in through a variety of causes. According to Hohnel, samples of pure wool may easily contain as much as | per cent, of vegetable fibre. The latter authority also states that the vege- table fibres of shoddy, as a rule, are removed by carbonizing; hence the absence of cotton, linen, etc., must not be taken as a criterion to distinguish between pure wool and shoddy. When, SHODDY AND WOOL SUBSTITUTES. 73 however, cotton (always dyed) or cosmos fibre occurs in at least a quantity of one per cent., this may be taken as a direct indica- tion of the presence of shoddy, as it would scarcely ever happen that pure wool is adulterated with cotton; this only happens by admixture with shoddy W T OO!. Undyed cotton, unless present in considerable amount, cannot be considered as a suspicious com- ponent. The determination of the length of staple is also a rather unre- liable indication as to the presence of shoddy, for there are vari- eties of shoddy wools which are longer in staple than many fleece- wools; and also woven goods, though composed entirely of fleece-wool, may show the presence of a large number of short fibres caused by the shearing of the surface of the cloth, and by the tearing of the fibres in heavy fulling. Where woolen cloth has been impregnated or filled with short fibres obtained from clippings, such may usually be recog- nized by teasing the sample out with a stiff bristle- brush. Good cloth should not yield over J per cent, of clipped fibres from both sides. When the amount of such fibres is at all considerable, they may be used as serviceable material to test microscopically for shoddy, as they are most likely to be made up of this character of wool. Fine fleece-wools hardly ever show the absence of epidermal scales (though this is frequently the case with coarse wools); hence if examples of such fine wools are found showing a lack of epidermis, it may usually be taken as an indication of shoddy. Hohnel, however, calls attention to the fact that the following conditions previous to the manufacturing process itself have con- siderable influence on the good structure and integrity of the wool fibre: badly cut staple, lack of attention in raising the sheep, poor pasturage, sickness of the animal, the action of urine, snow, rain, dust, etc., packing the wool in a moist condition, rapid and frequent changes of moisture and temperature, the use of too hot or too alkaline baths in scouring, scouring with bad deter- gents, etc. These influences may lead to the partial removal of the epidermis, and to the softening and breaking of the ends of the fibre. There must also be considered the influence of wil- 74 THE TEXTILE FIBRES. lowing, carding, combing, spinning, weaving, gigging, fulling, acidifying, washing, shearing, pressing, etc., from which it is easy to understand why even fibres of fleece-wool may show the entire absence of epidermis. Hohnel also criticises other alleged char- acteristics of shoddy, such as torn places in the fibre, uneven- ness in diameter, etc., claiming that these can hardly be taken as an indication of shoddy, because such marks are often regu- larly present in many fleece-wools. Most samples of shoddy, in fact, show scarcely any structural differences from ordinary fleece- wool. The ends of shoddy fibres, however, usually present a torn appearance ; at least there is a great predominance of such fibres in shoddy, whereas in fleece-wool this appearance is seldom to be observed, the end of the fibre being cut off sharply. The appearance of the torn fibres may be easily observed under the microscope; the epidermis being entirely torn away, as well as the marrow which is sometimes present, while the fibrous cortical layer is frayed out like the end of a brush. This appearance can usually be rendered more distinct by previously soaking the fibres in hydrochloric acid. Sheared fibres are recognized by being very short and by having both ends sharply cut off. The color of the fibres is also a characteristic appearance of shoddy, as the majority of shoddy is made up of variously colored wools. It is of rare occurrence that rag-shoddy possesses a single uniform color. Hence if a sample of yarn, possessing a single average color, on examination reveals the presence of variously colored fibres, it is almost a positive indication of shoddy. In this connection it must not be forgotten, however, that fre- quently differently colored wools are mixed together previous to spinning, to make so-called "mixes." As a rule, however, only two to three colors are used together; therefore a purposely mixed yarn of this description is not likely to be confounded with a shoddy yarn where individual fibres of a large number of colors are nearly always shown. CHAPTER V. MINOR HAIR FIBRES. 1. The Minor Hair Fibres. Besides the fibre obtained from the domestic sheep, there are large quantities of hair fibres em- ployed in the textile industries and obtained from related species of animals, such as goats, camels, etc. As these are all more or less utilized in conjunction with wool itself, and are subjected to similar operations in manufacturing, it will not be out of place to consider them at this point. The chief among these related fibres are mohair, cashmere, alpaca, cow-hair, and camel-hair. 2. Mohair. This fibre is obtained from the Angora goat, an animal which appears to be indigenous to western Asia, being largely cultivated in Turkey and neighboring provinces. The fleece is composed of very long fibres, fine in staple, and with little or no curl. The fibre is characterized by a high silky lustre. Mohair is now grown to a considerable extent in the Western States, principally Oregon, California, and Texas, the goats having originally been imported from Turkey; there is also a large quantity of mohair grown in Cape Colony. The principal mohair clips (1902) are as follows: Turkey 8,500,000 Ibs. Cape Colony 7,500,000 ' ' United States 1,250,000 ' ' The principal use of mohair is for the manufacture of plushes, braids, fancy dress fabrics, felt hats, and linings. The charac- ter of fabric in which it may be employed is rather limited on account of the harsh wiry nature of the mohair fibre, and the fact that it will not felt to any degree. Domestic mohair (Ameri- 76 THE TEXTILE FIBRES. can) has only about two-thirds of the value of the foreign fibre; mohair in general has quite a large amount of kenipy fibre (which will not dye), but the domestic variety contains about 15 per cent, more kemp than the foreign, hence the lower value of the former. Another reason for this lessened value is that foreign mohair always represents a full year's growth (the fibres being 9 to 12 ins. in length), whereas a great deal of domestic mohair is shorn twice a year. This is especially true of that grown in Texas; the hair commences to fall off the goats in that district if allowed to grow for the full year. In judging of the quality of mohair, the length and lustre are of more value t than the fineness of staple. The finest grades of domestic mohair come from Texas, that from Oregon and California being larger and coarser. In Oregon the fleece is grown for a full year, and consequently the fibre is very long. The average weight of the fleece from Oregon goats is 4 Ibs., while in Texas it is only z\ Ibs. Foreign mohair varies much in quality, depending upon the district in which it is grown ; as a rule, the finer varieties are shorter in staple, the finest being about 9 ins. in length. Foreign mohair can be spun to as high a count as 6o's, whereas the finest quality of domestic mohair can only be spun to as high as 4o's. The coarsest varieties of mohair are used in carpets, low-grade woolen fabrics, and blankets. Microscopically, the mohair fibre is possessed of the following characteristics: The average length is about 18 cm., and the diameter about 40 to 50 //, and very uniform throughout the entire length (see Fig. 20). The epidermal scales can only be observed with difficulty, as they are very thin and flat, though regular in outline. They are also very broad, a single scale frequently surrounding the entire fibre; the edge of the scale is usually finely serrated. The best grades of fibres show no medulla, but there are usually to be found (especially in domestic mohair) coarse, thick fibres possessing a broad medullary cylinder, thus resem- bling the structure of ordinary goat- hair, from which, however, they are to be distinguished by being more slender and more uni- form in their diameter. Longitudinally, the fibre exhibits coarse, fibrous stria tions, approximating the appearance cf broad and regularly occurring fissures. Due to the fact that the surface scales MINOR HAIR FIBRES. 77 lie very flat and do not project over one another, the edge of the fibre is very smooth, showing scarcely any serrations at all, which accounts for its utter lack of felting qualities. The outer end of the fibre is either slightly swollen or blunt, but never pointed. When viewed under polarized light the fibres occasionally show the presence of a medullary canal, which appears as a hollow space, giving an illumination somewhat resembling that of a FIG. 20. Mohair Fibres. (X35O.) (Micrograph by author.) bast fibre, and covering from one-fourth to one-half of the diameter. 3. Cashmere is remarkable for its softness, and is much used in the woolen industry for the production of fabrics requiring a soft nap. Cashmere is the fibre employed in the manufacture of the famous Indian shawls. There are two qualities of cashmere wool, the one consisting of the fine, soft down- hairs and the other of long, coarser beard-hairs. The former are from ij to 3 J ins. in length and 13 p in diameter, while the latter are from 3 J to 4j ins. in length by 60 to 90 fi in diameter. The wool- hairs show 7 THE TEXTILE FIBRES. visible scales but no definite medulla, whereas the beard- hairs possess a well-developed medulla. The cortical layer is coarsely striated and shows characteristic fissures. At the point of the fibre the epidermal scales are either entirely absent or are so thin as to be scarcely visible. The fibre is very cylindrical; the scales have their free edge finely serrated, and the edge of the fibre also presents the same appearance. Besides mohair and cashmere, the hair of the ordinary goat is also used at times. It has the following characteristics (Hohnel) : FIG. 21. Wool-hairs of Cashmere. (X35 2 5 Chrysalis alone 66,300 Butterflies, half of each sex 99> 86 5 Thus we see that in less than forty days the weight of the silkworm increases almost 10,000 times. When the worm has reached the limit of its growth, it ceases * The length of time occupied in these different ages approximates as follows: ist, from birth to first moult, 5 to 6 days, ad, from first to second moult, 4 days. 3d, from second to third moult, 4 to 5 days. 4th, from third to fourth moult, 5 to 7 days. 5th, from fourth moult to maturity, 7 to 12 days. 9 6 THE TEXTILE FIBRES. to eat, and commences to diminish in size and weight. The time is now ready for the spinning of its cocoon; the worm perches on the twigs so disposed to receive it and exudes a viscous fluid from the two glands in its body wherein the silk secretion is formed. The liquid flows through two channels in the head of the worm into a common exit- tube, where also flows the secre- tion of two other symmetrically situated glands which cements the two threads together. Consequently, the thread of raw silk is produced by four glands in the worm; the two back ones secrete the fibroin which gives the double silk fibre, while the two front glands secrete the silk-glue or sericin which serves as an FIG. 33. Cross-section of Silk-cocoon. a, silkworm at completion of cocoon; &, after development of chrysalis with cast- off skin of larva beneath. integument and cementing substance.* On emerging from the spinneret in the head of the worm the fibre coagulates on con- tact with the air.f The worm weaves this thread around itself, layer after layer, until the cocoon or shell is gradually built up.J It requires about * According to Bolley the glands in the silkworm which secrete the fibre- producing liquids contain only glutinous, semi-fluid fibroin without admixture with sericin, the latter compound being a product of the subsequent oxidaticn of the fibroin by the air. f The contents of the glands of the silkworm have been the subject of study in a peculiar manner by Chappe. He triturated the glutinous matter with about one-third its weight of water, and thus obtained a liquid from which he was en- abled to blow variously shaped vessels of a very permanent character. (Ann. de Chim., vol. n, p. 113.) J First a net is formed to hold the cocoon which is to be spun, then the regu- SILK: ITS ORIGIN AND CULTIVATION. 97 three days for the completion of the cocoon. After finishing the winding of its cocoon, the enclosed silkworm undergoes a remark- able transformation, passing from the form of a caterpillar into an inert chrysalis or pupa, from which condition it rapidly devel- ops into a butterfly, which then cuts an opening through the cocoon and flies away.* As the integrity of the cocoon-thread would be destroyed by the escape of the butterfly and hence lose much of its value, it is desirable that the development of the chrys- alis be stopped before it proceeds too far, and this is accomplished FIG. 34. The Silk-moth, T - \CO NH/ The decomposition of fibroin by saponification with potash would then be / *< \ NH CO /NH 2 - = CO NH/ \CO.OK I Vignon prepared pure fibroin in the following manner: A lo-gram skein of raw white silk is boiled for thirty minutes in a solution of 15 grams of neutral soap in 1500 c.c. water; rinse in hot, then in tepid water; squeeze and repeat the treatment in a fresh soap-bath; rinse with water, then with dilute hydrochloric acid, again with water; finally, wash twice with 90 per cent, alcohol. The fibroin thus obtained leaves only o.oi per cent, of ash on ignition. (Compt* rend., vol. US. PP- i7 6l 3-) According to Allen, raw commercial silk from the mulberry silkworm is generally regarded as containing n per cent, of moisture, 66 per cent, of fibroin, 22 per cent, of sericin, and i per cent, of mineral and coloring-matters. (Comm. Org. Anal, Vol. 4, p. 506.) CHEMICAL NATURE AND PROPERTIES OF SILK. 119 Mulder (see above) of 53.35 per cent, was obtained by boiling the raw silk with acetic acid. By the action of a 5 per cent, solution of cold caustic soda, Stadeler obtained 42 to 50 per cent, of fibroin. Cramer obtained 66 per cent, by heating raw silk in water at 133 C. under pressure. Francezon reports 75 per cent, of fibroin by twice boiling the silk in a solution of soap and then treating with acetic acid. Vignon, by carefully purifying the fibroin by suitable treatment, obtained 75 per cent.* Unlike keratin, the proteid of wool, fibroin contains no sul- phur, and is much more constant in its composition. The empiri- cal formula for fibroin as given by Mulder is CisH^sNsOe. Mills and Takamine give the formula as C24H 38 N8O 8 , while Schiitzen- berger gives C 71 HI 07^4^)2 5. Cramer arrives at the same formula as Mulder, while Richardson (Jour. Soc. Chem. Ind., vol. 12, 426) gives CeoHgiNisC^s. Vignon's formula for specially purified fibroin is C22H47NioOi2.f The presence of the amido-group in fibroin has been shown, as in the case of wool (see page 41), by diazotizing the fibre with an acid solution of sodium nitrite, then washing and treating with solutions of various developers, such as phenol, resorcinol, alpha- and beta-naphthols, etc., whereby the fibre becomes dyed in different colors. From its action towards alcoholic potash Richardson con- cludes that silk fibroin is probably an amido-anhydride rather than an amido-acid. When boiled for a long period with * According to Fischer and Skita (Zeitschr. j. phys. Chem., vol. 33, p. 171, and vol. 35, p. 224), even technically purified silk still contains about 5 per cent, of silk-glue. f Silbermann found that fibroin heated with a solution of barium hydrate under pressure was decomposed with the formation of oxalic, carbonic, and acetic acids, together with an amido-body approximating the formula C^H^i^i O 43 * The latter compound is said to undergo further decomposition with the formation of tyrosin, glycocin, alanin, amido-butyric acid, and an amido-acid of the acrylic series. Fischer and Skita (Zeitschr. /. physiol. Chem., vol. 33, p. 177) have shown that in all probability amino-valerianic acid, C 8 H y .CH(NH 2 ).COOH, occurs in fibroin. Silk fibroin, however, appears to differ from other albumins in not con- taining aspartic acid, COOH.CH 2 .CH(NH 2 ).CO.OH. Glutaminic. acid, OOH.CH 2 .CH 2 .CH(NH 2 ) .COOH, also appears to be present in fibroin, though Hscher doubts this. 120 THE TEXTILE FIBRES. dilute sulphuric acid, fibroin is dissolved to a yellowish-brown liquid, leaving as a residue only a small amount of what is appar- ently a fatty acid. From this decomposition product Weyl (Ber., vol. 21, 1529) succeeded in isolating 5.2 per cent, of tyrosin, 7.5 per cent, of glycocin, and 15 per cent, of a crystalline com- pound which was apparently alpha-alanin. Towards Millon's and Adamkiewitz's reagents fibroin gives the usual reaction of pro- teids, and it also gives the biuret test.* According to Richardson, silk fibroin will absorb 30 per cent, of iodin when treated with HiibPs reagent. Attempts have been made to acetylize fibroin, but without success. | Fibroin is insoluble in ammonia and solutions of the alka- line carbonates; neither is it dissolved by a i per cent, solution of caustic soda, but stronger solutions affect it, especially if hot. From its solution in caustic soda fibroin may be reprecipitated by dilution with water. Fibroin is also soluble in hot glacial *, Millon's reagent consists of a solution of mercurous nitrate containing nitrous acid in solution. It is prepared by treating i c.c. of mercury with 10 c.c. of nitric acid (sp. gr. 1.4), heating gently until complete solution is effected, then diluting the solution with twice its volume of cold water. When a solution of a proteid is treated with this reagent, a white precipitate is first formed, which turns brick- red on boiling; a solid proteid becomes red when boiled with the reagent. Adam- kiewcz's test is to dissolve the proteid in glacial acetic acid, and then add con- centrated sulphuric acid to the solution, when a fine violet color will be produced, and the liquid will exhibit a faint fluorescence. The biuret test is to add a few" drops of a dilute solution of copper sulphate to the solution of proteid; on then adding an excess of caustic soda solution the precipitate which at first formed will be dissolved with the production of a fine violet coloration. f Cohnheim, in his tables of the percentage composition of various albumins > gives the following for the fibroin of silk: Per Cent. Glycocoll 36 Alanin 21 Leucin 1.5 Phenylalanin 1.5 a-Pyrrolidin-carboxylic acid 0.3 Serin 1.6 Tyrosin 10 Arginin i The occurrence of the following compounds in indeterminate amounts is also given: Lysin, histidin, tryptophane, and amino-valerianic acid. CHEMICAL NATURE AND PROPERTIES OF SILK. 121 acetic acid, and in strong hydrochloric, sulphuric, nitric, and phosphoric acids. Alkaline solutions of the hydroxides of such metals as nickel, zinc, and copper also dissolve fibroin. If silk fibroin is dissolved in cold concentrated hydrochloric acid, and the solution be allowed to stand sixteen hours at the ordinary temperature with three times its volume of hydro- chloric acid ( sp. gr. 1.19), it will no longer be precipitated by the addition of alcohol. The fibroin appears to have suffered hy- drolysis, being converted into a body similar to peptone. This substance may be separated out by steaming the above solution under diminished pressure.* If its aqueous solution be neutral- ized with ammonia and some trypsin ferment be added, tyrosin will begin to crystallize out in a few hours. Sericin, according to the analysis of Richardson, has the following composition: Per Cent. Carbon ....................................... 48. 80 Hydrogen ..................................... 6.23 Oxygen ....................................... 25 .97 Nitrogen ...................................... 19 . oo and its formula is given as CieH^NsOg. It is considered by some as an alteration product of fibroin; strong hydrochloric acid is said to convert the latter into sericin ; the conversion is supposed to take place by assimilation of water and oxygen. Fibroin Sericin Sericin may be obtained, in a pure condition by first boiling a sample of raw silk in water for several hours, after which the * Fischer and Abderhalden (Berichte, 1906, p. 752) have succeeded in isolating from the hydrochloric acid solution of silk fibroin a dipeptide in the form of methyl- diketopiperazine, having the formula /CH 2 .CO\ NH. [ \ > \CO.CH < \r The yield is about 12 per cent., and the product is identical with that obtained synthetically from glycocoll and J-alanin. 122 THE TEXTILE FIBRES. sericin is precipitated by lead acetate.* On treatment with dilute sulphuric acid, sericin yields a small quantity of leucin and tyrosin, but no trace of glycocoll, the principal product formed being a crystalline body called seri n, which appears to /NH 2 ' have the formula CzR^S , and from its chemical reactions X COOH is evidently analogous to glycocin, probably being amido-glyceric acid. Sericin is soluble in hot water, hot soap solutions, and dilute caustic alkalies. The aqueous solution is precipitated by alcohol, tannin, basic lead acetate, stannous chloride, bromin, and iodin, and by potassium ferrocyanide in the presence of acetic acid.f Mulder gives the formula of CisH 25^03 to sericin, and the following composition: Per Cent. Carbon 42.60 Hydrogen 5-9 Oxygen 35 . oo Nitrogen 16.50 According to Bolley, the composition of sericin is Per Cent. Carbon 44-32 Hydrogen 6. 18 Oxygen 31 . 20 Nitrogen 18 . 30 * Pure sericin may also be prepared by precipitating crude sericin solution with i per cent, acetic acid, washing the separated sericin by repeated decanta- tion with water, then treating with cold and afterwards with boiling alcohol, and finally extracting with ether. Pure sericin contains Carbon 45 . oo per cent. Hydrogen 6.32 " " Nitrogen 17.14" " Oxygen 31.54 " " It is easily soluble in water, in concentrated hydrochloric acid, and in potas- sium carbonate; sodium carbonate only causes a swelling. f By treatment with formaldehyde, it is claimed that sericin is rendered in- soluble in both hot water and soap solutions; consequently, raw silk may be treated with this reagent for use in certain applications where it may be desired to retain as far as possible the coating of silk-glue. CHEMICAL NATURE AND PROPERTIES OF SILK. 123 According to the tables of Cohnheim, the percentages of known constituents in silk-glue are as follows: Per Cent. Glycocoll /. . . . o. 1-0.2 Alanin 5 Leucin Not determined Serin 6.6 Tyrosin 5 Lysin Not determined Arginin 4 Ammonia 1.87 Vignon,* by observing the action of solutions of sericin and fibroin on polarized light, found that both of these constituents of silk were laevogyrate, and their rotatory powers were about equal, approximating to 40. This is in keeping with observa- tions made on other albuminoids. According to Dubois,f the yellow coloring-matter of silk is similar to carotin. He obtained five different bodies from the natural coloring-matter of silk, as follows: (i) a golden-yellow coloring-matter, soluble in potassium carbonate and precipitated by acetic acid; (2) crystals which appear yellowish-red by trans- mitted light and brown by reflected light; (3) a lemon-colored amorphous body, the alcoholic solution of which on evaporation gave granular masses; (4) yellow octahedral crystals resembling sulphur; (5) a dark bluish -green pigment in minute quantities and probably crystalline. 2. Chemical Reactions. In its general chemical behavior silk is quite similar to wool. It will stand a higher temperature, however, than the latter fibre, without receiving injury; it can be heated, for instance, to 110 C. without danger of decomposi- tion; at 170 C., however, it is rapidly disintegrated. On burning it liberates an empyreumatic odor which is not as disagreeable as that obtained from burning wool. Silk readily absorbs dilute acids from solutions, and in so doing increases in lustre and acquires the scroop of which mention has already been made. Unlike wool, it has a strong affinity for tannic acid, which fact is utilized for both weighting and mordanting the fibre. Silk * Compt. rend., vol. 103, p. 802. f Ibid. t vol. in, p. 482. 124 THE TEXTILE FIBRES. also absorbs sugar to a considerable degree, and this substance may be employed as a weighting material for light-colored silks on this account. Towards the ordinary metallic salts used as mordants silk exhibits quite an affinity; in fact, to such an extent can it absorb and fix certain metallic salts that silk material is frequently heavily mordanted with such salts for the purpose of unscrupulously increasing its weight. Solutions of sodium chloride appear to have a peculiar action on the silk fibre, especially in the presence of weighting materials. According to the researches of Sisley, solutions of common salt acting on weighted silk in the presence of air and moisture cause a complete destruction of the fibre in twelve months, if charged with but 0.5 per cent, of salt; i per cent, of salt causes a very pronounced tendering of the fibre in two months, while 2 to 5 per cent, of salt causes a distinct tendering in seven days. The action of the salt is shared in a lesser degree by the chlorides of potassium, ammonium, magnesium, calcium, barium, aluminium, and zinc, and is probably due to chemical dissociation. This fact may account for the stains sometimes found in skeins of silk which also show a tendering of the fibre. These stains have frequently been noticed, and thorough investigation has failed to satisfactorily account for them. The salt may get into the fibre through the perspiration of the workmen handling the goods, or through a variety of other causes. Silk is not as sensitive to dilute alkalies as wool, though the lustre of the fibre is somewhat diminished.* When treated with strong" hot caustic alkalies the silk fibre dissolves. Ammonia and soaps have no effect on silk beyond dissolving the silk-glue or sericin; though on long-continued boiling in soap, the fibroin is also attacked. Borax has no injurious action on silk, but neither has it any special solvent action on silk-glue, hence it is not serviceable as a stripping agent. If raw silk is steeped in lime- water, the fibre will swell to some extent and the silk-glue will become somewhat softened. If the action of the lime-water is continued, however, the silk will become brittle. Concentrated * It is said that when mixed with glucose or glycerin caustic soda does not dissolve the silk fibre to any extent, but only removes the gum. CHEMICAL NATURE AND PROPERTIES OF SILK. 125 sulphuric * and hydrochloric acids | dissolve silk; nitric acid % colors silk yellow, as in the case with wool, probably due to the formation of xanthoproteic acid. This color can be removed by treatment with a boiling solution of stannous chloride. The solubility of silk in strong hydrochloric acid is very rapid, a minute or two sufficing for complete solution. Under such con- ditions wool and cotton fibres are but slightly affected, so such a treatment may be used for the separation of silk from wool or cotton for the purpose of analysis. A concentrated solution of basic zinc chloride readily dissolves the silk fibre. || An * Though silk is soluble in concentrated acids if their action is continued for any length of time, it appears that if silk be treated with concentrated sul- phuric acid for only a few minutes, then rinsed and neutralized, the fibre will contract from 30 to 50 per cent, in length without otherwise suffering serious injury beyond a considerable loss in lustre. This action of concentrated acids on silk has been utilized for the craping of silk fabrics, the acid being allowed to act only on certain parts of the material. It appears that tussah silk is not affected by the acid to the same degree as ordinary silk, and hence craping may be accomplished by mixing tussah with ordinary silk, and treating the entire fabric with concentrated acid. f According to Farrell (Jour. Soc. Dyers 1 & Col., 1905, p. 70), when silk is treated with hydrochloric acid of a density of 29 Tw. it shrinks about one- third without any appreciable deterioration in the strength of the fibre. With solutions of acid below 29 Tw. no contraction occurs, while with solutions above 30 Tw. complete disintegration of the fibre results. In the production of crepon effects by this method, the fabric is printed with a wax resist, and is then immersed in the hydrochloric acid; the contraction is complete in one to two minutes, after which the fabric is well washed in water. Nitric acid and ortho-phosphoric acid may also be employed for the craping of silk fabrics (see C. and P. Depoully, Jour. Soc. Dyers' & Col., 1896, p. 8). According to a French patent, a similar effect may be obtained by treating silk with a solution of zinc chloride of from 32 to 76 Tw. (see Jour. Soc. Dyers' & Col., 1899, p. 214). J Vignon and Sisley (Compt. rend., 1891) found that the purified fibroin of silk when treated with nitrous nitric acid increased 2 per cent, in weight. The action of nitric acid on silk is rather a peculiar one. When treated for one minute with nitric acid of sp. gr. 1.33 at a temperature of 45 3 C., the silk acquires a yellow color which cannot be washed out and is also fast to light. Pure nitric acid free from nitrous compounds, however, does not give this color. On treating the yellow nitro-silk with an alkali, the color is considerably deepened. With strong sulphuric acid nitro-silk swells up and gives a gelatinous mass resembling egg albumin. || On diluting this solution with water a flocculent precipitate is obtained which is soluble in ammonia, and the latter solution has been employed for coat- ing vegetable fibres with silk for the production of certain so-called "artificial silks." 126 THE TEXTILE FIBRES. acid solution of zinc chloride acts in the same manner. Solutions of copper oxide or nickel oxide in ammonia also act as solvents towards silk. The latter solution can be em- ployed for separating silk from cotton, the silk being readily and completely soluble in a boiling solution of ammoniacal nickel oxide, whereas cotton loses less than i per cent, of its weight. A boiling solution of basic zinc chloride (1:1) will dissolve silk in one minute, while cotton under the same treatment loses only 0.5 per cent., and wool only 1.5 to 2 per cent.* Chlorin destroys silk, as do other oxidizing agents,- unless employed in very dilute solutions and with great care. Strong solutions of stannic chloride (70 Tw.) will dissolve silk, an action which should be borne in mind when mordanting and weighting silk with this salt. Hydrofluosilicic acid and hydrofluoric acid in the cold and in 5 per cent, solutions do not appear to exert any injurious action on the silk fibre; these acids, however, remove all inorganic weighting materials, and their use has been suggested for the restoring of excessively weighted silks to their normal condition, so that they may be less harsh and brittle. Towards coloring-matters in general, silk exhibits a greater capacity of absorption than perhaps any other fibre. It also absorbs dyestuffs at much lower temperatures than does wool. As silk is evidently an amido-acid, it possesses distinct chemical characteristics; that is to say, it exhibits both acid and basic properties in a manner similar to wool. Like the latter fibre (see page 50), it is probable that the active chemical groups in silk have considerable influence on its dyeing properties, es- pecially with reference to acid and basic dyes, for it has been shown f that if these active molecular groups are rendered inactive by acetylation or otherwise, the dyeing properties of the silk are accordingly altered. * Silk is also soluble in Schweitzer's reagent (ammoniacal copper oxide), and in an alkaline solution of copper sulphate and glycerin. The latter is used to separate silk from wool and cotton; and the following solution is recommended: 1 6 grams copper sulphate, 10 grams glycerin, and 150 c.c. of water. After dis- solving, add a solution of caustic soda, until the precipitate which at first forms is just redissolved. t Suida, Farber-Zeit., 1905. CHE MICA L NATURE AND PROPERTIES OF SILK. 127 3. Tussah Silk presents a number of differences, both physi- cal and chemical, from ordinary silk. It has a brown color and is considerably stiffer and coarser. It is less reactive, in general, towards chemical reagents, and consequently presents more difficulty in bleaching and dyeing. Tussah silk requires a much more severe treatment for degumming than cultivated silk, and the boiled-off liquor so obtained is of no value in dyeing. According to analyses of Bastow and Appleyard,* raw tus- sah silk gives the following results: Per Cent. Soluble in hot water 21 . 33 Dissolved by alcohol (fatty acid) 0.91 Dissolved by ether o . 08 Total loss on boiling off with i per cent, solution of soap 26.49 Mineral matter 5-34 These same observers consider that the fibroin of tussah silk differs chemically from that of ordinary silk, as it is not so readily acted on by solvents. In order to obtain pure tussah fibroin, the silk should be boiled repeatedly with a i per cent, solution of soap, washed with water, extracted with hydrochloric acid; and after again washing with water and drying, extracted successively with alcohol and ether. Tussah fibroin purified in this manner shows the following composition: Per Cent. Carbon 47 . 18 Hydrogen 6 . 30 Nitrogen 16 . 85 Oxygen 29 . 67 These figures are exclusive of 0.226 per cent, of ash. Apple yard gives the following analysis of the ash from raw tussah silk . Per Cent. Soda, Na 2 12 .45 Potash, K 2 31.68 Alumina, A1 2 O 3 i . 46 Lime, CaO ,. 13 . 32 Magnesia, MgO 2.56 Phosphoric acid, P 2 O 5 6.90 Carbonic acid, CO 2 n . 14 Silica, SiO: 9 . 79 Hydrochloric acid, Cl 2 .89 Sulphuric acid, SO 3 8.16 * Jour. Soc. Dyers' &> Col., vol. 4, p. 88. 128 THE TEXTILE FIBRES. The presence of sulphates in this ash is somewhat remark- able, as this constituent does not occur in ordinary silk. The occurrence of alumina is also remarkable, as this element is sel- dom a constituent of animal tissues. As the amount of ash of purified fibroin of both common silk and tussah silk is very much lower than that of the raw silks, it is to be considered prob- able that most of the mineral matter found is derived from adher- ing impurities, and is not a true constituent of the silk itself. Tussah silk is scarcely affected by an alkaline solution of copper hydrate in glycerin, whereas ordinary silk is readily soluble in this reagent.* The following table exhibits the principal differences between true silk and tussah silk: f Reagent. Mulberry Silk. Tussah Silk. Hot caustic soda (10%) Cold hydrochloric acid (sp. gr. 1.16) Cold cone, nitric acid Neutral solution of zinc chlo- ride (sp. gr. 1.725) Strong chromic acid solution in water Dissolves in 12 minutes Dissolves very rapidly Dissolves in 5 minutes Dissolves very rapidly Dissolves very rapidly Requires 50 minutes for solution Only partially dissolves in 48 hours Dissolves in 10 minutes Dissolves but slowly Dissolves very slowly While the fibre of mulberry silk presents the appearance of a structureless thread, and rarely exhibits signs of distinct striation, tussah (and other " wild " silks) is made up of bundles of delicate fibrillae, varying in diameter from 0.0003 to 0.0015 mm., so that the fibre as a whole presents a striated appearance. Also the cross-section % of tussah silk is considerably larger than that of mulberry silk, and is more flattened ; it also exhibits numerous fine air- tubes. The following table exhibits the difference in the microscopic appearance of various kinds of raw silk; the diameter is expressed in // = thousandths of a millimetre: * Filsinger, Chem. Zeit., vol. 20, p. 324. f Bastow and Appleyard, Jour. Soc. Dyers' & Col., vol. 4, p. 89. J Filsinger, vide supra. Hohnel, Jour. Soc. Chem. Ind., vol. 2, p. 172. CHEMICAL NATURE AND PROPERTIES OF SILK. 129 Variety of Silk. Diameter, n- Appearance. Broad Side. Narrow Side. True silk, Bombyx 20 tO 25 White or yellowish ; White or yellowish ; mori shiny shiny Senegal silk, B. 3 to 35 Shining yellowish or Gray, brown, or black, jaidherbi brownish white, or with occasionally pale yellow, gray, lighter shades brown, and occasion- ally bluish white Ailanthus si\k,Atta- 40 to 50 Shining yellowish white, Dirty gray or brown to cus cynthia with yellow, brown, or black, with green, yel- brownish-gray spots low, red, violet, or blue spots Yama-mai silk, 40 to 50 Bluish white with dark Glaring and fine colors, Anther aa yama- blue, blue and black with dark or black mai shades shades Tussah silk, Atta- 5 to 55 Irregular in thickness. Dark gray, with pink or cus selene Thickest parts with light green spots gray and blue spots; thinner parts bluish white, yellow, or orange-red Tussah silk, An- 60 to 65 Similar to above, but Similar to above ther&a mylitta spots orange-red, red. or brown The cocoon-threads of wild silks possess greater elasticity and tensile strength, as would naturally be expected from their greater thickness. The following table gives the elasticity and breaking strain of the principal varieties of silk : Variety of Silk. Elasticity, Per Cent. Breaking Strain , Grams. \Iulberry (Bombyx niori) . . .... 12 -z 4. 5 Tussah ( Anther (Bd ntylitta) . . . 10 I 12.8 Eria (Attacus ritini) IS .O 4.0 Muga (Anthcr&a assanicL) 21 . 7 6.7 Atlas (Attacus alias} IQ. I 5.6 Ailantnus (Attacus cynthia) 22 . <; 4.9 25.0 12.8 20.0 5.6 ^nthefCBa pwnyi 10 I 8.1 CHAPTER THE VEGETABLE FIBRES. i. General Considerations. The basis of all vegetable fibres is to be found in cellulose,* a compound belonging to a class of naturally occurring substances known as carbohydrates. The fibres may be seed-hairs, such as the different varieties of cotton, cotton-silk, etc.;f or bast fibres, which include those obtained from the cambium layer of the dicotyledonous plants, such as flax, hemp, jute, ramie, etc.; or vascular fibres, J which include those obtained chiefly from the leaf -tissues of the monocotyledo- nous plants, such as phormium, agave, aloe, etc. Anatomically considered, the plant fibres may be divided into six different classes (Hohnel): (1) Single-cell plant-hairs, such as cotton, vegetable silk, and vegetable down. (2) Fibres consisting of several cells, such as pulu fibre, elephant-grass, and cotton-grass. (3) Bast fibres, such as flax, hemp, jute, ramie, etc. (4) Dicotyledonous bast fibres, such as linden bast, Cuba bast, etc. * It is seldom, however, that cellulose actually occurs in the plant in the free condition, but is usually associated or chemically combined with other substances, of which the principal are fatty and waxy matters, coloring-matters, and tannins, and a rather indefinite group of so-called pectin matters, which appear to be more or less oxidized or acid derivatives of the carbohydrates. f In a certain sense, the cocoanut fibre (coir) may be included under the class of seed-hairs. J In China there is an example of a spinning fibre composed of the leaf-hairs of a plant. The latter apparently belongs to the Xeranthemum, and its leaves are covered with a thick mass of long hairy fibres, which are easily separated from the leaf when dried (see Wiesner, Die Rohstoffe des Pflanzenreiches, p. 167). There is a peculiar instance in which the entire plant is used as the fibre; this is sea-grass or sea- wrack (Zoster a marina). However, it can scarcely be considered as a textile fibre, as it is almost altogether employed for stuffing and packing. 130 THE VEGETABLE FIBRES. 13 r (5) Monocotyledonous vascular fibres, such as sisal hemp, aloe hemp, pineapple fibre, cocoanut fibre, etc. (6) Monocotyledonous sclerenchymous fibres, such as Manila hemp, New Zealand flax, etc.* There is considerable difference to be observed between the anatomical structure of seed-hairs and that of bast fibres. Seed- hairs are known botanically as plumose fibres, and usually consist of a unicellular fibre or trichrome, exhibiting only a single solid apex, the other end being attached to the seed. Externally they appear to be covered with a thin skin or cuticle which differs essentially from the remaining cellulose in that it is not dissolved by treatment with sulphuric acid. The cell-walls vary con- siderably in their thickness, and are structureless and porous. Through the centre of the fibre runs a hollow canal called the lumen. Usually the dried fibre is flattened into the form of a band, so that in cross-section the lumen appears as a line. Bast fibres, on the other hand, consist of completely enclosed tubes, each end being pointed. Each individual fibre is multicellular, the cells being long and usually polygonal in cross-section. f The cell-walls are usually rather thick, and the cross-section instead of being flat and narrow is broad and more or less rounded. The inner wall is frequently covered with a thin layer of dried protoplasm. One of the most characteristic appearances of the bast fibres is the occurrence of dislocations or joints through- * Zipser (Textile Raw Materials, p. 8 et seq.) gives the following classification for vegetable fibres: 1. Seed fibres, growing from the seeds or seed-capsules of certain plants, and including cotton, Bombax, Asckpias, etc. 2. Stem fibres, growing in the bast of certain dicotyledonous plants, and includ- ing flax, hemp, jute, etc. 3. Leaf fibres, occurring in the leaves of a number of monocotyledonous plants, and including New Zealand hemp, Manila hemp, aloe, etc. 4. Fruit fibres, of which the sole member worth mentioning is the cocoa- nut fibre. f The bast or vascular bundles consist of two parts, the phloem and the xylem. As a rule, the phloem occurs nearer the outside of the plant, while the xylem forms the principal structural part of the inside portion of the plant. The fibres in the phloem are usually rather easily detached and form the commercial product,, while those occurring in the xylem, as a rule, cannot be readily separated by mechanical means from the woody tissue in which they are imbedded. I 3 2 THE TEXTILE FIBRES. out the length of the fibre (see Fig. 42). These dislocations also show the property of becoming more deeply colored than the rest of the fibre when treated with a solution of chlor-iodide of zinc. These knots or joints generally show thicker overlying transverse fissures, between which lie small short discs arranged on edge. The joints disappear altogether in the monocotyledonous fibres; they are also lacking on many true bast fibres, such as jute, linden bast, etc., but occur in hemp, flax, ramie, etc. FIG. 42. FIG. 43. FIG. 42. A Typical Bast Fibre (X35o) showing the Jointed Structure or Dis- locations at D. (Micrograph by author.) FIG. 43. A Bundle of Bast Fibres. (X4OO.) (After Lecomte.) Bast fibres are the long, tough cells found in the barks and stems of various plants. The cell- walls of these fibres are usually partially changed from pure cellulose into lignin and are thickened. There is usually a considerable amount of foreign matter also contained in the cell- wall, and often this becomes sufficiently characteristic to serve as a means of identifying the various fibres by the application of chemical reagents. Fibres which contain only pure cellulose are colored blue when treated with THE VEGETABLE FIBRES. 133 the iod in-sulphuric acid reagent (see chapter xvii), while fibres containing lignin are colored yellow to brown with the same test. Unlike seed-hairs, the individual cells of bast fibres are not of sufficient length for use in spinning, but as they are held together with considerable firmness to form bundles of great length, they are utilized in this form. Wiesner gives the following table showing the length of the raw fibre and the dimensions of the cells composing them. Fibre. Length of Raw Fibre, cm. Length of Cells, mm. Breadth of Cells. Min. ft. Max. fi. Aver. ft. 15 J 3 16 16 16 15 16 20 20 5 25.2 25-9 I8. 5 29.4 29.9 38 15 20 12 21 20 17 16 Tillandsia fibre 2-22 10-40 50-90 80-IIO 60-70 50-150 150-300 IOO-l8o IOO-I20 80-IOO 20-30 40-50 20-140 100-300 150-300 40-90 2O-50 IOO-IIO 4.05 3-5 1 1.82 2.84 2.50 2-3 2-3 0.2-0.5 1.5-1.9 o. 1-1.6 2-5-5-6 o. i 1.6 1.5-4.0 o . 8-4 . i 0.9-4.7 1.1-3.2 0.8-2.3 0.7-3.0 1-3-3-7 2 . 0-4 . O o . 8-4 . i o . 8-4 . i 4.0-12.0 0.5-6.9 1.4-6.7 22. O 8.0 40.5 35 - 1 18.2 28.4 25.0 20-30 20-30 10-30 10-25 10-56 3-45 I . 1-2 . 6 i-S-3-5 0.9-2. i 1-2 0.4-5.1 4 I . 0-4 . 2 I . 0-2 . 2 o . 4-0 . 9 6 9 14.7 8 8 8 10 12 9 15 15 12 16 16 20 20 27 40 l6 I 9 .2 !7 11.9 20. I 20 19 12 20 19 49 33 i7 9 I? 8 16 12 15 15 16.8 29 20 20 21 21 24 25 25 24 2 5 32 32 41 42 42 80 12.6 27.9 27.1 22 29.9 37-8 29 42 44 33 92 5 25 14 24 2 9 21 20 Ksparto grass. Phormiutn tenax Abclmochus tctraphyllos Bduhinid Tdccmosd lute (Corchorus c&psul&ris) Calotropis pigdntcd (bast) Aloe pcrjolidtd Flax (Linum usitdtissitnuni) Hemp (Cdnndbis sdtivo) lute (CoTchofus olitorius) Hibiscus cdnndbinus Sunn (Cfotoldfia iunccd) Brotnclid kdTdtdS China grass (Bohmerid nivea) Ramie (Bdhmeria tenacissima) Cotton (Gossypium barbadense) do (G conglotnerdtuni) do (G herbdceunt) do (G dcumindtuni) do (G. arboreurri) Cotton wool (Bombdx heptaphyllum] . Vegetable silk (Calotropis gigantea). . (Jo (Asclcpids) do (Strophdnthus) do (BedUttiontid) Linden-bast Sterculid villosd Holoptclid integriiolid Kydid cdlycind Ldsiosyphon speciosus Sponid wi&htii , Pdtiddnus odofdtissimus Pita fibre Coir fibre 134 THE TEXTILE FIBRES. Vtillard gives a somewhat similar table as follows: Name. Length (in mm.). Breadth (in //). Mm. Max. Mean. Min. Max. Mean. Linen 4 5 4 4 60 4 2 5 5 10 2 I .2 i-5 3 66 55 J 9 57 2 5 2 5 12 9 16 18 40 6 5 I 3 3-5 4-5 9 10 2-5 'i 6 4 12 '6 5 3-5 3 3 i 2 5 20 IO 27 120 10 8 5 10 10 5 2 2 5 2 J -5 2-5 5 5 2 9 4 3 2-5 6 5 3 3 2-5 2-5 J -5 0.7 3 12 20 37 5 26 70 80 20 22 16 5 5 30 3 J 5 20 3 21 16 22.5 22 12 15 6 24 ;i 15 20 24 24 28 20 24 II 16 12 20 Hemp (Cannabis saliva) Hop fibre (Humulus lupulus) Nettle fibre (Urtica dioici) Ramie ( Urtica nivea) Fibre of paper mulberry Sunn hemp (Crotalaria juncea) Broom-grass (Sarothamnus vulgario) Feather-grass (Spartium junceum}. . Meliotus alba 2 5 10 20 14 14 20 10 17 7 12 4 20 8 10 10 15 20 16 20 16 16 10 12 IO 12 5 2 5 ' 36 ' 33 20 2 5 20 3 18 20 8 32 16 20 20 26 3 2 32 40 24 28 13 20 16 24 Cotton Gam bo hemp (Hibiscus cannabinus} Linden-bast (Tilia europcsa). . . Jute (Corchorus capsularis) Lagetta lintearia Salix alba Esparto -5 J -3 3 2 .5 0.8 5 -5 5 5 5 5 5 0.4 LygcKUnt spartum Pineapple fibre Brotnelia karatas. Bromelia pinguin New Zealand flax (Phormium tenax). Yucca fibre Sanseveria fibre Pita (Agave americana) . . . Manila hemp (Musa textilis). . . . Musa paradisaica Phoenix dactylifera Corypha umbraculijera Elais guineensis RapHia, taetigera . . Mauritia flexuosa. . .... Coir fibre (Cocas nucifera) 1200 1000 620 55 2400 35 260 330 500 330 240 I2 5 90 500 90 830 210 15 550 170 ISO IOO 250 180 150 I2O 230 1 60 I 3 35 2. Classification. Perhaps the most systematic and complete enumeration of the various vegetable fibres, together with a classification of their technical uses, is that given by Dodge,* from which the following abstract is taken. STRUCTURAL CLASSIFICATION. A. FlBRO VASCULAR STRUCTURE. i. Bast fibres. Derived from the inner fibrous bark of dicot- yledonous , plants or exogens, or outside growers. They are * Report on .Useful Plant Fibres of the World. THE VEGETABLE FIBRES. 135 composed of bast-cells, the ends of which overlap each other, so as to form in mass a filament. They occupy the phloem portion of the fibro vascular bundles, and their utility in nature is to give strength and flexibility to the tissue. , 2. Woody fibres. (a) The stems and twigs of exogenous plants, simply stripped of their bark and used entire, or separated into withes for weaving or plaiting into basketry. (b) The entire or subdivided roots of exogenous plants, to be employed for the same purpose, or as tie material, or as very coarse thread for stitching or binding. (c) The wood of exogenous trees easily divisible into layers or splints for the same purposes, or more finely divided into thread-like shavings for packing material. (d) The wood of certain soft species of exogenous trees, after grinding and converting by chemical means into wood- pulp, which is simple cellulose, and similar woods more carefully prepared for the manufacture of artificial silk. 3. Structural fibres. (a) Derived from the structural system of the stalks, leaf- stems, and leaves, or other parts of monocotyledonous plants, or inside growers, occurring as isolated fibrovascular bundles, and surrounded by a pithy, spongy, corky, or often a soft, succu- lent, cellular mass covered with a thick epidermis. They give to the plant rigidity and toughness, thus enabling it to resist injury from the elements, and they also serve as water-vessels. (b) The whole stems, or roots, or leaves, or split and shredded leaves of monocotyledonous plants. (c) The fibrous portion of the leaves or fruits of certain exogenous plants when deprived of their epidermis and soft cellular tissue. B. SIMPLE CELLULAR STRUCTURE. 4. Surface fibres. (a) The down or hairs surrounding the seeds, or seed en- velopes, or exogenous plants, which are usually contained in a husk, pod, or capsule. I3 6 THE TEXTILE FIBRES. (b) Hair-like growths, or tomentum, found on the surfaces of stems and leaves, or on the leaf -buds of both divisions of plants. (c) The fibrous material produced in the form of epidermal strips from the leaves of certain endogenous species, as the palms. 5. Pseudo- fibres, or false fibrous material. (a) Certain of the mosses, as the species of the Sphagnum, for packing material. (b) Certain leaves and marine weeds, the dried substance of which forms a more delicate packing material. (c) Seaweeds wrought into lines and cordage. (d) Fungus growths, or the mycelium of certain fungi that may be applied to economic uses, for which some of the true fibres are employed. The bast fibres * are clearly defined, and all such fibres when simply stripped are similar in form as to outward appearance, differing chiefly in color, fineness, and strength. An example of a fine bast fibre is the ribbons or filaments of hemp. The woody fibres f are only fibrous in the broad sense, as their cellulose is broken down and all extraneous matter removed by chemical means, as for the manufacture of paper-pulp or of artificial silk. The structural fibres t are found in many forms differing widely * The bast fibres are derived from the bark of exogeneous plants, such as trees, shrubs, the climbing vines, and herbaceous vegetation generally. f The greater number of woody fibres are merely wood in the form of flexi- ble slender twigs or osiers that are useful for making baskets; or the larger branches may be split or subdivided into strips, withes, or flat ribbons of wood, for making coarser baskets. The softer woods still further divided give the product known as "excelsio"," which can only claim a place in the list of fibres on account of its use in upholstery or packing. J The structural fibres are to be found in many forms, among which may be enumerated the following: The stiff, white, or yellowish fibres forming the struc- ture of all fleshy -leaved or aloe-like plants, as the century plant, the yuccas, agave, and pineapple, or the fleshy trunk of the banana; the coarser bundles of stiff, fibro s substance which gives strength to the trunks, leaf, stem, and even the leaves of palms, such as piassave, derived from the dilated margins of the petioles of a palm; stiff fibres extracted by maceration from the bases of the leaf- stems of the cabtage palmetto, or the shredded leaves of the African fan palm, known as Crin vege'al; rattan strips and fibrous material derived from bamboo, the corn-stalk, broom-corn, and from reeds, sedges, and grasses; still other forms are the coir fibre surrounding the fruit of the cocoanut, the fibre from pine-needles, THE VEGETABLE FIBRES. 137 from each other, and the surface fibres * are still more varied in form. ECONOMIC CLASSIFICATION.! A. SPINNING FIBRES. 1. Fabric fibres. (a) Fibres of the first rank for spinning and weaving into fine and coarse textures for wearing apparel, domestic use, or house-furnishing and decoration, and .for awnings, sails, etc. (The commercial forms are cotton, flax, ramie, hemp, pineapple, and New Zealand flax.) (b) Fibres of the second rank, used for burlap or gunny, cotton bagging, woven mattings, floor-coverings, and other coarse uses. (Commercial examples are coir and jute.) 2. Netting fibres. (a) Lace fibres, which are cotton, flax, ramie, agave, etc. (b) Coarse netting fibres, for all forms of nets, and for hammocks. (Commercial forms: Cotton, flax, ramie, New Zealand flax, agave, etc.) 3. Cordage fibres. (a) Fine-spun threads and yarns other than for weaving; cords, lines, and twines. (All of the commercial fabric fibres, and the fibrous mass filling the sponge cucumber, which is a peculiar example of a structural fibre derived from an exogenous plant. * Surface fibres may consist of the elongated hairs surrounding the pods of the thistle, and known as thistle-down, or they may be fibrous growths around seed clusters, as the cotton -boll, the milk-weed pod, etc., or they may be the leaf scales or tomentum found on the under surface of leaves or epidermal strips of palm leaves, such as raffia. f Dewey (Year-Book, Dept. Agric. 1903) gives the following economic classi- fication of the vegetable fibres: (1) The cottons, with soft, lint-like fibre inch to 2 inches long, composed of single cells, borne on the seeds of different species of cotton-plants. (2) The soft fibres, or bast fibres, including flax, hemp, and jute; flexible fibres of soft texture, 10 to 100 inches in length, composed of many overlapping cells and contained in the inner bark of the plants. (3) The hard, or leaf, fibres, including Manila, sisal, Mauritius, New Zealand fibres, and istle, all having rather stiff, woody fibres i to 10 feet long, composed of numerous cells in bundles, borne in the tissues of the leaf or leaf-stem. 138 THE TEXTILE FIBRES. sunn, Mauritius, and bowstring hemps, New Zealand flax, coir, Manila, sisal hemps; the fish-lines made from seaweeds.) (b) Ropes and cables. (Chiefly common hemp, sisal, and Manila hemps, when produced commercially.) B. TIE MATERIAL (rough twisted). Very coarse material, such as stripped palm-leaves, the peeled bark of trees, and other coarse growths used without preparation. C. NATURAL TEXTURES. 1 . Tree-basts, with tough interlacing fibres. (a) Substitutes for cloth, prepared by simple stripping and pounding. (b) Lace-barks,* used for cravats, frills, ruffles, etc., and for whips and thongs. 2. The ribbon or layer basts, extracted in thin, smooth-sur- faced, flexible strips or sheets. (Cuba bast f used as millinery material, cigarette wrappers, etc.) 3. Interlacing structural fibre or sheaths. (a) Pertaining to leaves and leaf-stems of palms, such as the fibrous sheaths found at the bases of the leaf-stalks of the cocoanut. (b) Pertaining to flower-buds. The natural caps or hats derived from several- species of palms. D. BRUSH FIBRES. i . Brushes manufactured from prepared fibre. (a) For soft brushes. (Substitutes for animal bristles, such as Tampico.) * The lace-bark tree is the Lagetta lintearia, and grows principally in Jamaica. The fibre (or rather fabric) is obtained from the inner bark, occurring in con- centric layers which are easily detachable, and which are suited to the most deli- cate textiles; when stretched out they form a pentagonal or hexagonal mesh very closely resembling lace. f The Cuba bast here referred to is the lace-like inner bark from the Hibis- cus elatus, which was formerly largely used for tying up bundles of Havana cigars. The plant also yields a bast fibre which is coarse but very strong, and is suitable for the making of cordage and coffee bags. THE VEGETABLE FIBRES. 139 (b) For hard brushes. (Examples: Palmetto fibre, pal- myra, kittul,* etc.) 2. Brooms and whisks. (a) Grass-like fibres. (Examples: Broom- root, broom- corn, etc.) (b) Bass fibres. (Monkey bass, etc.) 3. Very coarse brushes and brooms. Material used in street-cleaning. Usually twigs and splints. E, PLAITING AND ROUGH-WEAVING FIBRES. 1. Used in hats, sandals, etc. (a) Straw plaits. From wheat, rye, barley, and rice straw. (Tuscan and Japanese braids.) (b) Plaits from split leaves, chiefly palms and allied forms of vegetation. (Panama hats.) (c) Plaits from various materials. (Bast and thin woods used in millinery trimmings.) 2. Mats and mattings; also thatch materials. (a) Commercial mattings from Eastern countries. (b) Sleeping- mats, screens, etc. (c) Thatch- roofs, made from tree-basts, palm-leaves, grasses, etc. 3. Basketry. (a) Manufactures from woody fibre. (b) From whole or split leaves or stems. 4. Miscellaneous manufactures. Willow- ware in various forms; chair-bottoms, etc., from splints or rushes. F. VARIOUS FORMS OF FILLING. T. Stuffing or Upholstery. (a) Wadding, batting, etc., usually commercially pre- pared lint-cotton. * Kittul, or kittool, fibre is obtained from the jaggery palm, Caryota urens. The structural fibre is brownish black in color and lustrous, the filaments being straight and smooth. It somewhat resembles horse-hair and curls like coir when drawn between the thumb and nail of the forefinger. In Ceylon the fibre is used for the manufacture of ropes of great strength which are used for tying elephants. It is largely used for making brushes of various kinds, especially machine brushes for polishing linen and cotton yarns, and for brushing velvets. '140 THE TEXTILE FIBRES. (b) Feather substitutes for filling cushions, etc.; cotton f seed-hairs, tomentum from surfaces of leaves, other soft fibrous material. (c) Mattress and furniture filling; the tow or waste of prepared fibre; unprepared bast, straw, and grasses; Spanish moss, etc. 2. Caulking. (a) Filling the seams in vessels, etc.; oakum from various fibres. (b) Filling the seams in casks, etc.; leaves of reeds and giant grasses. 3. Stiffening. In the manufacture of " staff " for building purposes, and as substitutes for cow-hair in plaster; New Zealand flax; pal- metto fibre. 4. Packing. (a) In bulkheads, etc. Coir, cellulose of corn-pith. In machinery, as in valves of steam-engines; various soft fibres. (b) For protection in transportation; various fibres and soft grasses; marine weeds; excelsior. G. PAPER MATERIAL. 1. Textile papers. (a) The spinning fibres in the raw state; the secondary qualities or waste from spinning-mills, which may be used for paper- stock, including tow, jute-butts, Manila rope, etc. (b) Cotton or flax fibre that has already been spun and woven, but which, as rags, finds use as a paper material. 2. Bast papers. This includes Japanese papers from soft basts, such as the paper mulberry. 3. Pal in papers. From the fibrous material of palms and similar plants. Palmetto and yucca papers. 4. Bamboo and grass papers. This includes all paper material from gramineous plants, including the bamboos, esparto, etc. THE VEGETABLE FIBRES, 141 5. Wood-pulp, or cellulose. The wood of spruce, poplar, and similar " paper-pulp " woods prepared by various chemical and mechanical processes. Wiesner gives the following botanical classification of the more important vegetable fibres: A. VEGETABLE HAIRS. 1. Cotton (seed-hairs of Gossypium sp.). 2. Bombax cotton (fruit-hairs of Bombacece). 3. Vegetable silks (seed-hairs of various Asclepiadacece and Apocynacece). B. BAST FIBRES FROM THE STALKS AND STEMS OF DICOTYLE- DONOUS PLANTS. (a) Flax-like fibres. 4. Flax (Linum usitatissimum). 5. Hemp (Cannabis sativa). 6. Gambo hemp (Hibiscus cannabinus). 7. Sunn hemp (Crotalaria juncea). 8. Queensland hemp (Sida retusa). 9. Yercum fibre (Calotropis gigantea). (b) Bcehmeria fibres. 10. Ramie or China grass (Bcehmeria nivea). (c) Jute-like fibres. 11. Jute (Cor chorus capsularis and C. olitorius). 12. Raibhenda (Abelmochus tetraphyllos). 13. Pseudo-jute (Urena sinuata). (d) Coarse bast fibres. 14. Bast fibres from Bauhinia racemosa. 15. Bast fibres from Thespesia Lampas. 1 6. Bast fibres from Cordia lati folia. (e) Basts. 17. Linden bast (Tilia sp.). 1 8. Bast from Sterculia villosa. 19. Bast from Holoptelea integri folia. 20. Bast from Kydia calycina. 21. Bast from Lasiosyphon speciosus. 22. Bast from Sponia wightii. Or i nt UNIVERSITY ii OF /Jif t % 142 THE TEXTILE FIBRES. C. VASCULAR BUNDLES FROM MONOCOTYLEDONOUS PLANTS. (a) Leaf fibres. 23. Manila hemp (Musa textilis and others of this kind). 24. Pita (Agave americana and A. mexicana). 25. Sisal (Agave rigida). 26. Mauritius hemp (Agave jaetida). 27. New Zealand flax (Phormium tenax). 28. Aloe fibres (Aloe sp.). 29. Bromelia fibres (Bromelia sp.). 30. Pandanus fibres (Pandanus sp.). 31. Sansevieria fibres (Sansevieria sp.). 32. Sparto fibres (Siipa tenacissima}. 33. Piassave (Attalea junijera, Raphia vinijera, etc.). (b) Stem fibres. 34. Tillandsia fibres, southern moss (Tillandsia usne- oides). (c) Fruit fibres. 35. Coir or cocoanut fibre (Cocos nucifera). 36. Peat fibres. (d) Paper fibres. 37. Straw fibres (rye, wheat, oat, rice). 38. Esparto fibres (leaf fibres of Stipa tenacissima). 39. Bamboo fibres (Bambusa sp.). 40. Wood fibre (pine, fir, aspen, etc.). 41. Bast fibre from paper mulberry (Broussonetia papy- ri j era). 42. Bast fibre from Edgeworthia papyri jera. 43. Peat fibres. Lecomte (Textiles vegetaux) gives the following classification with reference to the botany of the textile fibres: A. VEGETABLE HAIRS. Cotton. Asclepias. . . \ Minor vegetable hair fibres. Epilooium. Typha, etc. THE yEGETABLE FIBRES. 143 B. BAST FIBRES. I. Dicotyledons. a. Urticacea family. Hemp (Cannabis). Ramie (Bxhmeria). Nettle (Urtiai). Paper mulberry (Broussonetia). Hop (Humulus). b. LinacecB family. Linen (Linum). c. Thymelcacece family. Lace bark (Lagelta). Nepal paper (Daphne). d. Tiliacecz family. Jute (Corchorus). Linden (Til la). e. Malvacccv family. Queensland hemp (Sida). Caesar weed (Urcna). Pseudo-hemps (Hibiscus). /. PapilionacecB family. Sunn hemp (Crotalaria). Clover (Melilotus). Ginestra (Genista). Spanish sparto (Spartium). g. Cordiacea family. Cordia fibres. h. Asclepiadacece family. Giant asclepias (Calotropis). II. Monocotyledons. a. Graminea family. Sparto grass (Stipa). Weeping sylvan (Lygeum) b. Liliacece family. New Zealand hemp (Phormium), Yucca (Yucca sp.). Bowstring hemps (Sansevieria). 144 THE TEXTILE FIBRES. c. Amaryllidacetz family. Sisal hemps (Agave). d. BromeliacecB family. Pineapple (Ananas). Bromelia fibres (Bromelia). e. Musacea family. Manila hemp (Musa). ). Naiadacece family. Sea wrack (Zoster a), g. Palmce family. Coir (Cocos). Raffia (Raphia). Murumuru palm (Astrocaryum). Crin vegetal (Chamcerops). Rattan cane (Calamus). Sago-palm (Arenga). Date-palm (Phoenix). Talipot palm (Corypha). Oil-palm (Eltsis). 3. Physical Structure and Properties. Seed-hairs, or plumose fibres, are divided into three morphological classes: (1) Those consisting of single cells, one end of which is closed and tapers to a point, the other end being broken off abruptly where it is torn from the seed to which it was fastened during growth. This class includes the most important plumose fibres, such as cotton and the vegetable silks. (2) Those consisting of a series of cells joined together to form a continuous fibre; this class includes the tomentum or epidermal hair obtained from certain ferns, and are practically valueless as textile materials, though used for upholstery and such purposes. (3) Those consisting of several series of cells, represented by the fibres of the so-called cotton-grass and elephant- grass. The hair fibres may originate on almost any organ of the plant exposed to the air. The following table indicates the origin of the majority of such fibres : * * See Lecoiiite, Textiles veg&aux. THE VEGETABLE FIBRES. 145 Hair Fibres. (1) Covering the seeds, either entirely or in part: Cotton Malvacece. Marsdenia Calotropis Asckpias \Asckpidece. Vincetoxicum j Beaumontia } . ., \Apocvne(B. Strophantus j Epilobium (Enoiheracea. (2) Contained in the flower (rudimentary floral envelope): Typha Typhacea. Eriophorum. .. .Cyperacea. (3) Lining the interior of the fruit: Ochroma ] Bombaoc \ Bombacece. Eriodendron. . J (4) Covering stalks and leaves: Cibotium Ferns. The cell- wall of the plumose fibres in some cases is relatively thin, while in others it is comparatively thick. It is generally without apparent structure, though sometimes it is seen to con- tain pores, and occasionally a mesh-like interlacing of filaments is observable, especially at the base of the fibre. The inner surface of the cell- wall is usually coated with a cuticle of dried protoplasm, which is evidently similar in constitution to the outer cuticle, as it also remains undissolved when the fibre is dissolved in either concentrated sulphuric acid or an ammo- niacal solution of copper oxide. Lecomte* gives the following classification of vegetable fibres with respect to their cellular structure : i. Fibres consisting of a single isolated cell: Hairs. Fibres. Cotton. Cottonized ramie and china-grass. Ascelpias silk Bombaoc cotton. * Textiles vegelaux. 146 THE TEXTILE FIBRES. 2. Single fibres associated in bundles: Unbleached jute. Linen (poorly prepared linen frequently contains paren- chym cells and epidermal cells). Ambari hemp (Hibiscus). Ramie. Hemp (well prepared). 3. Fibres with medullary cells: Queensland hemp (Sida retusa). Cordia latijolia. Thespesia lampas. 4. Fibres with parenchym cells: Abelmoschus tetraphyllos. Urena sinuata. Sunn hemp (Crotalaria juncea). Calotropis gigantea. Hemp (as often prepared). The general term of bast fibre includes really two distinct forms; if the fibre occurs in the bast itself it should be designated as true bast fibre, such as linen, hemp, and jute. When, however, the fibres do not occur in the bast, but in single bundles in the leaf structure of the plant, they should be designated as sclerenchymous fibres. In true bast fibres there are seldom to be noticed distinct pores, whereas the sclerenchymous fibres are abundantly supplied with them. On the other hand, however, the true bast fibres frequently show peculiar dislocations or joints caused by an unequal cell pressure in the growing plant; these are entirely absent in the sclerenchymous fibres. The ends of all bast fibres are usually quite characteristic and exhibit a wide diversity of forms; at times they are sharp-pointed and again blunt; some possess but a single point, while others are split or forked; some- times the cell-wall is thicker than in the rest of the fibre, and sometimes it is thinner. When the cells occur in bundles they are frequently separated from one another by a so-called median layer, which forms a sort of matrix in which the separate filaments are imbedded. This layer usually differs in its chemical com- position from the cell- wall proper, and gives different color THE VEGETABLE FIBRES. 147 reactions with various reagents, as it generally consists of lignified tissue. In many cases the cell-walls appear to have a distinct structure, being composed of concentric layers which in cross- section exhibit a stratified appearance. The bast fibres may be roughly divided into four classes with reference to the comparative sizes of the cell- wall and the inner canal or lumen: (1) The canal takes up about four-fifths of the diameter of the fibre: Ramie and china-grass. (2) The canal is about two-thirds of the diameter of the fibre: Pineapple fibre, Hemp, Pita and sunn hemp. (3) The canal is mostly less than one-half the diameter of the fibre: Ambari hemp (Hibiscus), Yucca, New Zealand hemp (Phormium tenax), Manila hemp. (4) The canal is often reduced to a mere line: Linen. TJie inner canal is very regular (and consequently the cell- wall will be of uniform thickness) in fibres of yucca, New Zealand hemp, sunn hemp, pita, hemp, linen, ramie, and the plumose fibres. On the other hand, the canal is irregular (with resulting irregularities in the thickness of the cell- wall) in fibres of jute, coir, Urena sinuata, Abelmoschus, etc. All plant-cell membranes are doubly refractive towards light, and this is especially true of thick- walled cells which are parallel to the fibre proper. If such a fibre is examined in the dark field of a micro-polariscope it shows a beautiful arrangement of bright prismatic colors. The degree of double refraction varies with different fibres; in some, as for example in coir, it is very weak, while in others, such as linen and hemp, it is very strong. The following table gives the polarization colors shown by various fibres: THE TEXTILE FIBRES. Fibre. Polarization Colors. Vascular and parenchy- ^ mous cells of wood > Dark gray, and straw ) Epidermal cells of straw ) , \ Dark gray, and esparto ) Coir Dark gray. ( Dark gray to light grav; also Cotton ) ,. .. I white to yellow. New Zealand flax Ditto. Fibre cells of jute and ( Dark gray to light gray; yel- esparto ( lowish to red. Bast cells of flax and ( mite ' y ellowish - oran S e ' red ' ^ e < violet, changing to yellowish ( white and violet. In color the vegetable fibres vary considerably in the raw state; some, like cotton, ramie, and the vegetable silks, are almost pure white. Others, like linen, possess a grayish-brown color; while others yet, like jute and hemp, have a decided brown color. These colors, however, are due to incrusting impurities, as the cellulose fibres, punned and freed from all such foreign matters, are always white/**" In lustre the vegetable fibres are usually below those of animal origin, and especially silk, though they differ much in this respect. Cotton probably has the least lustre of any, as its surface as by no means smooth and even, but presents a wrinkled and creased appearance, hence scatters the rays of light reflected therefrom. The other plumose fibres, as the various vegetable silks, have a very smooth surface, and consequently exhibit considerable lustre. Linen, jute, ramie, and the bast fibres in general, when separated into their fine filaments and properly freed from all incrusting matter, possess a rather high degree of lustre; for though they have more or less roughened places and irregularities on their surface, the major portion of such surface is smooth and regular. The more closely the fibre approximates to pure cellulose the greater becomes its flexibility and elasticity, and the more it is THE VEGETABLE FIBRES. 149 lignified * the less these qualities become. That is to say, the highly lignified fibres are stiff and brittle and but little adapted to the spinning of fine yarns. In tensile strength the vegetable fibres vary considerably; owing to the great difference in the physical form and thickness of the various fibres, it is difficult to give a comparison of their respective strengths. The following table gives a comparison between the more important fibres: Fibre. Cotton Breaking Length in Kilometres. . 27 O Tensile Strength, Kilograms per Sq. Millimetre. 34 27 Linen 24. O Tute 34 "? 4.Q ? I Hemp r 2 O 78 oo Coir 17 8 Manila hemp . 3i 8 Chins, crass 20 o Raw silk. . . ^0.8 AO.OA The hygroscopic moisture contained in vegetable fibres is considerably lower than that present in either wool or silk. While the latter fibres under normal atmospheric conditions will aver- age as much as 12 to 16 per cent, of moisture, cotton and linen will have only from 6 to 8 per cent. The table on page 150 (after Wiesner) gives the amount of moisture in various vege- table fibres in the ordinary air-dry condition, and also the greatest amount they will absorb hygroscopically. 4. Chemical Composition and Properties. Although cellulose forms the chief constituent of all vegetable fibres, it varies much in its purity and associated products in its occurrence in the various fibres. Seed-hairs, like cotton, consist almost entirely of cellulose in a rather pure state, but the bast and vascular fibres always contain more or less alteration products of cellulose, chief among which is ligno-cellulose, or lignin; in fact jute is almost entirely composed of this latter substance. Seed -hairs mostly consist of one single cell to the individual fibre and have very little foreign or incrusting material present. The other * The term lignified means that the fibre is more or less changed into woody tissue. THE TEXTILE FIBRES. HYGROSCOPIC MOISTURE IN VEGETABLE FIBRES. Fibre. Air-dry Condition. Maximum Amount Hygroscopic Cotton 6 66 Flax (Belgian) . , 5 70 ^w.yy Tute. . x^.yu China grass 6 C2 2 3-3 18 T c Manila hemp . . w-5* 10. 15 Sunn hemp 531 10 87 Hibiscus cannabinus J 1 7 ?8 Abclmoschus tetraphyllos / 6 6 80 Esparto. . Utsna sinuata u -So 7 O2 I 3- 3 2 Piassave * 16 98 Sida retusa 7d.Q 17 II A loe perfoliata 6 QC 18 o-? Bromelia karatas 6 82 18 10 Thespcsia lampas jo 8? 18 io Cordia latiiolia 8 o? l8 22 Bauhinia racemosa f -yo 7 84 Tillandsia fibre 900 Pita 12 3O 7Q OO CalotTopis gigantea (bast) C 67 u / J 3- J 3 fibres are made up of an aggregation of cells bound together in a compact form, and in the cell interstices there is always present more or less gummy and resinous matter, oils, mineral matter, and lignified tissue. All vegetable fibres appear to contain more or less pigment matter, usually of a slight yellowish or brownish color. In ordinary cotton and ramie this coloring- matter occurs in only a very small amount and the natural fibre is quite white in appearance. There are some varieties of cotton, however, which are distinctly brown in color. Flax, jute, hemp, * Piassave fibre is obtained from a palm-tree, Attalea junifera. It is a struc- tural fibre obtained from the dilated base of the leaf-stalks. It is stiff, wiry, and bright chocolate in color, and is principally used in the manufacture of brushes. It is also used on the street-sweeping machines in London. The palm grows principally in Brazil, where the natives use the fibre for making coarse cables, which are very durable and so light that they will flqat on the water. f The Bauhinia is a genus of arborescent or climbing plants found in tropical countries. The fibre is obtained from the bast of the inner bark, and may be made into coarse cordage, but it soon rots in water. The fibre is reddish in color and tough and strong, and has been employed in India for the construction of bridges. THE VEGETABLE FIBRES. 151 etc., contain a considerable amount of pigment and are of a more or less pronounced brownish color. Besides cellulose and lignin, there is also present, especially in seed-hairs, a cutose membrane (cork tissue) in the form of an external cuticle. Cutose is insoluble in concentrated (sulphuric acid, but is slightly soluble in boiling caustic potash. It doubt- less originates from the plant- wax which is imbedded in the cell. Albuminous matter also occurs in the fibre elements, mostly as a dried tissue which fills the lumen of the fibre more or less com- pletely. It also occurs as a thin film which coats 'the inner wall of the cell and remains undissolved when the fibre is treated with concentrated sulphuric acid. This membrane exhibits all the reactions of albumin. Silicic acid sometimes is present in vege- table fibres, but only in the walls of the stegmata and in epidermal cells. On ignition the silicious matter is left in almost the original form of the fibre. The silicious skeleton is insoluble in hydrochloric acid, whereas the rest of the ash is readily dissolved by this reagent. Crystals of calcium oxalate occasionally occur in some fibres; they are insoluble in acetic but dissolve in hydro- chloric acid. On ignition of the fibres these crystals are con- verted into calcium carbonate without much change of form, and then are soluble in even very dilute acids. Woody fibre is to be found in many vegetable fibres, and its presence always lowers the economic value of the fibre. The presence of woody fibre may readily be determined by the appli- cation of a number of characteristic chemical tests. Anilin sulphate, for instance, with woody fibre gives a golden yellow color; phloroglucol with hydrochloric acid gives a red color, phenol with hydrochloric acid a green color, as does also indol with hydro- chloric acid, and a solution of chlor-iodide of zinc gives a brownish yellow color. Woody fibre is also destroyed by the action of alkalies and hypochlorites in the bleaching process; and in fact this process usually has for its chief object the decomposition and removal of the woody fibre which may be present. Due to this fact, certain bleached fibres, such as jute or hemp, may no longer exhibit the above-mentioned color reactions, although' they "may have done so originally in the raw condition. 152 THE TEXTILE FIBRES. There are several reagents which are serviceable in micro- chemical tests on vegetable fibres, as they yield distinctive color reactions. With the iodin-sulphuric acid reagent * the principal fibres give the following reactions. (a) Blue colors: Cotton, Raw fibre from Hibiscus cannabinus, 11 " Calotropis gigantea (greenish blue to blue),. " flax fibre, Cottonized ramie, Raw sunn hemp (often copper-red), " hemp (greenish blue to pure blue). (b) Yellow to brown colors: Bombaoc cotton, Vegetable silk (occasionally greenish or greenish blue), Raw jute, " fibre of Abelmoschus tetraphyllos, tt U rena sinuata, " " " Bauhinia racemosa (blackish brown), " " Thespesia lampas, ( ( esparto (reddish brown), ' ' aloe (mostly reddish brown, sometimes greenish and even blue), New Zealand flax (yellow, green to blue, depending on the purification of the fibre). The fibres in the second class have their cellulose largely contaminated with lignin, and hence have somewhat of the character of woody tissue. It is to be remarked, however, that by treatment with nitric acid (or by boiling with caustic potash under pressure) these fibres lose most of the lignin which encrusts their tissues, and then exhibit the characteristics of ordinary cellulose; that is to say, they dissolve in Schweitzer's reagent, and are colored blue with the iodin-sulphuric acid reagent. Ammoniacal copper oxide f (Schweitzer's reagent) is another * For the preparation of this reagent see chapter xvii. f For the preparation of this reagent see chapter xvii. THE VEGETABLE FIBRES. 153 reagent which gives characteristic reactions with many vegetable fibres, as follows: (a) The fibres are almost completely dissolved:* Cotton, Cottonized ramie, Raw fibre of Hibiscus cannabinus, " " " Calotropis gigantea, " flax, ' ' hemp (only the bast cells dissolve, the accompanying parenchymous cells remain undissolved), ' ' sunn hemp. (b) The fibre becomes blue in color and is more or less swollen: Raw jute, ' f fibre of A belmoschus tetraphyllos, " " " Urena sinuata, " " " Bauhinia racemosa, " " Thespesialampas, " New Zealand flax, 11 fibre of Aloe perfoliata (slightly swollen), " ll Bromelia karatas (strongly swollen), ' ' l ' Sida retusa (becomes greenish at first, then blue and swells up). - (c) The fibre is colored without swelling: Vegetable silk (blue), Bombax cotton (blue), Raw esparto (bright green), Raw fibre of Cordia lalijolia (blue), " " Sterculia villosa (blue). A solution of anilin sulphate may be used to detect lignifica- tion in a fibre; this reagent gives the following color reactions: (a) The color of the fibre is not changed or but slightly: Cotton, Bombax cotton (very slight coloration), Cottonized ramie, also the bast cells of raw ramie. * With the exception of the external cuticle, the inner cell-wall, and dry pro- toplasmic residue. For the morphological alterations which the fibres undergo by treatment with this reagent see under the description of the separate fibres. 154 THE TEXTILE FIBRES. Raw flax, Raw bast fibres of Hibiscus cannabinus (very slight color- .ation), Raw bast fibres of Calotropis gigantea (very slight colora- tion), Raw sunn hemp, Raw New Zealand flax (very slight coloration), Manila hemp (very slight coloration), (b) The fibre is distinctly or very strongly colored: Vegetable silk (intense citron-yellow), Raw jute (golden yellow to orange), Raw bast fibres of Abelmoschus tetraphyllos (golden yellow), " " " " Urena sinuata (golden yellow), " " " " Sidaretusa (yellow), Raw bast fibre of Thespesia lampas (golden yellow), " " " Cordia latijolia (dull yellow), Raw hemp (pale yellow), Raw esparto (sulphur yellow), Raw fibre of Bromelia karatas (golden yellow). 5. Chemical Investigation of Vegetable Fibres. A chemical study of the fibres involves an examination of their chemical constituents. As already stated, though cellulose is the principal chemical compound to be found in vegetable fibres, yet there are certain other substances present, which at times may be characteristic of the fibre. Then, again, the cellulose which occurs in different classes of fibres appears to be somewhat dif- ferent in its chemical properties, which has led to the supposition of different forms of cellulose, already spoken of as ligno -cellulose, pecto-cellulose, etc. Though the chemistry of these bodies has been some w hat studied with reference to vegetable fibres by Cross and Bevan and a few others, yet the subject is still in a very crude condition, and there is much to be learnt in this field of chemical research. The methods for the chemical study of the vegetable fibres adopted by Cross, and continued by other chemists, may be stated in the following form: A separate portion of the fibre under examination is taken for each deter- THE VEGETABLE FIBRES. 155 mination, and the results are calculated into percentages on the dry weight of the substance. (1) Moisture. This may be called hygroscopic water or water of condition; it is obtained by drying a weighed portion of the fibre at 110 C. to constant weight. If dried at iooC., about i per cent, of the water will be retained. The percentage of hygroscopic moisture in the vegetable fibres varies considerably with the different state of humidity of the surrounding air, on which account it is recommended that the results of the analyses should be expressed on the dry weight of the fibre. It is inter- esting to note that the contents of hygroscopic moisture in a fibre appears to be an index of the susceptibility of attack by hydro- lytic agents, and that, the highest class of fibres are distinguished by their relatively low amount of moisture. (2) Ash. This is taken as the total residue left after ignition of the fibre, and represents the mineral constituents. The pro- portion of these is low in the ligno -celluloses and higher in the pecto -celluloses, especially when the proportion of non-cellulose is high. Admixture of cellular tissue with the fibre will also raise the amount of ash, as the cellular tissue contains a higher proportion of mineral constituents. (3) Hydrolysis. This refers to the loss of weight sustained by the fibre (a) on boiling for five minutes with a i per cent, solution of caustic soda, and (b) further loss of weight on con- tinuing to boil for one hour. The first loss in weight represents the proportion of fibre soluble in the alkali, the second represents the proportion of the fibre decomposed by actual hydrolysis. The pecto-celluloses are often so resolved by the action of the dilute alkali that most of the non-cellulose is dissolved away. The amount of hydrolysis of a fibre represents in some measure the power of resistance of a fibre to the action of the boiling-out and bleaching processes, as well as the power of resistance to actual wear as caused by frequent washings with alkalies, soaps, etc. (4) Cellulose. The determination of the value and composi- tion of the cellulose is made as follows: A sample of the fibre is first boiled for five minutes in a i per cent, solution of caustic soda, well washed, and then exposed for one hour at the ordinary 156 THE TEXTILE FIBRES. temperature to an atmosphere of chlorin gas; after which it is removed, washed, and treated with an alkaline solution of sodium sulphite, gradually raising to the boil. After several minutes the fibre is washed, and finally treated with dilute acetic acid, washed, dried, and weighed. The residue is taken as cellulose, and affords an important criterion as to the composition and value of the raw fibre (5) Mercerizing. This is represented by the loss in weight sustained by the fibre after treatment for one hour cold with a 33 per cent, solution of caustic potash. The action of the alkali often causes a considerable change in the structure of the fibre, especially with those fibres made up of a number of fibrils aggregated into bundles. (6) Nitration. This is represented by the increase in weight sustained by the fibre when treated for one hour with a mixture of equal volumes of nitric and sulphuric acids. Any change in color is also noted. (7) Acid Purification. This is represented by the loss in weight sustained by the fibre after boiling with 20 per cent, acetic acid, washing with alcohol and water, and drying. This treat- ment is intended to remove from the fibre all accidental impurities with a minimum alteration in composition. (8) Carbon Percentage. The fibre treated as above (7) is sub- jected to a combustion in the presence of chromic anhydride and sulphuric acid, and the resulting gas, composed of a mixture of carbon monoxide and dioxide, is collected and measured. As the two oxides of carbon have the same molecular volume, the amount of carbon in unit volume is independent of the composition of the gas. The amount of carbon in cotton cellulose (the typical cellulose) is 44.4 per cent.; the compound celluloses, however, have either a lower percentage in the one class (40 to 43 per cent.), or a higher percentage in the second class (45 to 50 per cent.), the pecto-celluloses being included in the first class and the ligno-celluloses in the second class. CHAPTER IX. COTTON. i. Historical. The use of cotton as a textile fibre dates back to antiquity, mention of it being found in the writings of Herodotus (445 B.C.).* It was used in India, Egypt, and China. The first European country to make cotton goods appears to have been Spain, f The use of cotton in India dates back to prehistoric times, and it is often referred to as early as 800 B.C. in the ancient laws of Manu.J It may be stated that from 1500 B.C. to about the * "There are trees which grow wild there (India), the fruit of which is a wool exceeding in beauty and goodness that of sheep. The Indians make their clothes of this tree-wool." (Herodotus, III, 106.) The same writer also refers to the clothing of Xerxes' army as being composed of "cotton fibre." (Herodotus, VII, 65-) t A rather ambiguous passage in the Historia Critica de Espana indicates that the manufacture of linen, silk, and cotton existed in Spain as early as the ninth century. De Maries states that cotton manufacture was introduced into Spain during the reign of Abderahman III., in the tenth century, by the Moors. In the fourteenth century Granada was noted for its manufacture of cotton. A commercial historiographer of Barcelona states that one of the most famous and useful industries of that city was the manufacture of cotton; its workers were united in a guild in the thirteenth century, and the names of two of its streets have preserved the memory of the ancient locality of their shops. There is much uncertainty as to when the manufacture of cotton was first introduced into Eng- land; the first authentic record of such is in Robert's Treasure of Traffic, pub- lished in 1641. t The following quotations are from the Books of Manu. The sacrificial thread of the Brahman must be made of cotton (karpasi), so as to be put over the head in three strings (Book II, No. 44). Let a weaver who has received 10 palas of cotton-thread give it back increased to n by the rice-water and the like used in weaving; he who does otherwise shall pay a fine of 12 ,panas (Book VIII, No. 397). Theft of cotton-thread was made punishable by fines of three times the value of the article stolen (Book VIII, No. 236). 15 8 THE TEXTILE FIBRES. same number of years after the Christian era, India was the centre of the cotton industry, and the cloth which was. woven in a rather crude and primitive manner has rarely been equalled for fineness and quality.* Cotton was introduced into China and Japan from India, but its adoption by these countries was slow.f It was probably introduced into China at the time of the conquest of this country by the Tartars, but it was not until about 1300 A.D. that the fibre was cultivated for manufacturing purposes.! In Egypt there is some question as to whether or not cotton was used except in rather late times, flax being the common article in that country for the manufacture of cloth. But there is evidently a good deal of confusion in the early writers respecting the terms used for "flax" and " cotton, " and it may be that * Two Arabian travellers of the middle ages, writing of India, say: "In this country they make garments of such extraordinary perfection that nowhere else are the like to be seen; these garments are woven to that degree of fineness that they may be drawn through a ring of moderate size." (Anciennes Relations des Indes et de la Chine, p. 21.) Marco Polo (Book III, ch. 21 and 28), about 1298 A.D., mentions India as producing "the finest and most beautiful cottons that are to be found in any part of the world." Tavernier, in his Travels, says of India that some calicos are made so fine that one can hardly feel them in the hand, and the thread when spun is scarcely discernible; that the rich have tur- bans -of so fine a cloth that 30 ells of it weigh less than 4 ounces. The poetic writers of the Orient call these cloths "webs of woven wind." There is the record of a muslin turban thirty yards in length, contained in a cocoanut set with jewels, which was so exquisitely fine that it could scarcely be felt by the touch. f Fesca (Japanischen Landwirthschajt, Pt. II, p. 485) says that cotton was introduced into Japan accidentally in the year 781 A.D. from India, but its cul- tivation was not continued. Several centuries later it was no doubt introduced again by the Portuguese; it was not, however, until the seventeenth century, during the reign of Tokugawa, that the cultivation of cotton became at all general in Japan. A great deal of cotton is now grown in Korea, having been introduced into that country from China about 500 years ago. The Korean cotton is of longer staple and of better quality than the Chinese cotton, as the soil and climate in Korea is better adapted to its growth. J Marco Polo (Rook II, ch. 24) gives no account of the culture of cotton in China, except in the province of Fo-Kien, but speaks of silk as being the custom- ary dress of the people. Herodotus states that the Egyptian priests wore linen clothes, but Pliny refers to them as also wearing cotton material, and Philostratus supports this latter statement. The words translated as "linen" do not always refer to the fibre of which the cloth was made, but often have reference to the general appearance of the material; therefore, cloth made from either flax or cotton alone, or mixed, COTTON. 159 the ancient Egyptians were better acquainted with the use of the cotton fibre than we imagine; we at least know that the cotton plant was grown there at a very early date. The use of cotton was evidently known to the Greeks* soon after the invasion of India by Alexander, though this does not signify that the Greeks themselves either grew the cotton plant or engaged in the manufacture of the fibre into clothes. The cotton plant does not appear to have been cultivated in Italy until some time after the Christian era, although a knowledge of the fibre and a probable use of the cloth made from it was no doubt known to them a long time previous, f For the real introduction into Europe of the cotton plant and the manufacture of the fibre into cloth we must look to the Mohammedans, who spread this knowledge throughout the countries bordering on the Mediter- ranean Sea during the period of their wide- spread conquests.! As to the knowledge and use of cotton in the Western Hemisphere, this seems to also have extended to very early times, for when Columbus first came to the West Indies in 1492, he- found cot- ton extensively cultivated, and the inhabitants of these islands wove cloth from the fibre. Among the Mexicans cotton was found to be the chief article of clothing, as these people did not possess either wool or silk and were not acquainted with the was called linen. Even the fact that all Egyptian mummy-cloths so far examined appear to consist of flax is no argument against the probable use of cotton by these people; it only proves that flax alone was employed for certain religious purposes, and cotton, wool, and silk may have been in common use for the cloth- ing of the people. * Aristobulus, a contemporary of Alexander, mentions the cotton plant under the name of the "wool-bearing tree," and states that the capsules of this tree contain seeds which are taken out, and the remaining fibre is then combed like wool. (Strabo, XV, i.) Nearchus, an admiral of Alexander, about 327 B.C., says: "There are in India trees bearing, as it were, bunches of wool. The natives made linen garments of it, wearing a shirt which reached to the middle of the leg, a sheet folded about the shoulders, and a turban rolled around the head. The linen made by them from this substance was finer and whiter than any other." (Arrian. Ind. y ch. 16.) t Miiller (Handbuch der Mas. Alterth. Wissensch., Vol. IV, p. 873) states that cotton cloth was used for clothing by the Romans prior to 284 A.D. J Abu Zacaria Ebn el Awam, a Moorish writer of the twelfth century, gives a full account of the proper method of cultivating the cotton plant, and also men- tions that cotton was cultivated in Sicily. 160 THE TEXTILE FIBRES. use of flax, although the plant grew in their country. * In Peru cotton was also in use from an early date, and at the time of Pizarro's conquest of that country in 1522 the inhabitants were clothed in cotton garments; cotton cloths have also been found oft Peruvian mummies of a very ancient date. Furthermore, the cotton plant is indigenous to Peru and from it is obtained a special variety known as Peruvian cotton. According to Ban- croft, the first attempt towards cotton cultivation in the Amer- ican colonies was in Virginia, during Wyatt's administration, in 1621. The first mill in the United States for the manufacture of cotton goods appears to have been erected at Beverly, Massa- chusetts, in 1787. The world's annual consumption of cotton at the present lime is about 6,500,000,000 Ibs. 2. Origin and Growth. The cotton fibre consists of the seed- hairs of several species of the genus Gossypium, belonging to the natural order of Malvace&.'f * Among the presents sent by Cortez to Charles V. of Spain were many fabrics made from cotton. t The following is a description of the botany of cotton given in Bulletin No. 33 of the U. S. Department of Agriculture: " The cotton plant belongs to the Malvacece, or the mallow family, and is known scientifically by the generic name Gossypiu*n. It is indigenous principally to the islands and maritime regions of the tropics, but under cultivation its range has been extended to 40 or more on either side of the equator, or to the isothermal line of 60 F. In the United State s latitude 37 north about represents the limit of economic growth. The Gossypium plant is herbaceous, shrubby, or arborescent, perennial, but in cultivation her- baceous and annual or biennial, often hairy, with long, simple, or slightly branched hairs, or soft and tomentose, or hirsute, or all the pubescence short and stellate, rarely smooth throughout; stem, branches, petioles, peduncles, leaves, involucre, corolla, ovary, style, capsule, and sometimes the cotyledons more or less covered with small black spots or glands. Roots tap-rooted, branching, long, and pene- trating the soil deeply. Stems erect, terete, with dark-colored ash-red, or red bark and white wood, branching or spreading widely. Branches terete or some- what angled, erect or spreading, or in cultivation sometimes very short. Leaves alternate, petioled, cordate, or subcordate, 3- to 7-, or rarely Q-lobed, occasionally some of the lower and upper ones entire, 3- to 7-veined. Veins branching and netted; the midvein and sometimes adjacent ones bear a gland one-third or ess the distance from their bases, or glands may be wholly absent. Stipules in pairs, linear-lanceolate, acuminate, often ceduous. Flowers pedunculate. Peduncles subangular or angular, often thickened towards the ends, short or very short, erect or spreading; the fruit is sometimes pendulous, sometimes glandular, bearing a leafy involucre. Involucre 3-leaved, or in cultivation some- COTTON. 161 The cotton plant is a shrub which reaches the height of four to six ft. It is more or less indigenous to nearly all subtropical FIG. 44. American Upland Cotton Shrub. (After Dodge.) countries, though it appears to be best capable of cultivation in warm, humid climates where the soil is sandy, and in the neighbor- times 4; bract eoles often large, cordate, erect,^ appressed or spreading at sum- mit, sometimes coalescent at base or adnate to the calyx, dentate or laciniate, sometimes entire or nearly so, rarely linear. Calyx short, cup-shaped, truncate, shortly 5 dentate or more or less 5 -parted. Corolla hypogynous. Petals 5, often coalescent at base and by their claws adnate to the lower part of stamen tube, obovate, more or less unequally transversely dilated at summit, convolute in bud. Staminal column dilated at base, arched, surrounding the ovary, naked below, above narrowed and bearing the anthers. Filaments numerous, filiform, simple or branched, conspicuous, exserted. Anthers kidney-shaped, i -celled, dehiscent by a semicircular opening into two halves. Ovary sessile, simple, 3- to 5-celled. Ovules few or many, in two series. Style clavate, 3- to 5-parted; divi- sions sometimes erect, sometimes twisted and adhering together, channelled, bearing the stigmas. Capsule more or less thickened, leathery, oval, ovate- 162 THE TEXTILE FIBRES. hood of the sea, lakes, or large rivers. It appears to thrive most readily in North and South America, India, and Egypt; it has FIG. 45. Sea-island Cotton Shrub. (After Dodge.) also been cultivated in Australia, but not as yet with any great degree of success; inferior qualities have been grown along the acuminate, subglobose, mucronate, loculicidally dehiscent by 3 to 5 valves. Seed numerous, subglobose, ovate or subovate, oblong or angular, densely covered with cotton or rarely glabrous. Fibre sometimes of two kinds, one short and closely adherent to the seed, the other longer, more or less silky, of single simple flattened cells more or less spirally twisted, more readily separable from the seed. Albumin thin, membranous, or none. Cotyledons plicate, auriculate at base enveloping the straight radicle. " COTTON. 163 coasts of Africa; that grown in Europe (Italy and Spain) is prac- tically negligible, as far as commercial considerations are con- cerned.* In America, India, and Egypt the cotton plant is annual * Monie (The Cotton Fibre} gives the following account of the cultivation of the cotton plant: "The plant, although indigenous to almost all warm climates, is nevertheless only cultivated within a very limited area for commercial pur- poses, the principal centres of cotton agriculture being in Egypt, the southern portions of the United States, India, Brazil, the west and southern coasts of Africa, and the West India Islands. A large amount of white cotton is raised in China, but this is almost entirely used in the home manufactures. The time when sow- ing is begun in the different districts varies considerably, being largely dependent on climatic influences. The seasons, however, are generally as follows: American. From the middle of March to the middle of April. Egyptian. From the begin- ning of March to the end of April. Peruvian and Brazilian. From the end of December to the end of April. Indian or Surat. From May to the beginning of August. In the various American plantations the sowing time begins and ends almost simultaneously, while in other countries, especially where the atmos- phere and climate are subject to much variation, the period of planting fluctu- ates; the plants in some parts being several inches above the ground, while in. other parts of the same country the fields may be only under preparation. When the sowing is finished, and before, and some time after the crop makes its appear- ance, keeping the ground free from weeds is the main object to be looked to, otherwise the soil would become much impoverished and the product would be of an inferior quality. In from eight days to a fortnight after sowing, the young shoots first appear above ground in the form of a hook, but in a few hours afterwards the seed end of the stalk or stem is raised out of the ground, disclos- ing two leaves folded over and closed together. The leaves and stems of these young plants are very smooth and oily and of a fleshy color and appearance, and, as before stated, extremely tender (see Fig. 530). In a short time after the plant has reached the stage shown in the illustration, it begins to straighten itself and deepen in color, or, rather, changes to a light oily green, while the two leaves gradu- ally separate themselves until they attain the forms shown in Fig. 53, b and c. When this stage has been reached its development is rapid, and proceeds in a similar form to ordinary shrubs until it reaches maturity. In examining the cotton plant from time to time during its growth some interesting and instruc- ive objects will be observed. Firstly, in regard to the formation of the leaves, it will be found that they vary in shape on different parts of the stem. Thus, for instance, on a Gallini Egyptian (G. barbadense) plant the lower leaves were entire, the centre or middle three-lobed, while the upper leaves were five-lobed. In the G. hirsutum species the lower leaves have five, and some three lobes, with the small branch petioles of a hairy nature, while the upper leaves are entire and undivided. In the Peruvian cotton plant the lower leaves are entire and of an oval shape, while the upper leaves have five acuminated lobes. Another interesting point observable in the growth of the cotton plant is the presence of a small cavity situated at the lower end of the main vein under each leaf. Through this opening, on warm days, the plant discharges any excess of the 1 64 THE TEXTILE FIBRES. in its growth, but in hot tropical climates, and in South America, it becomes a perennial plant and assumes more of a tree-like form. The leaf of the cotton plant has three-pointed lobes; FIG. 46. Leaf of the Cotton Plant. the flower has five petals, yellow at the base, but becoming almost white at the edges. The fruit of the cotton plant forms the cotton resinous matter which circulates through its branches. Before the plant attains its full height it begins to throw off flower-stalks, which are generally (when per- fectly formed) small in diameter and of considerable length; on the extremity of these stalks the blossom pod after a time appears, encased in three leaf-sheaths or calyxes, with fringes of various lengths. Gradually this pod expands until it attains to about the size of a bean, when it bursts and displays the blossom. This blossom only exists in full development for about twenty-four hours, when it begins to revolve imperceptibly on its axis and in about a day's time twists itself completely off. When the blossom has fallen, a small three-, and in some cases, five-celled triangular capsular pod of a dark -green color is disclosed, which increases in size until it reaches that of a large filbert. Meantime the seeds and filaments have been in course of formation inside the pod, and when growth is completed the expansion of the fibre causes it to burst into sections, in each cell of which, and adhering firmly to the surface of the seeds, is a tuft of the downy material." COTTON. 165 boll, which contains the seeds with the attached fibres. The boll consists of from three to five segments, and on ripening bursts open* and discloses a mass of pearly! white downy fibres (Fig. 49), in which are imbedded the brownish -black to black- colored cottonseeds. The cotton should be picked as soon as possible after ripening; the seeds are then separated from the FIG. 47. Leaf and Flower of Sea-island Cotton. (After Bulletin No. jj>, U. S. Dept. Agric.) fibres by a process known as ginning. Besides the fibre itself, nearly all of the other products of the cotton are now utilized * According to Heuze (Plantes Industrielks, vol. i, p. 139) the time required for' the maturity of cotton is divided as follows: From seeding to flowering, New Orleans 80 to 90 days sea-island TOO to no days; from flowering to maturity, New Orleans 70 to 80 days, and sea-island about 80 days, making the total period of growth about 5 to 6| months. i66 THE TEXTILE FIBRES. commercially.* The seeds are of especial value, as they contain a large quantity of oil, which is expressed and used for soap- FlG. 48. Leaf and Flower of India Cotton, Gossypium herbaceum. (After Bulletin No. jj, U. S. Dept. Agric.) * According to Bulletin No. jj (U. S. Dept. Agric.) the following is the pro- portion of the different parts of the cotton plant, calculated on the dried or water- free material: Part of the Plant. Weight. Per Cent. Ounces. Grams. Roots . . O.SI3 i-35 1.181 0.829 1-343 0.615 J 4-55 38.26 33.48 23-49 38.07 17-45 8.80 23-I5 20. 25 14.21 23-03 10.56 Sterns Leaves ..... Bolls Seed Lint (fibre) Total 5-83I 165.30 I OO . OO This table was compiled from the examination of a large number of plants and represents the average composition of the cotton plant as stated. COTTON. 4 I6 7 making and many other purposes, while the residuum of meal and hulls is converted into cattle foods and fertilizer.* The short FIG. 49. Sections of the Cotton Boll (Egyptian). (After Witt.) A, stem; B, calyx; C, capsule; Z>, seed; , cotton fibre. * The following table presents the fertilizing constituents in a crop of cotton yielding 100 Ibs. of lint per acre, expressed in Ibs. per acre. The weight of the total crop from the acre was 847 Ibs. Part of Plant. Nitrogen. Phos- phoric Acid. Potash. Lime. Magnesia. Roots (83 Ibs.) 0.76 0.43 1. 06 O. C3 o. 34 Stems (210 Ibs ) ? 20 I 20 3 OQ 2 12 O 02 Leaves (102 Ibs ) 6 16 2 28 3 46 8 <2 I 6? Bolls (us Ibs.') . 2 4? 1 . 3O 2 44. o 60 O <4. Seed (218 Ibs.) 6.82 2 . 77 2 CC o. ct; 1 . 2O O. 24 O. IO *'** 0.46 O. IQ 0.08 Total (847 Ibs.) 20.71 8.1 7 13.06 12.60 4-75 The following 'table presents the proximate constitutents of the various i68 THE TEXTILE FIBRES fibres, or nep, left on the seed after the first ginning are also recovered by a second process and are known as linters, which are used in the manufacture of cotton-batting, guncotton,* etc. The separation of seed-particles from the fibre is not always perfect, and they frequently make their appearance in gray calico in the form of black specks or motes, and as these contain small quantities of oil and tannin; matters which are pressed out into the surrounding fibres, they cause specks and uneven- ness in dyeing and finishing. If they come in contact with solu- tions or materials containing iron compounds, a violet stain will be produced, the color of which, however, may not develop for some months. Bowman (loc. cit.) gives an excellent description of the physiological development of the cotton fibre, f from which the parts of the cotton plant as given by analyses of a large number of samples by the United States Department of Agriculture: Part of Plant. Water. Ash. Protein. Fibre. Nitrogen- free Extract. Fat. Entire plant IO OO 12 OI 17 c:? 22 O4 2C II 41 r Roots IO OO 72 2 o 80 xig (-7 Stems IO OO ^ 9f)A 20 4C V*57 69 x o 7O 87 *'lt i ro Leaves IO OO 12 8? 2 1 64 12 C 7 16 82 3-5 6 oc Bolls . ... IO OO 4 no ic 80 Altf O / IO 72 4O7 Seed 9 02 A 74 IO 38 22 C 7 2 -3 QA IO 4C Lint 6 74 I 6c I CO **'yi 8^ 71 57O o 61 /y * With sea-island and Egyptian cottons the seed is entirely freed from lint by ginning, but with upland cottons the quantity of lint still adhering to the seed after it has passed through the gin amounts to about 10 per cent, of the total weight of the seed. An Experiment Station Report shows that the seeds from upland cotton after ginning consist of 54.22 per cent, of kernels (yielding 36.88 per cent, of oil and 63.12 per cent, of meal) and 45.78 per cent, of hulls (yield- ing 27.95 per cent, of linters and 72.05 per cent, residue); so that in the ginned seed there is present the following: Meal 34 . 22 per cent. Oil. 20.00 " " Hulls 35.78 " Linters 10 . oo " " According to Adriane (Chent. News, Jan., 1865) the seeds fom Egyptian cotton yield 37.45 per cent, of hulls and 62.55 P er cent - f kernels. t The following remarks relative to the development of the cotton fibre from the seed are taken from Bulletin No. jj (vide supra): " If a very immature COTTON. 169 following is quoted: "In their earliest stages the young cotton fibres appear to have a circular section arising from the com- parative thickness of the tube-walls; but as these walls gradually become thinner by the longitudinal growth of the hair and the pressure to which they are subjected by the contact of surround- ing fibres enclosed within the pod, they gradually become flat- Tic. 50. Typical Cotton Fibres. (X3OO.) -<4> normal fibre showing regular twists; B, straight fibre without twists; <7, a knot or irregularity in growth of fibre. (Micrograph by author.) tened, and just before the pod bursts the outer walls of the cells have become so attenuated in the longest fibres as to be almost invisible even under high microscopic powers, and present the cotton boll be cut transversely, the cut section will show that it is divided by longi- tudinal walls into three or more divisions, and the seeds will be shown attached to the inner angle ot each division. The seeds retain this attachment until they have nearly reached their mature size and the growth of lint has begun on them, when their attachments begin to be absorbed, and by the increased growth of the lint the seeds are forced into the centre of the cavity. The development of the fibre commences at the end of the seed farthest from its attachment and gradually spreads over the seed as the process of growth continues. The first appearance of the cotton fibre occurs a considerable time before the seed has attained its full growth and commences by the development of cells^from the surface of the seed These cells seem to have their origin in the second layer of cellular tissue, and force themselves through the epidermal layer, which seems to be gradually absorbed The cells which originate the fibre are characterized by the thickness of their cell-walls when compared with their diameter." lyo THE TEXTILE FIBRES. appearance of a thin, pellucid, transparent ribbon. With the bursting of the pod, however, a change occurs. The admission of air and sunlight causes a gradual unfolding of the hairy plexus, and the rapid consolidation of the liquid cell-contents on the inner surface of the cell- wall gives them a greater thickness and density, which is further increased by the gradual shrinking- in of the walls themselves upon the cell-contents. There is also a gradual rounding and thickening of the fibre, which in- creases by the deposition of matter on the inner wall of the cell. FIG. 51. Typical Cotton Fibres. (X 300.) A, broad flat fibre near base; J?, thick rounded fibre; C, fibre near pointed end; D, cut end of fibre. (Micro- graph by author.) As this action is not perfectly uniform, arising from the unequal exposure of different parts of the fibres to light and air, it causes a twisting of the hairs, which is always a characteristic of cotton when viewed under the microscope, and the flat collapsed por- tions of the tube form so many reflecting surfaces, to which the brightness of the fibre when stretched tight in the fingers is no doubt due. Another change also occurs at this stage, a change which corresponds to the ripening of fruiU In the earliest period of their formation the growing cells are 'filled with juices which are more or less astringent in character. Under the influence of light and air these cell contents undergo a chemical change, COTTON. 171 in which the astringent principles are replaced by more or less saccharine or neutral juices, until in the perfectly ripe cotton fibre the cell- walls are composed of almost pure cellulose." The cell- wall of the cotton is thin in comparison with that of the bast fibres, but in comparison with the other seed-hairs it is remarkably thick. This accounts for its much greater strength over the latter. In completely developed fibres the thickness of the cell- wall is from one-third to two-thirds of the total thick- ness of the fibre itself. The quality of the cotton fibre depends not only on the species of the plant from which it is derived, but also on the manner FIG. 52. Cotton Bolls. of its cultivation. The conditions which exercise, perhaps, the greatest influence are: (a) the seed, (b) the soil, (c) the mode of cultivation, (d) the climatic conditions.* The seed for sowing must be carefully and specially chosen for the purpose. A * It is said that the best average daily temperature for the growth of cotton is from 60 to 68 F. for the period from germination to flowering, and fiom 68 to 78 F. from flowering to maturity. According to Dr. Wight (Jour. Agr. Hort. Soc. India, vol. 7, p. 23), for the proper maturing of the best qualities of American cotton an increasing temperature during the period of greatest growth is required; the failure to produce in India a quality of fibre equal to the American product from the same kind of seed is attributed to the fact that in the climate of the former country there exists a diminishing rather than an increasing average daily tem- perature. 172 THE TEXTILE FIBRES. very dry soil produces harsh and brittle cotton, the fibres of which are very irregular in length; a moist and sandy soil pro- duces a very desirable cotton of long and fine staple.* The best soil is considered to be a light loam, while a damp clay is regarded as the worst. Soils situated in proximity to the sea, and there- fore containing considerable saline matter, appear to furnish the most valuable varieties of cotton, and it is claimed that the a b c FIG. 53. The Cotton Plant in the Early Stages of its Growth. saline constituents of the soil have considerable influence on the growth and development of the cotton fibre. 3. Varieties of Cotton.f The classification of the different * An excess of rain causes the plant itself to grow too rapidly and luxuriantly at the expense of the fruit and consequently there is less fibre produced. A long drought causes a stunted growth of the plant, but few bolls are produced, and 'these ripen prematurely. f The various names given to the cotton fibre in different countries may be of interest; they are as follows: India Pucu Spain Algodon Yucatan and ancient Mexico Ychcaxihitvitl Tahiti Vavai France Coton Italy Cotone Germany Baumwolle Persia. . . = Pembeh or Poombeh Arabia Gath, Kotan, or Kutn Cochin China Cay Haung China Hoa mein Japan Watta ik or Watta noki Siam Tonfaa Hindoostan Nurma Mysore and Bombay Deo Kurpas and Deo Kapas Mongolia Kohung COTTON. 173 species of cotton plant varies with different authorities; the most comprehensive, perhaps, is to classify the different varieties of the cotton plant as (i) the tree, (2) the shrub, and (3) the her- baceous species.* According to Parlatore all commercial cotton * The following is a list of species of the cotton plant more or less recognized by botanists: Gossypium album Hamilton, a synonym of G. herbaceum; commercially known as upland cotton: has a white seed. G. arboreum Linn., a tree-like plant; perennial; indigenous to India; pro- duces but little fibre. G. barbadense Linn., indigenous to America and outlying islands; gives the highly prized sea-island cotton. G. brasiliense Macfad., a tropical species; belongs to the so-called "kidney cottons"; the seeds adhere to one another in clusters. G. chinense Fisch. & Otto, a synonym for G. herbaceum; a Chinese cotton. G. croceum Hamilton, a synonym for G. herbaceum; possesses a yellow lin'v. G. eglandulosum Cav., a synonym for G. herbaceum. G. elatum Salisb., a synonym for G. herbaceum. G. jructescens Lasteyr., a synonym for G. barbadense. G. juscum Roxb., a synonym for G. barbadense. * G, glabrum Lam., a synonym for G. barbadense. G. glandulosum Steud., a synonym for G. herbaceum. G. herbaceum Linn., usually considered of Asiatic origin; synonymous with G. hirsutum; ordinary upland cotton. G. hirsutum Linn., of American origin; Georgia upland cotton. G. indicum Lam., a synonym for G. herbaceum. G. jamaicense Macfad., a synonym for G. barbadense; grows in Jamaica. G. javanicum Blume, a synonym for G. barbadense; grows in Java. G. latijolium Murr., a synonym for G. herbaceum. G. leonivum Medic., a synonym for G. herbaceum. G. macedonlcum Murr., a synonym for G. herbaceum. G. maritimum Tod., a synonym for G. barbadense. G micranthum Cav., a synonym for G. herbaceum. G. molle Mauri, a synonym for G. herbaceum. G. nanking Meyen, a synonym for G. herbaceum G. neglectum Tod., indigenous to India; similar to G. aboreum; extensively grown in India; gives the Dacca and China cottons. G. nigrum Hamilton, a synonym for G. barbadense. G. obtusijolium Roxb., a synonym for G. herbaceum. G. oligospermum Macfad., a synonym for G. barbadense. G. paniculatum Blanco', a synonym for G. herbaceum. G. perenne Blanco, a synonym for G. barbadense. G. peruvianum Cav., a synonym for G. barbadense. G. punctatum Schum. & Thonn., a synonym for G. barbadense. G. racemosum Poir, a synonym for G. barbadense. G. religiosum Par., a synonym for G. arboreum; so called because its use is 174 THE TEXTILE FIBRES. is derived from seven species of the Gossypium, which he enumerates as follows: * (i) G. barbadense^ which comprises the long-stapled and mostly restricted to making turbans for Indian priests; also because it grows in the gardens of the temples; it has the cultural name of Nurma or Deo cotton. Also a variety of G. barbadense. G. roxburghianum Tod., a variety of G. neglectum; corresponds to the Dacca cotton of India. G. siamense Tenore, a synonym for G. herbaceum. G. sinense Fisch., a synonym for G. herbaceum. G. stocksii Masters, a synonym for G. herbaceum; claimed to be the original of all cultivated forms of this latter species. G. strictum Medic., a synonym for G. herbaceum. G. tomentosum, indigenous to the Hawaiian Islands; the bark is used for making twine. G. tricuspidatum Lam., a synonym for G. herbaceum. G. vitijolium Lam., a synonym for G. barbadense. G. vitijolium Roxb., a synonym for G. herbaceum. G. ivightianum Tod., a synonym for G. herbaceum; claimed by Todaro to be the primitive form of the Indian cottons. * Filippo Parlatore, Le specie dei cotoni, 1866. t The botany of this species is given as follows: Shrubby, perennial, 6 to 8 feet high, but in cultivation herbaceous and annual or biennial, 3 to 4 feet high, gla- brous, dotted with more or less prominent black glands. Stems erect, terete, branching. Branches graceful, spreading, subpyramidal, somewhat angular, ascending, at length recurving. Leaves alternate, petiolate, as long as the petioles, rotund, ovate, subcordate, 3- to 5-lobed, sometimes with some of the upper and lower leaves entire, cordate, ovate, acuminate; lobes ovate, ovate-lanceolate, acute or acuminate, channelled above, sinus subrotund, above green, lighter on the veins, glabrous, beneath pale green and glabrous, 3- to 5 -veined, the mid- vein and sometimes one or both pairs of lateral veins bearing a dark -green gland near their bases. Stipules erect or spreading, curved, lanceolate-acuminate, entire or somewhat laciniate. Peduncles equal to or shorter than the petiole, erect, elongating after flowering, rather thick, angled, sometimes bearing a large oval gland below the involucre. Involucre 3-parted, erect, segments spreading at top. many veined, broadly cordate-ovate, exceeding half the length of the corolla, 9 to 12 divided at top, divisions lanceolate-acuminate. Calyx much shorter than the involucre, bracts cup-shaped, slightly 5 -toothed or entire. Corolla longer than the bracts. Petals open, but not widely expanding after flower- ing, broadly obovate, obtuse, crenate, or undulate margined, yellow or sulphur colored, with a purple spot on the claw, all becoming purplish in age. Stamen about half the length of the corolla, the tube naked below, anther bearing above. Style equal to or exceeding the stamens, 3 to 5 parted. Ovary ovate, acute, glandu- lar, 3-, rarely 4- to 5-celled. Capsule a little longer than the persistent involucre, oval, acuminate, green, shining, 3-, rarely 4- to 5-valved. Valves oblong or ovate- oblong, acuminate, the points widely spreading. Seeds 6 to 9 in each cell, obovate. COTTON. 175 silky -fibred cottons known as Barbadoes, sea-island, Egyptian, and Peruvian. The plant reaches a height of from 6 to 8 feet, and has yellow blossoms. Owing to variations in the conditions of its cultivation, however, the present sea-island cotton has changed considerably from the original barbadense* This variety is employed for the spinning of fine yarns, such as are known in trade as "Bolton counts." (2) G. herbaceum,-f including most of the cotton from India, narrowed at base, black. Fibre white, 3 to 4 or more times the length of the seed, silky, easily separable from the seed. Cotyledons yellowish, glandular, punctate. * The following species are considered as synonyms of G. barbadense: G. jruc- tescens Lasteyr., G. juscum Roxb., G. glabrum Lam., G. jamaicense Macfad., G. javanicum Blume, G. maritimum Todaro, G. nigrum Ham., G. oligospermum Macfad , G. perenne Blanco, G. peruvianum Cav., G. punctatum Schum. & Thonn, G. racemosum Poir., G. religiosum Par., and G. vitijolium Roxb. f The descriptive botany of this species is as follows: Shrubby, perennial, but in cultivation herbaceous, annual or biennial. Pubescence variable, part being long, simple or stellate, horizontal or spreading, sometimes short, stellate, abundant, or the plants may be hirsute, silky, or all pubescence may be more or less wanting, the plants being glabrous or nearly so. Glands more or less prominent. Stems terete, or somewhat angular above, branching. Branches spread- ing or erect. Leaves alternate, petioled, the petioles about equalling the blades, cordate or subcordate, 3- to 5-, rarely y-lobed. Lobes from oval to ovate, acu- minate, pale green above, lighter beneath, more or less hairy on the vein, 3- to 5- o y-veined, the midvein and sometimes the nearest lateral veins glandular towards the base or glands wanting. Sinus obtuse. Lower leaves sometimes cordate, acuminate, entire, or slightly lobed. Stipules erect or spreading, ovate-lanceo- late to linear-lanceolate, acuminate, entire, or occasionally somewhat dentate. Peduncles erect in flower, becoming pendulous in fruit. Involucre 3-, rarely 4-parted, shorter than the corolla, appressed, spreading in fruit, broadly cordate, incisely serrate, the divisions lanceolate-acuminate, entire or sometimes sparingly dentate. Calyx less than half the length of the involucre cup-shaped, dentate, with short teeth. Petals erect, spreading obovate or cuneate, obtuse or emar ginate, curled or crenulate, white or pale yellow, usually with a purple spot near the base, in age becoming reddish. Stamens half the length of the corolla. Pis- til equal or longer than the stamens. Ovary rounded obtuse or acute, glandular, 3- to 5 -celled. Style about twice the length of the ovary, 3- to 5-parted above, the glandular portion often marked with 2 rows of glands. Capsule erect, glo- bose or ovate, obtuse or acuminate, mucronate, pale green, 3- to 5 -celled. Valves ovate to oblong, with spreading tips. Seed 5 to 1 1 in each cell, tree, obovate to subglabrous, narrowed at base, clothed with two forms of fibre, one short and dense, closely enveloping the seed, the other 2 to 3 times the length of the seed, white, silky, and separating with some difficulty. Cotyledons somewhat glandular, punctate. 176 THE TEXTILE FIBRES. southern Asia, China, and Italy.* It is an annual plant growing from 5 to 6 feet in height; unlike the barbadense variety, its seeds are generally covered with a soft undergrowth of fine down, which is an objectionable feature. The flower is yellow in color. This species is perhaps the hardiest of the cottons, and is cultivated over a wider range of latitude.f It forms the source of nearly all the Indian cotton. J It is used for the spinning of low-count * Parlatore claims that this species originated in India, while Todaro says that it is spontaneous in Asia and perhaps also in Egypt, and that G. wightianum is the primitive form of the Indian cottons; others still consider it as a native of Africa. According to Bulletin No. 33 (U. S. Dept. Agric.), it is probable that G. herbaceum is not a definite species, but has been developed by cultivation from perhaps several wild species, and it represents not a species but a group of hybrids and forms more or less closely related. t The following species are considered as synonyms of G. herbaceum : G. album Ham., G. chinense Fisch., G. croceum Ham., G. eglandulosum Cav., G. elatum Salis., G. glandulosum Steud., G. hirsutum Linn., G. indicum Lam., G. latifolium Murr., G. leoninum Medic., G. macedonicum Murr., G. micranthum Cav., G. molle Mauri, G. nanking Meyen, G. obtusijolium Roxb., G. paniculaium Blanco, G. punc- tatum Guil., G. religiosum Linn., G. siamense Tenore, G. sinense Fisch., G. stric- tum Medic., G. tricuspidatum Lam., and G. vitifolium Roxb. J Todaro claims that the species G. wightianum is the form chiefly cultivated in India. It differs from the general form of G. herbaceum in that the latter has broader and more rounded leaves, and broader, thinner, and deeper cut brac- teoles. The botany of G. wightianum is as follows: Stems erect, somewhat hairy, branches spreading and ascending. Leaves, when young, densely covered with short thick, stellate hairs, becoming nearly glabrate in age; ovate-rotund, scarcely cordate, 3- to 5-, rarely y-lobed; lobes ovate, oblong, acute, constricted at base into a rounded sinus. Stipules on the peduncles almost ovate, others linear-lanceolate, acuminate. Flowers yellow with a deep purple spot at base, becoming reddish on the outside in age. Bracteoles small, slightly united at base, ovate, cordate, acute, shortly toothed. Peduncles erect in flower, recurved in fruit, one-quarter the length of the petioles. Capsule small, ovate, acute, 4-celled, with 8 seeds in each cell. Seeds small, ovate, subrotund, clothed with two forms of fibre, the inner short and closely adhering, the other longer, white or reddish. There is another very similar form indigenous to India known as G. neglectum, it grows as a large bush, and its fibre constitutes the majority of the commer- cial Bengal cotton. Its botany is as follows: Stem erect. Branches slender, graceful, spreading. Leaves, lower ones 5 to 7 palmately lobed, segments lanceo- late, acute, rarely bristle-tipped, sinus rounded, the small lobes in the sinuses less distinct than in G. arboreum, upper leaves 3-parted, Stipules next the ped- uncles semiovate, dentate, the others linear-lanceolate, acute. Peduncles, with short lateral branches, 2 to 4 flowered. Involucral "bracts coalescent at base, deeply and acutely laciniate. Petals less than twice the length of the involucral COTTON. 177 yarns, also for the making of condenser yarns for the manufac- ture of flannelettes. (3) G. hirsutum* including most of the cotton from the southern United States, also known as upland cotton. The plant is shrubby in appearance, seldom reaching more than 7 feet in height; like the preceding variety, the seeds are also covered with a fine undergrowth of down. (4) G. arboreum^ including the cotton from Ceylon, Arabia, bracts, obovate, unequally cuneate, yellow, with a deep purple spot at base. Stamen-tube half the length of the corolla, naked at base. Capsule small, ovate, acute, cells 5- to 8-seeded, seed obovate, small, clothed with two forms of fibre, one very short, closely adherent, and of an ashy green color, the other longer, rather harsh, white. * Todaro claims that this species originated in Mexico, whence it has been spread by cultivation throughout the warmer portions of the world; to this form he also ascribes the Georgia or long-stapled upland cotton. Parlatore, on the other hand, considers it as indigenous to the islands in the Gulf of Mexico as well as the mainland, and that all green-seeded cotton, wherever cultivated, originated from this form. t The descriptive botany of this species is as follows: Shrubby, perennial, but in cultivation sometimes annual or biennial; tomentose, with two forms of hairs, one long and simple, the other more numerous, shorter, and stellate; glands small, scarcely prominent, more or less scattered. Stem erect, terete, very branch- ing. Branches spreading, terete. Leaves alternate, petiolate, with petioles a little shorter than the blade, subcordate, 5- to y-lobed, lobes oblong-lanceolate or lanceolate-acuminate, bristle -tipped, scarcely channelled above; sinus obtuse, often with a small lobe in some of the sinuses, beneath pale green and softly pubes- cent, 5- to 7-veined, the mid vein and often the two adjacent ones with a red- dish-yellow gland near their base; upper leaves palmately 3- to 5-lobed, lobes short. Stipules erect, spreading, lanceolate-acuminate. Peduncles axillary, erect before and spreading or horizontal after flowering and drooping in fruit, about three-fourths the length of the petioles, terete, destitute of glands, i to 2 usually i -flowered, jointed above the middle, bearing a small leaf and two stipules at this point. Involucre three-parted, appressed or scarcely spreading at summit, many nerved, broadly and deeply cordate, ovate-acuminate, 5 to 9, rarely 3 dentate or nearly entire. Calyx much shorter than the bracts, subglo- bose, truncate, crenulate or subdentate, with a large gland at the base within the involucre. Corolla campanulate, petals erect or spreading, broadly cuneate, subtruncate, crisp or crenulate, purple or rose-colored, with a large dark purple spot at the base. Stamina! tube about half the length of the corolla. Pistils equally or a little longer than the stamens. Ovary ovate, acute, glandular, usu- ally 3-celled. Style a little longer than the ovary, 3-parted without glands. Cap- sule pendulous, a little longer than the persistent involucre, ovate, rounded, glandular, 3- to 4-celled, and valved. Valves ovate, oval, spreading, mucronate- 178 THE TEXTILE FIBRES. etc. As the name indicates, it is a tree-like plant, and grows from 12 to 1 8 feet in height. The fibres are of a greenish color and very coarse; its flowers are of a reddish color.* (5) G. peruvianum, including the native Peruvian and Bra- zilian cottons. This differs from other varieties of cotton in that it is a perennial plant; the growth from the second and third years, only, however, is utilized. (6) G. tahitense, found chiefly in Tahiti and other Pacific islands. (7) G. sandwichensc, occurring principally in the Hawaiian Islands. This classification is claimed to include all the commercial varieties of cotton; it is probable, however, that the last two can be included under the bar ba dense and hirsutum varieties, as they possess the same characteristics as these fibres.f Other authorities on the botany of the cotton plant have rec- ognized many more species than those above described. Agos- tino Todaro % has described 52 varieties, while the Index Kewen- sis records 42 distinct species and refers to 88 others which it classifies as synonyms. Hamilton reduces the number of species to three, namely, the white-seeded, black-seeded, and yellow- linted, assigning to these species the botanical names album, nigrum, and croceum. The chief difficulty experienced in the botanical classification of the cotton plant is the fact that it hy- bridizes very readily and has a tendency to suffer alteration acuminate, the mucro recurved. Seed 5 to 6, ovate, obscurely angled, black. Fibre two forms, one white, long, overlying a dark green or black down; not readily separable from the seed. * A synonym of this species is G. religiosum; it appears to be indigenous to India. The plant is perennial and lasts from five to six years, and though the fibre is fine, silky, and of good length, yet there is but little of it produced. t Dr. Royle reduces the number of species of the cotton plant to the following four: (1) Gossypium arbor eum. (2) herbaceum. (3) barbadense. , (4) hirsutum. J Rel. sulla coltura dei cotoni in Italia, 1877-78, vol. 2, pp. 1057 and 1058. Bulletin No. jj (vide supra) makes the following remarks relative to the sub- ject of the cross-fertilization of cotton. The flower of the cotton plant is so large COTTON. 179 in variety with change in the conditions of its cultivation or variation in the character of the soil or climate.* Besides the varieties of cotton above enumerated, which are practically all which find any important commercial application, there is another plant which yields a fibre somewhat similar to cotton, and known as the silk-cotton plant. It belongs to the same natural order, Malvacea, as the ordinary cotton plant, but is of a different genus, being Salmalia instead of Gossypium. It grows principally on the African coast and in some parts of tropical Asia. The plant is rather a large tree, reaching from 70 to 80 feet in height. The blossoms are red in color, and the seeds are covered with long silky fibres, which are not adapted, however, for spinning. Although fibres from the different species of the cotton plant all possess the same general physical appearance, nevertheless, and develops so rapidly that cross-fertilization is easily secured. Flowers which are to be fertilized should be among those which are developed early in the sea- son, and should always be those on healthy and vigorous plants. The flowers to be operated upon should be selected late in the afternoon; one side of the unopened bud should be split lengthwise with a sharp knife having a slender blade, and the stamens removed. The anthers, the fertilizing parts of the sta- mens, will be found well developed and standing well away from the pistil, though not yet so matured as to be discharging pollen. These can be readily separated from their support by a few careful strokes of the knife, and the emasculated flower should then be enclosed in a paper bag to prevent access of pollen from unknown sources. The following morning the pistil will be fully developed and ready to receive pollen. A freshly opened flower from a healthy plant of the variety which it is desired to use in making the cross is picked and carried to the plant which was treated the previous evening, the bag is removed from the prepared flower, and by means of a camel-hair brush pollen is dusted over the end and upper part of the pistil. The paper bag is then replaced and allowed to remain two days, after which it should be removed. * In Europe cottons are graded according to their value as follows: i. Long Georgia. a. Makko. 3. Pernambuco. 4. Louisiana. 5. Cayenne. 6. New Orleans. 7. Short Georgia. 8. Surat. 9. Bengal. i8o THE TEXTILE FIBRES. there are characteristic features in each worthy of careful obser- vation. Gossypium barbadense: Sea-island. This constitutes the most valuable, perhaps, of all the different species. Its chief points of superiority are (a) its length, being more than half an inch longer than the average of other cottons; (b) its fineness of staple; (c) its strength; (d) its number of twists, which allow it to be spun to finer yarns; (e) its appearance, it being quite soft and silky. It is also characterized by a light-cream color. Sea-island cotton is mostly used for the production of fine yarns ranging from i2o's to soo's; * it is said that as fine as 2Ooo's has been spun from it.f On account of its adaptability for mercer- izing it is also largely employed for this purpose, in which case much coarser yarns are often prepared from it. Owing to the wide cultivation of sea-island cotton at the present time, for its growth is no longer strictly confined to the islands of the sea,t it is difficult to make a definite statement as to its length of staple , as this will vary considerably with the method and place of cul- *The "count" of cotton yarn means the number of hanks of 840 yards each contained in i Ib. The size lao's, for instance, means cotton yarn of such fineness that 120 hanks of 840 yards (= 100,800 yards) weigh i Ib. The French method of numbering is based on the decimal system, and the count means the number of hanks each 1000 meters in length required to weigh 500 grams. In order to change from French to English count, multiply the former by 0.847, or . The Belgian method of counting is to use the number of 84O-yard hanks in 500 grams. The Austrian system is the number of hanks of 950 ells each con- tained in 500 grams. The English system is the one mostly used, being employed in England, America, India, Germany, Italy, and Switzerland, and even in parts of Austria. Doubled or twisted yarns are designated in the same manner as single yarns, except that the number of threads is also given, for instance, if two single threads of count 20 are twisted together, the yarn is described as 2-20*3 or -$, or *; a three-ply yarn would be 3-20*3, or -fa or -^, etc. According to the number of threads twisted together, yams will lose from 2.5 to 6 per cent, of their length in doubling, and, of course, become correspondingly thicker. Yarns containing more than two single threads are known as sewing twist or cord. f See Monie, Structure of the Cotton Fibre, p. 40, as authority for this state- ment. A thread of such fineness would not be commercial, and has never been prepared, except, perhaps, in an experimental manner. % Some writers claim that sea-island cotton is peculiarly of American origin; that it was found on the island of San Salvador by Columbus, and by him brought to Spain. Other writers, among whom is Masters (Jour. Linn. Soc., vol. 19, p. 213), assert that this cotton is of central African origin. COTTON. 181 tivation.* The maximum length, however, may be taken as 2 inches, and the minimum as if inches, with a mean of if inches. Florida sea-island cotton is very similar in general characteristics to sea-island proper, possessing about the same mean length of staple, but being somewhat less in the maximum length. f Both of these varieties of sea-island show a maximum diameter of 0.000714 inch, a minimum of 0.000625 inch, and a mean of 0.000635 inch. Fiji sea-island is less regular in its properties than the two preceding varieties, and though its maximum length is somewhat greater than sea-island itself, yet the mean length is about the same, as is also the diameter. This cotton, however, has a very irregular staple and contains a large percentage of imperfect fibres, \\hich causes the waste to be rather high. The number of twists in the fibre is also less and does not occur as regularly. Gallini Egyptian cotton is sea-island cotton grown in Egypt, t It is somewhat inferior to the American varieties in general properties.! It pos- sesses a yellowish color, which distinguishes it from the product of all other countries. || The maximum length of the fibre is if * Sea-island cotton may be cultivated in any region adapted to the olive and near the sea, the principal requisite being a hot and humid atmosphere, but the results of acclimatization indicate that the humid atmosphere is not entirely necessary if irrigation be employed, as this species is undoubtedly grown exten- sively in Egypt. As a rule, the quality of the staple increases with the proximity to the sea; but there are exceptions to this rule, as that grown on Jamaica and some islands is of rather low grade, while the best fibre is produced along the shores of Georgia and Carolina, (Bulletin No. 33, U. S. Dept. Agric.) t Sea-island cotton gives a smaller yield of lint than any variety of cotton grown in America, but, on account of the greater length and fineness of staple, it has a much higher market value. t The Bamia variety of Egyptian cotton is a form of sea-island cotton to which Todaro has given the varietal name of polycarpum. It is characterized by numer- ous flowers springing from a single axil, and an erect, slightly branching habit, hence giving a large yield per acre. It was once thought that the Bamia cotton was a hybrid between okra and cotton, but in a Kew Report (1887, p. 26) this is shown to be incorrect. Gallini cottons have the bad feature of containing considerable undeveloped and short fibre, and this somewhat lessens its commercial value. Peruvian sea- island also possesses this same defect, but, in addition, contains usually quite a large amount of foreign matter, such as broken leaf, sand, seed particles, etc. || The fibre of Egyptian cotton is especially adapted to the manufacture of hosiery yarns and yarns for mercerizing. The United States imports Egyptian cotton to the value of about $10,000,000 per year. 1 82 THE TEXTILE FIBRES, inches, the minimum ij inches, and the mean ij inches. The fibres differ very little in their diameter, the average being 0.000675 inch. Peruvian sea-island is somewhat coarser in structure than the sea-island proper, being more hairy in ap- pearance; it has a slight golden tint. In staple it varies from if inches in length to if inches, with a mean of ij inches. Tahiti sea-island resembles the Fiji variety very closely; it has a creamy color. The length of staple varies from i J to if inches, with a mean of i J inches. It shows a considerable percentage of imperfect fibres due to a short undergrowth on the seed. Its average diameter is 0.000641 inch. Gossypium herbaceum.* Smyrna cotton is grown principally in Asiatic Turkey. It has a rather characteristic appearance under the microscope, being very even in its diameter but irregu- lar in its twist, showing many fibres where the twist is almost entirely absent. In length the staple varies from j to i| inches, with a mean of i inch; the mean diameter is about 0.00077 inch. Brown Egyptian cotton is supposed to be indigenous to that country, f It is characterized by a fine golden color, and great * The cultivated cottons of to-day are far different from the original form of the G. herbaceum, which gave only 28 to 29 per cent, of fibre, with a staple ao to 30 mm. long. The proportion of fibre has been greatly increased, reach- ing as high as 36 and even 40 per cent, in some varieties, while the length of staple has increased correspondingly, sometimes reaching fully three times its original length. f The first variety. of cotton to be cultivated in Egypt was called Makko-Jumel; this went through many changes and evolutions, and gradually changed its color to a yellowish brown, the new variety being known as Ashmouni, from the valley of Ashmoun, where the change was first noticed. The principal varieties of Egyptian cotton now grown are the Ashmouni, Mitafifi, Bamia, Abbasi, and Gallini. Formerly the Ashmouni formed the bulk of the Egyptian crop, but it is now almost entirely superseded by the Mitafifi. In color it is a light brown, and its staple is over an inch in length. The Mitafifi cotton is said to have been discovered by a Greek merchant in a village of that name; it is characterized by the seed having a bluish-green tuft at the extremity. Its color is a richer and darker brown than the Ashmouni; the fibre is long, strong, and fine, and very desirable in the market. The Bamia cotton is the next most extensively cultivated; the fibre is poor compared with the foregoing, being light brown in color and not very strong. The Abbasi cotton is of rather recent introduction; in its general properties it resembles Mitafifi, but has not the same strength. The Gallini cotton was derived from sea-island, but it has almost entirely disappeared COTTON 183 toughness and tensile strength. It is, however, shorter and coarser than the Gallini cotton. In length of staple it varies from ij to ij inches, with a mean of ij inches; the mean diameter is 0.000738 inch. African cottons are all derived from the her- baceum species. These cottons have a slight brownish tint,) and always contain a large amount of short fibres. The fibres also vary much in diameter and thickness of the tube-walls, and many exhibit a transparent appearance under the microscope. Yarns made from these cottons are always uneven on the surface. The length of staple varies from } to i J inches, with an average of i inch; the mean diameter is 0.00082 inch. Hingunghat cot- tons are Indian varieties; the quality of these varies with the soil and climate of the province in which they are grown. As a rule, they are of rather inferior grade; the best variety is the Surat cotton. Under the microscope the Hingunghat cotton shows much variation in diameter, although it possesses fewer twists than the better grades of cotton, yet, unlike the African varieties, it shows very few fibres without any convolutions at all. In length of staple it varies from J to ij inches, with a mean of i inch; the average diameter is 0.00084 inch. Broach, Tinnevelly, Dharwar, Oomrawuttee, DJwllerah, Western Madras, Comptah, Bengal, and Scinde are other varieties of Indian cotton, all be- longing to the herbaceum species. They have the same general properties and staple as the preceding, becoming more and more inferior, however, in the order of the list given. Gossypium hirsutum. White Egyptian, unlike the brown variety described above, is not indigenous, but was transplanted from America. In length of staple it varies from ij to if inches, with a mean of ij inches; the diameter averages 0.00077 mcn - This cotton shows a large number of fibres having but partially developed spiral twists. Orleans cotton is the typical American variety, and is perhaps the best of the American cottons.* The from cultivation, as its quality has greatly deteriorated. Egyptian cotton, as a class, is not so fine as sea-island, but is better than American upland cotton, that is, for goods requiring a smooth finish and a high lustre, the staple being strong and silky. * In the United States only the herbaceous cottons are cultivated to any extent; the shrubby and arboreous are occasionally grown as curiosities, but they sel- 184 THE TEXTILE FIBRES. fibres are quite uniform in length, having an average staple of about i inch and a mean diameter of 0.00076 inch. It is almost pure white in color. Texas cotton much resembles the fore- going, but has a slight golden color; its length and diameter of staple are the same. Upland cotton * is another very similar variety; its length of staple, however, is somewhat less than the foregoing, averaging but if inch. Its twist is rather inferior to the Orleans, and it shows a larger number of straight fibres. Mobile cotton is the most inferior of the American varieties; it varies in length of staple from f to i inch, with a mean of j inch; its aver- age diameter is 0.00076 inch. It shows about the same micro- scopic appearance as upland cotton. Santos cotton comes from Brazil; it is not much in demand on account of its inferior quality. f Gossypium peruvianum. Rough Peruvian; this cotton has a light creamy color and is rather harsh and hairy in feel.f In length of staple it varies from ij to i-& inches, with a mean of ij inches; its mean diameter is about 0.00078 inch. Most of the fibres dom or never produce any lint in regions having as low a mean temperature as the American cotton belt. (Bulletin No. 33, U. S. Dept. Agric.) * There are more than a hundred recognized horticultural varieties of upland cotton in cultivation, all belonging to one botanical species G. hirsutum, native to the American tropics. The original wild plants in the tropical zone were perennials, but the plant is cultivated as an annual. (Yearbook, U. S. Dept. Agric., 1903.) t The variety known as G. braziliense is a representative of the so-called "kidney cottons." In these cottons the seeds of each cell are closely adherent in an oval mass, whereas in the other varieties of cotton the seeds are free from each other. G. braziliense is an arborescent plant with very large 5 to 7 divari- cate-lobed leaves and very deeply laciniate involucral bracts. The Brazilian cottons appearing in trade under the names Santos, Ceara, Pernambuco, etc., do not seem to belong to G. braziliense, as they are not kidney cottons; they evi- dently belong to the G. barbadense and G. herbaceum species. J Peruvian cotton is often called kidney cotton, being characterized by the seeds in each lobe of the capsule clinging together in a compact cluster. These seeds are black and without a persistent fuzzy covering. The lint shows a wide variation in color and texture white, brown, reddish, rough and harsh, or smooth and soft. Most of it has a shorter, coarser, and more wiry fibre than that of American upland. The lint of some varieties is much like wool in appearance It is imported chiefly for mixing with wool or for producing special effects. Kid- ney cotton is found in Central America and also in the Philippines and other tropical islands of the Pacific, but it is not cultivated in commercial quantities outside of South America. (Yearbook, U. S. Dept. Agric., 1903.) COTTON. 185 are only partially twisted. Smooth Peruvian has a soft, smooth feel, but the staple is not so strong as the preceding. The length is about the same as the foregoing, as is also the diameter. Per- nambuco has a slight golden color and feels harsh and wiry. It is a variety of Brazilian cotton. It is rather regular in length of staple, the mean being i J inches. The diameter averages 0.00079 inch. Under the microscope the twists appear regular and well denned. Maranhams cotton is very similar to the preceding in microscopic appearance and length and diameter of staple. Ceara is a Brazilian cotton, rather inferior to the others by reason of its considerable variation in length of staple. Maceo is a similar variety, but somewhat harsher. West Indian cottons nearly all belong to the peruvianum species; they are usually long in staple and harsh and wiry in feel, and only of moderate strength. The length is quite uniform and averages i J inches. The diameter varies considerably, but has an average of about 0.00077 inch. The twist is short and very uniform, surpassing even sea-island in this respect. Chinese cotton, also known as Nankin cotton, is classified as G. religiosum; it yields a naturally colored fibre, being rather dark yellowish brown. It grows principally in China and Siam. CHAPTER X. THE PHYSICAL STRUCTURE AND PROPERTIES OF COTTON. i. Physical Structure. Physically the individual cotton fibre consists of a single long cell, with one end attached directly to the surface of the seed. While growing the fibre is round and cylin- drical, having a central canal running through it; but, after the enclosing pod has burst, the cells collapse and form a flat ribbon- like fibre, which shows somewhat thickened edges under the microscope. The juices in the inner tube, on the ripening of the fibre, are drawn back into the plant, or dry up on exposure to light and air, and in so doing cause the fibre to become twisted into the form of an irregular spiral or screw-like band, by reason of the unequal collapse and contraction of the cell- wall.* Fibres that have not ripened differ somewhat in these characteristics, being straight and having the inner canal stopped-up, in conse- quence of which they do not spin well and are difficult to dye, showing up as white specks in the finished goods; this is known as dead cotton.-\ The presence of an inner canal in the cotton fibre no doubt adds to its absorptive power for liquids, and its capillary action allows cotton to retain salts, dyestuffs, etc., with considerable power; but too much importance in this respect must not be attributed to the canal, for when cotton is mercerized the canal is almost entirely obliterated by the walls being squeezed * The number of twists in the cotton fibre in the raw state is said to be from 300 to 500 per inch. t The presence of "dead cotton" is very objectionable, as the fibre is weak and brittle, and consequently reduces the strength and durability of the yarn into which it may go. There is a considerable amount of unripe or partly ripened bolls always to be found in cotton-fields, and the fibres from these consist almost exclusively of "dead cotton." The proper utilization of, such cotton is a serious question, for the fibre is too weak to be used for spinning, and the cost of gather- ing and ginning makes the fibre too expensive for most other purposes, such as for absorbent cotton, cotton batting, or material for guncotton. 1 86 PHYSICAL STRUCTURE AND PROPERTIES OF COTTON. 187 together (see Fig. 54), and yet mercerized cotton is mu'ch more absorptive of dyes, etc., than ordinary cotton. The capillarity FIG. 54. Cross-sections of Mercerized Cotton Fibres, showing the Appearance of the Inner Canal. of the cotton fibre is no doubt principally due to the existence of minute pores which run from the surface inward. The crystal- lization of salts in these pores and in the central canal may lead to the rupturing of the fibre, as, for instance, when filter-paper is made by disintegrating cotton fibres by saturating them with water and then freezing them. The following table of the length and diameter of different Name of Cotton. Length in mm. Diameter in fi. Name of Cotton. Length in mm. Diameter in ft. Sea-island 41.9 46 6 9- 6 5 West Indian A. mcrican * 3 2 -3 19.6 20 o 3Q o Orleans . 27 O IO 2 Tohn Isle ?Q ? Upland . . 2Q ^ IO 4 Florida OV -O 4.c 7 16.18 Texas 24. 3 16.6 Fitschi 48 7 16 7 Mobile 2C O IO 4 Tahiti . A.2 Q 16 ^ Georgia 2< 4 IO. ^ Peruvian 38 o I r ? Mississippi. . . . 24. 2 7.4 Egyptian 22 I 16 7 Louisiana 2C .O Gallini 37 2 17 I Tennessee 2S . I 1C .O 18 7 A jrican 27 6 20 8 White JT 8 Indian IQ ^ Smyrna 6 L - 28 q 22.8 Hingunghat 28.3 20. o Brazilian 18.8 Dhollerah 28.2 21.5 Maranham Pernambuco Surinam 28.8 35- 2 2Q 2 20.4 20. o Broach Tinnevelly. -,.... Dharwar 20.9 23.0 23.6 21.8 21 .O 21 .O Paraiba . 2Q 7 Oomrawuttee. . . 24. I 21.5 Ceara 28 I 20 o Comptah 23.8 21.5 Maceo 20 3 Madras 21.8 21.8 Peruvian Tough 2Q O 21 C Scinde 20. 4 21 . 3 7Q O 21 C Bengal. . 2? . 7 23.7 Agerian 77 c Chinese 21.4 24. I ' i88 THE TEXTILE FIBRES. varieties of cotton fibres has been collated as a mean of several observers. The cotton fibre is rather even in its diameter for the greater part of its length, though it gradually tapers to a point at its out- growing end. The different varieties of cotton show consider- able variation, both in length and diameter of fibre; in sea-island cotton the length is nearly 2 inches, while in Indian varieties it is often less than i inch.* The diameter varies from 0.00046 to o.ooi inch; the longest fibres having the least diameter. Evan Leigh (Science of Modern Cotton Spinning) gives the following summary of the length and diameter of cotton fibres: Place of Growth. Kind of Cotton. Length in Inches. Diameter in Inches. Min. 0.88 1.41 1.03 1.30 0.77 -95 1.36 Max. Mean. Min. Max. Mean. United States. . Sea-islands. . . . South America. EffVDt New Orleans. . . Long stapled. . . Brazilian .16 .80 31 52 .02 . 21 65 I .02 1.61 1.17 1.41 0.89 i. 08 J-S . 0005 80 . 000460 .000620 .000590 . 000649 .000654 .000506 .000970 000820 .000960 .000720 . 000040 . 000996 . 000864 .000775 . 000640 .000790 .000655 . 000844. .000825 .000730 EsvDtian. . India \ I Native American seed. Sea-island seed. * Bulletin No. jj (U. S. Dept. Agric.) gives the following table compiled from numerous measurements taken during a period of years, showing the maxi- mum, minimum, and average length of fibre for some of the most important varieties of cotton, as well as the average diameter of the same: Variety. Length in Inches. Diameter, Inches. Max. Min. Aver. Sea-island .80 .16 . 12 .06 5 2 3 1 .02 .21 65 1.41 0.88 0.87 0.81 1.30 1.03 0.97 -95 1.36 1.61 I .02 I .00 o-93 1.41 1.17 0.89 i. 08 1.50 . 000640 .000775 .000763 .000763 .000655 .000790 . 000844 . 000825 .000730 New Orleans Texas Upland Egyptian Brazilian Indian varieties: Native American seed Sea-island seed From these measurements it will be observed that, as a rule, the longer the fibre the less is its diameter. The extreme variations in the above measurements of length is from 0.25 to 0.30 inch. In proportion to the size of the fibre, the variation in diameter is much greater than that for the length. PHYSICAL STRUCTURE AND PROPERTIES OF COTTON. 189 Hannan gives the following varieties and qualities of cotton to be met with in commerce. Types. Variety. L'gth, Ins. Diam- eter, Ins. Counts. Use. Properties. Sea-island. . Edisto. ..... 2.20 . 00063 300-400 Warp Long, fine silky, or weft and of uniform diameter Florida 1.8 5 . 00063 150-300 do. Shorter, but similar to above Fiii . I 75 . 0006"? I OO 2 5 O do. Less uniform in * / j length, but silky and cohesive Tahiti 1. 80 . 00063 c c do. Good, fine and glossy staple Egyptian. . . Brown J-S . 00070 i2O-down do. Long, strong, high- ly endochromatic Gallini 1. 60 . 00066 250-down Warp High-class staple of nd strength Menouffieh. . 1-5 < 2Oo-down Weft cj ood staple and lustre Mitafifi. . . . J - 2 5 < < IOO Warp Fairly good staple or weft White i .00 .00078 70 do. Pearly white, good long staple Peruvian. . . Rough 1-25 .00078 50-70 Warp Strong, woolly, and harsh staple Smooth 1 .CO < t 1 1 Weft Less woolly, and softer staple Red I . 2? < < 40-50 Warp Color weaker and *T V tr harsher t han brown Egyptian Brazilian. . . Pernambuco. !-5 .00079 50-70 Warp Strong and wiry Maranham. . I - I 5 < 50-60 do. Harsh and wiry Ceara i . 15 60 Weft Good, white, and x j cohesive staple Paraiba I . 20 < 50-60 Warp Fairly strong, harsh, or weft of good color Rio Grande. I - I S t 40-50 Weft Soft, white, and hars"h staple Maceio 1.20 . 00084 40-60 Warp Soft, pliable, and or weft good for hosiery Santos 1.30 < 50-60 Weft Exotic from Ameri- can seed, white and silky staple Bahia 40-50 Warp Fairly strong, but or weft harsh and wiry American. . . Orleans I. I .00077 34-4 do. Medium length, pearly, white Texas I -5 < t 32-40 do. Similar to above, rather harsher and more glossy Allanseed. . . 1.20 < t 50-60 Warp Good, white, long; blends with brown Egyptian Mobile I .00 .00076 40-50 Warp or weft Even-running sta- ple, soft and cohe- sive 190 THE TEXTILE FIBRES. Types. Variety. L'gth, Ins. Diam- eter. Ins. Counts. Use. Properties. American. . . Norfolks. . . . St. Louis. . . . Ronoaks. . . . Boweds I .00 0.90 0.90 00076 < i 1 1 40-50 3-3 2 30-34 36 Weft Warp do. Weft Used for Oldham counts of 50*3 Staple irregular, glossy, but short A white and strong staple Similar to uplands Benders. . . . Memphis. . . Peelers Uplands. . . . Alabama. . . . Linters . . I . 10 I .00 i- 2 5 I .00 0.90 .00077 < < 60 40-50 60-80 36-40 26-30 8-10 Warp do. Weft do. Warp or weft Weft Strong, creamy or white, for Turkey- red dyes Bluish white, for ex- tra hard twists Long, silky, fine staple; adapted for velvets, etc. Glossy when clean, apt to be dull, sandy, and leafy Short staple, of less strength, varying color Short - stapled gin Creek Tennessee. . Smyrna 0.90 I 2< < i 28 36 40 Warp or weft Warp waste Of varying length and color Harsh and strong, African . . . Lagos. . o 80 2026 Weft adapted for double yarns Dull and oil-stained West Indian Carthagena. I ^O 26 Warp irregular in length and strength From exotic seeds; China . ... La Guayran. China I .20 I OO 40 20 Warp or weft Weft fairly strong Irregular and short, but silky staple Harsh short, and Australian. . East Indian Queensland. Oomrawuttee Hingunghat . Comptah. . . !7-5 I .00 I .00 I O^ .00066 . 00083 < i 20 200 26-32 28-36 Warp or weft Warp Weft Warp white Long, white, silky, fine diameter Short, strong, and white Best white Indian staple Generally dull and Broach. . . . Dharwar. . . Assam 0.90 I .00 0.50 28-36 28 15-20 or weft Weft Warp Warp charged with leaf Like Hingunghat, gives good white weft Exotic from Ameri- can seeds White, but harsh, to blend with other cottons PHYSICAL STRUCTURE AND PROPERTIES OF COTTON, 191 Types. Variety. L'gth' Ins. Diam- eter, Ins. Counts. Use. Properties. East Indian Bengals 0.80 20-30 Warp Dull and generally or weft charged with leaf Bilatu O. CO 10 20 do. W^eak brittle and w coarse Dhollerah. . . o. 70 15-20 do. Strong, dull, and co- hesive Surat 0.60 10-15 do. Dull and leafy, often stained Scinde 0.50 to 10 do. Very strong, dull, short, and poor staple Tinnevelly. . 0.80 24-30 do. Lustrous white, soft, and adapted for hosiery Bhownuggar I. 00 28-30 Warp White when clean; often leafy and dirty Cocoanada. O 7O 1014 Brown Brown rirul dull" w . ^w weft used as quasi- Egyptian Bourbon. . . . I.OC 30 Weft Exotic; of good sta- ple; scarce Khandeish. . o.8c . 00083 20-26 Warp Similar in class to or weft Bengal Madras or O. 7C 1C 20 do. Used for low yarns Westerns. . / "O in coarse towelling, etc. Rangoon. . . . o.6c to 10 Warp Weak, dull, often or weft stained and leafy Kurrachee. . o oo 28 do. Fairly strong dull w - y^ and leafy Italian , Calabria. . . . o.oo 26-28 do. Fairly strong, irreg- ** y^ ular and dull,leafy Turkey Levant 1.25 .00077 36-40 Warp Harsh, strong, and white Monie (The Cotton Fibre) gives the following tables descriptive of the principal commercial varieties of cotton.* As the de- scriptions given in these tables vary, in some respects, quite con- siderably from the preceding tables of Hannan, it is probably best that both should be given: * Monie remarks in connection with this table that it will be observed that the Fiji and Tahiti sea-island cottons are the most irregular in the length of their fibres, the extreme variation in both being half an inch. As long and short cotton never incorporate well together nor adapt themselves to the production of a regular yarn in appearance and strength, it is easy to understand that they are relatively wasteful cottons to work. In any spinning mill where they are used, it will be found that the quantity of "fly," "combings," and "flat waste" made at the various machines is very great, and the reason of this is that in any cotton where the fibres are of different lengths, the long and strong will have a tendency to throw out the short and weak. The cotton which presents the great- est regularity is the Orleans. In comparing the diameters of various cottons with their lengths, it will be found that the longest cottons are usually the finest. 192 TEXTILE FIBRES. Characteristics . mgth and small diameter; silkiness; free from impuiiiies; contains some short and undeveloped fibre o' 4 milar to preceding, but weaker and contain- ing larger percentage of unripe fibre f a light golden color, very strong and much easier to work into yarn than sea-island ot so fine or silky as sea-island proper; of a light golden tint ; fibre moderately strong; apt to contain much dirt Is rf M -o c i| !i If si s fta o 1 d TO cf d "u "w 8 c ll 1 i 43 2 c/3 ^ 'S M ^u II s s TO S| TO - >ft, smooth, and pliable; resembles Orlears in color, and in other respects the "rough" variety h-1 CO % CO O O CO llf 4 4 6 6 e g: * h slfe H H jLj c3 ^ 8 f 00 150200 150-200 o I t**. o IOO-I3O o m t i . in ^ ^ m in M 00 M ON ll! f f f . CO 00 I Q o 1 " 1 O o' o O O d d , w rt -<8 m H ^ ^ M M x 6'C o 1 ^ CO CO CO CO CO CO W >'^J d d d o d d c 8 ^ m ^ CO VO H oo 00 8 ^1 00 vO 00 I in M in " M *j .s| in M o * in CO m H M o" in in in 5 L ^t ^ . S hS cs M N M H M M W M 1 ri d . . cs | d d rt TO d ^^ d TO P-4 *> .2 O J 8 .52 PL, b i 2 bo O n . p H ""T 4 c ai CO r*1 PH rH S 4n rt TO '3 .2 d J5 c3 "7 *C CO 3 ^S B bO 3 8 Jro QJ cd 2 g CO S g 1 O H m 00 PHYSICAL STRUCTURE AND PROPERTIES OF COTTON. 193 h en | >-d en CJ f a ' cu C CD &0 cu tn 8 Iff o cu "tn -3 >> 83 3 2 ^<^ "c c 82 o en bC || U st (_ en ^ d li tl - C a " II gS M-a SjT sl .2 rt ss Of a dull golden tint; fibres not so strong Pernambuco; sometimes quite dirty 1 oT 1 g 8 I 1 Finest of American white cottons; genera clean; economical to work; fibres soft ai moist and of fair strength Of a light golden tint; other characteristi similar to Orleans Similar to Orleans, but somewhat weaker Never so clean as either Upland or Orlearj and not quite so strong Color a dull white; fairly clean; of mediu strength 1 b o -o lj t- O ifl .2 S 6' S 8-t C ^s 2"^"* ^ ctf >*v* *** t/T o ||| 'O 'w 3 ifi 5 Of a. light golden tint; fibres strong, of ten rath dirty; the fines varieties of Indian cotton # H I 4 8 4 ^ i -8 EH' ^ H H h i f I o 1 o 1 o 1 o 5- B \o *J # 00 00* ^ VO 5 o 5 vO 5 # ^ ON M % d 6 1 O o o o o o o' O* 6 IO 10 10 CM ON 10 10 IO M H H CM CO > l/l 1 s| s ^ be tn f3 1 ^ I 1 Exceedin deeper strong |^ '3 t rt y rt H p !l S" - > > > 1 # <8 ^ 4 4 ^ H ^ ^ ^ o II "I t H H h z ^S s 1 o CM 8 o H 2 & C 2 1 2 2 2 2 r ro VO ^ x *. ^ 3 < O hH d d d d CO d d d d x M i III ft ^ ? PJ E | 2 H < o E X 3 %T 5K) 1 K/ it rr I2O 66 ^. ^ 24 2 CQ I2O 68 T C. 22 T/13'S " " 4O 2? 6 165*3 Sea-island cotton igo's " " 45 38 IOO IOO 55 55 ^6 3 IO C J- u 25-4 4J iu. 5 PHYSICAL STRUCTURE AND PROPERTIES OF COTTON. 207 the various processes of spinning and finishing. It also has an influence on the commercial valuation of the raw material, as the amount of hygroscopic moisture varies with atmospheric condi- tions, and it is important to have a normal standard of reference (see Conditioning of Wool, chapter iii).* Its influence on spinning FIG. 60. Appearance of Cotton Fibre en Treatment with Schweitzer's Reagent. (After Witt.) a, transverse ligatures of disrupted cuticle; , irregular shreds of cuticle torn apart; <:, swollen mass of cellulose; d, walls of internal canal. is even greater, and proper conditions of atmospheric moisture must be maintained in the spinning-room in order to achieve the best results; the spinning properties of raw cotton, however, are also affected by other substances associated with the cellulose of the fibre, but it is without question that the physical condi- tion of cotton is largely influenced by its content of hygroscopic moisture, and this should be delicately adjusted by the spinner to meet the conditions of his work. The mechanical treatment * The amount of "regain" allowed in the conditioning of cotton on the con- tinent of Europe is 8 per cent. 208 THE TEXTILE FIBRES. of woven textile materials in finishing processes, such as mangling, beetling, calendering, etc., is also dependent for good results to quite an extent on the hygroscopic condition of the fibre; the amount of moisture present during the finishing operations, together with the method and degree of drying, should be care- fully studied.* FIG. 61. Cotton Fibre. A, middle portions of fibre; B t points or ends of fibre. When cotton is purified from its adhering waxy and fatty matters, it becomes remarkably absorbent. This quality is explained on the supposition that the ripe cotton fibre is made up of a series of tissues of cellulose, separated from each other by intercellular matter, in this way forming a series of capillary surfaces which are capable of exerting considerable capillary force upon any liquid in which the fibre may be immersed. Dry cotton also appears to be remarkably absorptive of gases; it is said that the fibre can absorb 115 times its volume of ammonia at the ordinary atmospheric pressure. * In testing the influence of moisture on the strength of cotton material, the Industrial Society at Mulhouse reports as follows: Normal strength of cloth 100 Saturated with moisture 104 Dried on hot cylinder 86 Again dampened 103 It would appear from these results that the alternate moistening and hot drying of cotton caused little or no deterioration in its strength. CHAPTER XI. r CHEMICAL PROPERTIES OF COTTON; CELLULOSE. i. Chemical Constitution. In its chemical composition cot- ton, in common with the other vegetable fibres, consists essentially of cellulose. On the surface there is a protecting layer of more or less wax and oily matter, and also in the fibre there is a trace of pigment, which in some varieties of cotton becomes quite emphasized. The removal of these substances is the object of the boiling-out and bleaching process to which cotton is sub- jected prior to its dyeing and printing. In reality the purified cotton fibre as it exists in bleached material is practically pure cellulose, and this compound alone appears to be essential to its structural organization. The natural impurities present in the raw cotton fibre amount to about 4 to 5 per cent., and consist chiefly of pectic acid, color- ing-matter, cotton- wax, cotton-oil, and albuminous matter. The fibre gives about i per cent, of ash on ignition.* The oil present in the fibre appears to be identical with cottonseed-oil, and is probably obtained from the seed to which the fibre is attached. The cotton-wax serves as a protective coating for the fibre and makes it water-repellent, as is evidenced by the long time it requires for raw cotton to be wetted out by simply steeping in water. This wax appears to be closely analogous to carnauba wax; it is not soluble in alkalies, though it may be gradually emul- sified by a long-continued boiling in alkaline solutions, on which * Bowman is of the opinion that considerable stress should be laid on the fact that the cotton fibre contains about i per cent, of mineral matter as an integral part of its constitution, and this no doubt has considerable influence on its struc- ture and properties. 209 2io THE TEXTILE FIBRES. fact is'based the " boiling- out " of cotton by the ordinary methods. Cotton- wax, however, appears to be readily soluble in sulphated oils, such as Turkey-red oil, and hence cotton may be rapidly and thoroughly wetted out by using a solution of such an oil. The coating of wax over the cotton fibre appears to influence its spinning qualities to a certain extent, as it requires, for instance, a rather elevated temperature to successfully spin fine yarns, in order probably to soften the waxy coating of the fibre.* The fatty acid present in cotton-wax has been found to be identical with margaric acid. According to Dr. Schunck, American cotton contains about 0.84 per cent, of fatty matters, whereas East Indian cotton contains only 0.337 P er cent - Analysis of cotton- wax shows it to consist of the following: Per Cent. Carbon 80 . 38 Hydrogen 14.51 Oxygen 5.11 It fuses at 85.9 C., and solidifies at 82 C., hence it bears a close analogy to both cerosin, or sugar-cane wax, and carnaliba wax. The coloring-matter of cotton has been investigated and has been found to consist of two organic pigments, the one easily soluble in alcohol and the other dissolved only by boiling alcohol. According to Schunck, the composition of these bodies from Nankin cotton is as follows: A. Soluble in B. Insoluble in Cold Alcohol , Cold Alcohol, Per Cent. Per Cent. Carbon 58.22 57-7 Hydrogen 5-42 5 . 60 Nitrogen 3.73 4.99 Oxygen 32 . 63 31.71 * As the temperature falls the oily wax tends to become stiff and gummy, and prevents the proper drawing of the fibre; while its presence among the thin laminations of the cell-walls gives a greater elasticity to the fibre, and renders it less liable to sudden rupture. The gradual drying-up of the more volatile portions of this oil in the fibre, leaving the remaining portion thicker and stiff er, may also, and probably does, account for the fact, noticed by most spinners, that new-crop cotton seems to work better and makes less waste than cotton harvested as ihe season advances. (Bowman, Cotton Fibre, p. 55.) CHEMICAL PROPERTIES OF COTTON ; CELLULOSE. 211 The composition of the analogous coloring-matters in American cotton is practically identical with the above. Pectin compounds form the greater portion of the impurities present in cotton, and are probably rather complex in nature. The quantity of ash (mineral matter) in raw bale-cotton will average considerably higher than that obtained from the purified fibre; this is due to adhering sand and dust which are nearly always present. The following table shows the amount cf ash contained in samples of different varieties of cotton : * Per Cent. Dharwar 4.16 Dhollerah 6.22 Sea-island 1.25 Peruvian (soft) i . 6S " (rough) 1.15 Bengal 3 . 98 Broach 3.14 Oomrawuttee 2.52 Egyptian (brown) i . 73 " (white) 1.19 Pernambuco i . 60 American 1.52 When the amount of ash is found to be over i per cent., the excess may be considered as mechanically attached sand and dust. The true ash of the cotton fibre consists principally of the carbonates, phosphates,f chlorides, and sulphates of potassium, * Monie (The Cotton Fibre} gives a table showing the percentage of sand or mineral matter contained in bales of commercial cotton as they arrive at Liverpool. Sea-island Rough Peruvian.. Gallini Egyptian, Brown Egyptian. Orleans ,10 Upland 2.10 ,25 Bahia 2.16 .25 Hingunghat 2.33 .60 Broach 2.58 60 Oomrawuttee ... 2.93 . 75 African 3.2 White Egyptian Smooth Peruvian i .80 Dhollerah 4. 10 Pernambuco 1.98 Comptah 4. 18 Texas 2.10 Bengal, 5.3 It is to be presumed that Monie did not include in the above figures the amount of mineral matter in cotton as obtained from the ash of the purified fibre, but that his figures represent the sand or other foreign mineral matter mechanically held in the baled cotton. f According to Calvert (Jour, prakt. Chem 1869, p. 122), cotton samples 212 THE TEXTILE FIBRES. calcium, and magnesium, as is exhibited by the following analysis of Dr. Ure: Per Cent. Potassium carbonate 44 . 80 ' ' chloride 9 . 90 ' ' sulphate 9-3 Calcium phosphate 9 . oo ' ' carbonate 10 . 60 Magnesium phosphate 8 . 40 Ferric oxide 3 . oo Alumina and loss 5 . oo The analyses of Davis, Dreyfus, and Holland, reported as a mean from twelve different varieties of cotton, show a little difference from the above analysis, especially in having present sodium carbonate as one of the constituents. The mean of these analyses is given as follows: Per Cent. Potassium carbonate 33-22 ' ' chloride 10.21 ' ' sulphate 13 . 02 Sodium carbonate 3 . 35 Magnesium phosphate 8.73 * ' carbonate 7.81 Calcium carbonate 20 . 26 Ferric oxide 3 . 40 The albuminous or nitrogenous matter present in cotton is only of very small amount, and doubtless consists of protoplas- mic residue. Different varieties of cotton, on analysis, show the following percentages of nitrogen; some of this, however, may be derived from mineral nitrates which may be present in slight amount in the fibre (Bowman) : Per Cent Nitrogen. American o . 030 Sea-island o . 034 Bengal o . 039 Rough Peruvian o . 033 Egyptian (white) o . 029 ' ' (brown) o . 042 Mean. 345 from different countries contain the following percentages of phosphoric acid soluble in water: Egypt -5S Surat 0.027 New Orleans. . . . 0.049 Carthagena. . . . 0.035 to 0-050 Bengal 0.055 Cyprus... 0.050 CHEMICAL PROPERTIES OF COTTON ; CELLULOSE. 213 Analyses conducted by the U. S. Department of Agriculture give the average amount of nitrogen present in cotton as 0.34 per cent. As this differs very considerably from that obtained by Bowman, it may be possible that the values of the latter must be multiplied by ten to obtain the correct figure. Church and Miiller have made careful analyses of raw cotton with the following results: * i. ii. Cellulose 9 I - I 5 9 x -35 Hygroscopic water 7 . 56 7 . oo Wax and fat o-S 1 0.40 Nitrogen (protoplasm) 0.67 0.50 Cuticular tissue o. 75 Ash o . 1 1 o . 1 2 2. Cellulose. This is one of the most important of the natu- rally occurring chemical compounds, as it forms the basis of all vegetable tissue. Chemically it consists of carbon, hydrogen, and oxygen, and has the empirical formula C 6 H 10 O 5 .t It belongs * Bulletin No. jj (U. S. Dept. Agric.) gives the following analysis of the cot- ton fibre, representing the average of a number of tests: FERTILIZING CONSTITUENTS. Per Cent. Water 6. 07 Ash 1.37 Nitrogen o . 34 Phosphoric acid o. 10 Potash o . 46 Soda o . 09 Lime 0.19 Magnesia o . 08 Ferric oxide 0.02 Sulphuric acid 0.6 Chlorin o . 07 Insoluble matter 0-05 PROXIMATE CONSTITUENTS. Water 6. 74 Ash i . 65 Protein i . 50 Fibre (cellulose) 83.71 Nitrogen-free extract 5 . 79 Fat 0.61 t The cellulose of all vegetable tissues, even in a highly purified condition, appears to contain a small amount of mineral constituents, apparently forming 214 THE TEXTILE FIBRES. to a class of bodies known as carbohydrates, and is closely related to the starches,* dextrins, and sugars. Chemically considered, these compounds must all be regarded as alcohols containing aldehydic and ketonic groups. The word " cellulose " must not be taken as signifying a simple definite substance of unvarying properties, but rather as a generic term including quite a number of bodies of similar chemical nature. Like starch and other complex carbohydrates of organic physical structure, cellulose will vary somewhat in its properties, depending upon its source or derivation. As a class the celluloses exhibit certain chemical characteristics, by means of which they may be distinguished from associated bodies of allied chemical constitution. Physically they are colorless amorphous substances capable of withstanding rather high temperatures without decomposition. They are insoluble in nearly all of the usual solvents, but dissolve more or less completely in an ammoniacal solution of copper oxide (Schweitzer's reagent). f Solution in this latter reagent appparently an integral or organic portion of the fibre structure. The amount of ash, for instance, obtained from bleached cotton is about o.i to 0.4 per cent. Even "Swedish" filter-paper, which has been treated with hydrochloric and hydrofluoric acids for the removal of inorganic constituents, will still contain from 0.03 to 0.05 per cent, of ash. * Though cellulose appears to be somewhat analogous to these bodies, it never- theless differs from them in its much greater resistance to the hydrolytic action of acids, alkalies, and enzymes. The latter reagents readily split up the starches into simpler bodies; but no such reaction, through artificial means at least, has been observed in the case of cellulose. That such a reaction, however, takes place in the tissues of the growing plant there is no doubt. t Cross and Bevan make the following remarks respecting this reagent: The solutions of cuprammonium compounds generally, in the presence of excess of ammonia, attack cellulose rapidly in the cold, forming a series of gelatinous hydrates, passing ultimately into fully soluble forms. The solutions of the pure cuprammonium hydroxide are more active in producing these effects than the solutions resulting from the decomposition of a copper salt with excess of ammonia. Two methods are in common use for the preparation of these solutions, which should contain 10 to 15 per cent, of ammonia and 2 to 2.5 per cent, of copper as the oxide, (i) Hydrated copper oxide is prepared by precipitating a solu- tion of copper sulphate of 2 per cent, strength with a slight excess of a dilute solu- tion of sodium hydrate. The precipitate is washed until it is entirely free from alkali. The original solution in which the solution takes place, as well as the water used in washing, should contain a small quantity of glycerol. The washed precipitate is well drained, and then mixed with a quantity of a 10 per cent, solu- CHEMICAL PROPERTIES OF COTTON; CELLULOSE. 215 takes place without decomposition, as the cellulose may be repre- cipitated unchanged therefrom by the addition of acids and various salts. In order to obtain pure cellulose for chemical purposes, it is customary to treat cotton successively with dilute caustic alkali, dilute acid, water, alcohol, and ether.* The re- sult of this treatment is to remove all foreign and encrusting materials from the raw fibre, and possibly also to remove the thin, external cuticular membrane which may be chemically different from the rest of the tissue. The specific gravity or density of cellulose as obtained in the usual manner is about 1.5, and this also represents the density of cotton and most other plant fibres. Chemically considered, cellulose is a derivative of the open-chain or paraffin series of hydrocarbons, and further- more it exhibits the reactions of a saturated compound. As with the other carbohydrates, chemists have found it a matter of great difficulty to ascertain even approximately the true mo- lecular formula of cellulose. Though its empirical formula is CfiHioOs, this in no way represents the true molecular complexity lion of glycerol, in contact with which it may be preserved unchanged in stoppered bottles. When desired for use, the oxide is washed free from glycerol and dis- solved in ammonia water (of 15 to 20 per cent strength). (2) Metallic copper, in the form of sheet or turnings, is placed in a cylinder and covered with strong ammonia; atmospheric air is caused to bubble through the column of liquid at a rate calculated to 40 times the volume of the liquid used per hour. In about six hours a liquid of the requisite composition is obtained. Solutions con_ taining 5 to 10 per cent, of cellulose are readily prepared by digestion in the cold with 10 to 20 times the weight of cuprammonium solution, a rather ropy or gelat- inous solution being obtained. The cellulose is readily precipitated from the solution: (a) by the addition of neutral dehydrating agents, such as alcohol, sodium chloride, and other salts of the alkalies, and (6) by the addition of acids, in which case the cellulose is precipitated in the pure state, or free from copper oxide. * Cross and Bevan recommend the following procedure in the isolation of pure cellulose in the study of the vegetable fibres : (a) The fibrous raw material is boiled with a dilute (i to 2 per cent.) solution of caustic soda, and, after thorough washing, is (&) exposed in the moist state to an atmosphere of chlorin gas; (c] it is again treated with boiling alkali. By such treatment the "non-cellulose" constituents of most vegetable fibres are removed, and a residue of pure cellulose is obtained. A subsequent slight treatment with a dilute solution of chloride of lime for the removal of traces of coloring-matters, and a final washing with alcohol and ether completes the purification. 2t6 THE TEXTILE FIBRES. of the substance.* From a study, however, of its various synthet- ical derivatives, with special reference to its esters, such as the acetates, benzoates, and nitrates, the provisional formula of Ci2H 2 oOio has been given to the cellulose molecule. The nature and position of the various organic groups present in this mo- lecular formula, however, have yet to be explained. f * There has been a considerable amount of speculation among chemists as to the chemical nature and constitution of cellulose, but there has been so little experimental data on which to frame an intelligent theory, that most of these speculations are mere scientific guesswork, and have little more than a pro- visional value. From the action of zinc chloride on cellulose it has been pre- sumed that the cellulose molecule contains hydroxyl groups of such a nature as to give it a salt-like property, and the solution of the cellulose in the zinc chloride is supposed to be due to the formation of a kind of double salt. There also appears to be a chemical reaction of limited degree between cellulose and dilute solutions of caustic alkalies and mineral acids. According to Mills, the relative molecular ratio of the absorption by cellulose of alkalies and acids is represented by ioNaOH:3HCl. From this and other considerations, it would appear that cellulose exhibits the properties of a feeble acid and of a still more feeble base. | Vignon has proposed to give cellulose the following constitutional formula: O CHv O ^>(CHOH) 3 . CH 2 CH/ This is based on a study of the highest nitrate of cellulose and the decomposi- tion of the nitrate by alkalies with formation of hydroxypyruvic acid. The struc- ture given, however, is more or less hypothetical in nature, and needs experimental confirmation in many particulars before it can be accepted without question The older chemical configuration of cellulose given by Bowman, H H H H C C=C=C C C H. II ill OH OH OH OH OH is without any experimental reason for its existence, and the idea that it contains an unsaturated carbon grouping, C=C , has been proved erroneous. From a study of the osazones of oxycellulose, Vignon has ascribed to this latter body the constitutional formula of the group, /COH (CHOH)/ X CH CO, O in union with varying proportions of residual cellulose. The existence of a compound containing cellulose and sulphuric acid in the CHEMICAL PROPERTIES OF COTTON; CELLULOSE. 217 In its chemical reactions cellulose is particularly inert, com- bining with only a few substances, and then only with great diffi- culty and under peculiar conditions. It is quite resistant to the processes of oxidation and reduction, and hydrolysis and dehy- dration.* Concentrated sulphuric acid dissolves cellulose with the production of a viscous solution; dilution with water causes the precipitation of an amorphous substance known as amyloid, a starch-like body having the formula C^H^On, and like starch it is colored blue with iodin. On this reaction is based the method of testing for cellulose, by applying sulphuric acid and iodin. On boiling with dilute sulphuric acid, cellulose is con- verted into dextrin and glucose. On heating with acetic anhy. dride to 180 C., cellulose is converted into an acetyl deriva- tive having the formula C^H^O^OCOCHs^.f By the mod- erated action of concentrated acids and various acid salts, cellulose appears to undergo a process of hydration, being converted into a friable amorphous body known as hydrocellulose or more properly hydrated cellulose.]. This reaction is of importance proportion 4C 6 H 10 O 6 to H 2 SO 4 is put forward as a proof that in its reactions cellu- lose behaves like a complex molecule of at least 24 carbon atoms. (See Cross, Bevan, and Briggs, Berichte, 1905, p. 1859.) * This high degree of resistance to hydrolysis (alkaline) and oxidation belongs only to cotton cellulose and to the group of which it is the type, and which includes the cellulose of flax, ramie, and hemp. A large number of celluloses, on the other hand, are distinguished by considerable reactivity, due to the presence of "free" carbonyl groups, and are therefore more or less easily hydrolyzed and oxidized. The celluloses of the cereal straws and esparto grass are of this type, and hence the relative inferiority of the papers into the composition of which they enter. (Cross and Bevan, Jour. Chem. Soc., 1894, p. 472.) f Cellulose does not react directly with acetic anhydride, but at the tempera- ture above given and with six times its weight of the anhydride it gives the deriv- ative having the above formula, and which may be called the triacetate. With a smaller quantity of acetic anhydride, a mixture of lower acetates is obtained which are insoluble in glacial acetic acid. The triacetate is readily soluble in this acid, however, and also in nitrobenzene. Its solutions are very viscous. Regenerated cellulose, prepared by precipitation of viscous solutions, reacts with acetic anhydride directly, and gives what appears to be the tetracetate. For further remarks concerning the acetylation of cellulose see Cross and Bevan, Cellulose and Researches on Cellulose. J The formula suggested for hydrocellulose is C^H^O,,. Sthamer (Ham- burg) prepares hydrocellulose by treating cotton (or other form of cellulose) 218 THE TEXTILE FIBRES. in the carbonizing process for removing vegetable matter from woolen goods. A concentrated solution of zinc chloride will dissolve cellulose on heating and digesting for some time.* This solution has been employed industrially for the preparation of cellulose filaments, which are subsequently treated with hydrochloric acid and washed for the purpose of removing the zinc salt; the thread is then carbonized and is employed for the carbon filament of incan- descent electric lamps, f A concentrated solution of zinc chloride in hydrochloric acid dissolves cellulose quite rapidly and hi the cold. J This latter method is useful in the laboratory for the study of celluloses, but as yet has received no technical application. By means of this solution it has been shown that the cellulose molecule does not contain any unsaturated carbon groups, for* it exhibits no absorption of bromin. A solution of a ligno- cellulose, on the other hand, gives a marked bromin absorption, thus showing evidence of unsaturated carbon groups. mixed with potassium chlorate with hydrochloric acid at a temperature of 6o-7o C. The product obtained in this manner is in the form of a white powder very resistant to acids and alkalies. * Cross and Bevan recommend the following method for preparing this solu- tion of cellulose: 4 to 6 parts of anhydrous zinc chloride are dissolved in 6 to 10 parts of water, and i part of bleached cotton is then stirred in until evenly mois- tened. The mixture is digested for a time at 60 to 80 C., when the cellulose is gelatinized; the solution is completed by heating on a water-bath and stirring from time to time, and replacing the water which evaporates. In this manner a homogeneous syrup is obtained. This solution of cellulose is entirely decom- posed by dilution, the cellulose being precipitated as a hydrate in combination with zinc oxide. On washing this precipitate with hydrochloric acid a pure cellulose hydrate is obtained, the quantity recovered being approximately equal to the original cellulose taken. When precipitated by the addition of alcohol, a compound of cellulose and zinc oxide is obtained, with 18 to 25 per cent, of ZnO, and having the approximate molecular ratio of 2C 6 Hi O 5 : ZnO. f The threads for the production of the carbon filaments are prepared by forcing the syrupy solution of cellulose through fine glass orifices into alcohol, whereby the cellulose is precipitated in a continuous thread. \ The reagent is prepared by dissolving one part of zinc chloride in twice its weight of concentrated hydrochloric acid. If the solution of cellulose obtained with this solvent is diluted when fresh, the cellulose will be precipitated unaltered; but if the solution is allowed to stand, the cellulose is rapidly resolved into decomposition products, such as dextrin, etc., which are entirely soluble in water. CHEMICAL PROPERTIES OF COTTON; CELLULOSE. 219 Cellulose is colored a deep violet by a solution of zinc chlor- iodide, and this reagent is employed as a delicate test for the presence of cellulose. The reagent may be best prepared by using 90 parts of a concentrated solution of zinc chloride, adding 6 parts of potassium iodide in 10 parts of water, and iodin until saturated. When cellulose is treated with concentrated caustic alkalies, it undergoes a change which may be crudely referred to as " mer- cerization," whereby a compound known as alkali- cellulose is formed, in which the molecular ratio of alkali to cellulose may be given as Ci2H 2 oOio:NaOH. When this body is treated with carbon disulphide, a substance known as cellulose thiocarbonate or xanthate is formed. This body yields a very viscous solution with water and has been utilized for various technical purposes (see vis- cose, chapter xiii).* Cellulose xanthate undergoes spontaneous decomposition, splitting up into cellulose hydrate, alkali, and car- bon disulphide; this cellulose hydrate is also known as regenerated cellulose, f This substance can also be precipitated by the * The best conditions for the preparation of viscose is to use the reagents in the following molecular proportions: C 6 H 10 O 5 :2NaOH:CS2 (with 30 to 40 H 2 O). The reaction is carried out in practice by treating bleached cotton (though other forms of cellulose, such as purified wood-pulp, may also be used) with ex- cess of a 15 per cent, solution of caustic soda, then squeezing out the excess of liquor, but leaving in the fibre about three times its weight of the solution. The mass is then mixed with about 50 per cent, (on the weight of the cotton) of carbon disulphide, and allowed to stand in a covered vessel for about three hours at the ordinary temperature; after which sufficient water is added to cover the mass, and the hydration allowed to proceed for several hours longer. The mass is then stirred up and a homogeneous solution is obtained which may be diluted to any desired degree. The solution thus prepared has a yellow color, which, however, is due to the presence of tri-thiocarbonates which occur as by-products in the reaction. By treating the solution with a saturated solution of common salt or with alcohol, pure cellulose thiocarbonate is precipitated as greenish white floc- culent mass, which may be redissolved in water, giving a colorless or faintly yellow- colored solution. On the addition of various metallic salts to this solution, the corresponding xanthates may be precipitated. With iodin a precipitate of dioxy-thiocarbonate is formed, which may be said to take place in accordance with the following equation: /OX X0\ /OX X0\ CS + CS + I 2 =2NaI + CS CS. \SNa NaS/ \S S/ f When this decomposition takes place in solutions containing more than one 220 THE TEXTILE FIBRES. addition of various salts, such as ammonium chloride. Alkali- cellulose also reacts with benzoyl chloride, with the formation of cellulose benzoate* Another ester of cellulose is the acetate, which can be made by the action of acetic anhydride on cellulose heated in a sealed tube f regenerated cellulose can also be employed. By varying the conditions of treatment a number of different acetates have been prepared.! The tetracetate has received a number of commercial applications for the production of films and for waterproofing. By the action of nitric acid under vary- ing conditions, a number of cellulose nitrates (improperly called nitrocelluloses) have been prepared, which have received numer- ous applications (see pyroxylin). Concentrated sulphuric acid reacts with cellulose to form at first a cellulose sulphate; this per cent, of cellulose, a firm jelly of coagulated cellulose is produced of the same volume as the original solution. A solution containing as much as 10 per cent, of cellulose decomposes to a substantial solid of hydrated cellulose which gives up its water with extreme slowness. The cellulose regenerated in this manner is probably in the "colloidal" form. * See Gross and Bevan, Cellulose, p. ' 32, and Researches on Cellulose, p. 34, etc. f According to a recent patent (Eng. Pat. 1905, No. 9998), an almost theoreti- cal yield of cellulose tetracetate may be obtained by conducting the acetylation in the presence of methyl sulphate; the process given being as follows: 30 parts of cotton are treated in a bath with 70 parts of acetic anhydride, 120 parts of glacial acetic acid, and 3 parts of dimethyl sulphate until solution is almost complete. The solution is then filtered and the filtrate is poured into a large quantity of water, whereupon the acetate of cellulose is precipitated. % The acetate of cellulose may be prepared by heating a mixture of hydrocel- lulose, acetic anhydride, and sulphuric acid to 6o-7o C. The acetate of cellulose so obtained is soluble in ether and chloroform (Lederer). At Sthamer's chemical works (Hamburg) acetate of cellulose is prepared by heating a mixture of hydrocellu- lose, acetic acid, acetyl chloride, and sulphuric acid to 65-7o C. An acetate of cellulose soluble in alcohol and pyridin is obtained by heating a mixture of cel- lulose, acetic anhydride, and sulphuric acid to 45 C. (Farbenfabriken vorms. Fr. Bayer & Co. of Elberfeld). Miles and Pierce (Brooklyn) obtain it by heating a mixture of cellulose, acetic anhydride, acetic acid, and sulphuric acid to 70 C. Landsberg substitutes phosphoric acid for sulphuric acid in the preceding mix- ture. Acetate of cellulose has also been prepared by warming a mixture of cellulose, acetic acid, acetic anhydride, and a mixture of phenol-sodium sulphonate and phenol -sulphonic acid, or of sodium naphtholate and naphthol-sulphonic acid (Little, Walker & Mork, Boston). Cellulose may also be acetylized by means of a mixture in nitrobenzene solution of acetyl chloride and chloride of zinc or magnesium, in the presence of pyridin or quinolin (Wohl, Charlottenburg). CHEMICAL PROPERTIES OF COTTON; CELLULOSE. 221 subsequently undergoes decomposition with a consequent hy- drolysis of the cellulose molecule and the formation of amy- loid. Aceto-sulphates of cellulose have been prepared by the joint action of acetic acid, acetic anhydride, and sulphuric acid on cellulose.* Although cellulose is comparatively inert to the majority of chemical reagents, it has a powerful attraction for certain salts held in solution and will absorb them completely. This power of absorption is especially marked towards salts of vanadium, these being completely separated from solutions containing only one part of the salt per trillion. Besides cellulose itself, there are a number of derived sub- stances which are known as compound celluloses. These are classified into three general groups: (a) Pectocelluloses, related to pectin compounds of vegetable tissues; represented among the fibres by raw flax; resolved by hydrolysis with alkalies into pectic acid and cellulose. (b) Lignocelluloses, forming the main constituent of woody tis- sue and represented among the fibres by jute; resolved by chlorina- tion into chlorinated derivatives of aromatic compounds soluble in alkalies and cellulose. (c) Adipocelluloses, forming the epidermis or cuticular tissue of fibres, leaves, etc. ; resolved by oxidation with nitric acid into derivatives similar to those of the oxidation of fats and cellulose. Fremy groups the various celluloses and their derived bodies in the following manner, which is based on a chemical classifica- tion: (a) celluloses, including normal cellulose, paracellulose, and metacellulose ; (b) vasculose (identical with lignocellulose) ; (c) cutose; (d) pectose. * See Cross, Bevan & Briggs, BericfUe, 1905, p. 1859. For the preparation of what these chemists term the normal cellulose aceto-sulphate, to which the formula 4(C 6 H 7 O 2 ) . (SO 4 ) . (C 2 H 3 O 2 ) 10 is ascribed, 16 grams of dry cotton are stirred for 20 minutes at 30 C. in 100 cc. of a mixture of equal parts of glacial acetic acid and acetic anhydride containing 4.5 per cent, by weight of sulphuric acid. After standing for one hour, a homogeneous, translucent, and viscous solu- tion is obtained, which is precipitated on being poured into water as a semi-trans- lucent, gelatinous hydrate, which is soluble in alcohol. By using less sulphuric .acid the product obtained is insoluble in alcohol. 222 THE TEXTILE FIBRES. 3. Chemical Reactions of Cotton. Cotton itself presents the same general reactions and chemical properties as cellulose. It is capable of standing rather high temperatures without decom- position or alteration; though it appears that when cotton is sub- jected to a temperature of 160 C., whether moist or dry heat, a dehydration of the cellulose takes place, accompanied by a structural disintegration of the fibre. This fact has an important bearing on the singeing, calendering, and other finishing processes where high temperatures are used. At 250 C. cotton begins to turn brown ; and when ignited in the air it burns freely, emitting an odor faintly suggesting acrolein, but without the characteristic- ally empyreumatic odor of burning animal fibres. When sub- jected to dry distillation cotton is decomposed into methane, ethane, water, methyl alcohol, acetone, acetic acid, carbon dioxide, pyrocatechol, etc. Though unaltered and insoluble in boiling water, when heated with water under pressure to 200 C. it is dissolved with complete decomposition. Like cellulose itself, cotton is dissolved by Schweitzer's reagent, though under ordinary conditions its solution is a rather slow process. In order to dissolve cotton most effectively in ammoni- acal copper oxide, it is recommended to treat the raw cotton with a strong solution of caustic soda until the fibres swell up and become translucent; squeeze out the excess of liquid, and wash the cotton with strong ammonia water; then treat with the solution of ammoniacal copper oxide and the cotton will be found to dissolve quite rapidly. This solution may furthermore be filtered and diluted with water. The use of this solution for the production of lustra-cellulose filaments has received some degree of com- mercial application (see Pauly silk, chapter xiii). This reaction is also utilized in the preparation of a fabric known as Willesden canvas; the cotton fabric is passed through a solution of am- moniacal copper oxide, whereby the surface becomes coated with a film of gelatinized cellulose containing a considerable amount of copper oxide. On subsequent hot pressing this film is fixed on the surface of the material as a substantial coating, which is said to make the canvas water-proof and render it unaffected by mildew and insects. CHEMICAL PROPERTIES OF COTTON; CELLULOSE. 223 Concentrated solutions of zinc chloride are capable of dis- solving cotton, but only after a prolonged digestion at about 100 C., though by first treating the cotton with caustic alkali the solution takes place in the cold. The product so obtained has received several industrial applications; vulcanized fibre is prepared by treating paper with a concentrated solution of zinc chloride,* and the resulting gelatinous mass is manufactured into various articles, such as blocks, sheets, etc. The chief difficulty encountered is the subsequent removal of the zinc salt, which necessitates a very lengthy process of washing. The ma- terial may be rendered water-proof by a further process of nitra- tion, f The solution has also been suggested for use as a thick- ening agent in calico-printing. Its use for the production of lustra-cellulose or artificial silk and incandescent-lamp filaments has also been attempted. With mineral acids cotton exhibits practically the same gen- eral reactions as pure cellulose. Concentrated sulphuric acid produces amyloid in the manner already mentioned, and this fact is utilized in the preparation of what is known as vegetable parchment. Unsized paper is rapidly passed through concentrated sulphuric acid, then thoroughly washed and dried. The effect of this treatment is to cause the formation on the surface of the paper of a layer of gelatinous amyloid, which on subsequent pressing and drying gives a tough membranous surface to the paper resembling true parchment. This renders the paper grease- proof and water-proof, and increases its tensile strength con- siderably. Artificial horse-hair has been prepared in a similar manner from certain Mexican grasses. These latter are steeped for a short time in concentrated sulphuric acid, and become parchmentized thereby, so thatiAi .being subsequently washed and combed they assume anj^^arance very much resembling horse-hair, and arc said to r^sess even greater elasiJMfr than * One part of paper is treated with four parts of zinc chlori to 75 Be. until the fibres are partially gelatinized, when the sheet! together into very compact masses. (See Hofmann, Handb. a^fapierfab., p. 170.) f Hofmann, ibid., p. 1703. 224 THE TEXTILE FIBRES. horse-hair itself. In place of strong sulphuric acid a solution of zinc chloride may be used with similar results. Amyloid appears also to be a product of natural plant growth, as its presence has been detected in the walls of vegetable cells; it may be recog- nized by giving a blue color with iodin. Very dilute solutions of sulphuric acid, especially in the cold, have no appreciable action on cotton. But if the fibre is impreg- nated with such a solution and then allowed to dry it becomes tendered; this is owing to the gradual concentration of the acid in the fibre on drying. Elevated temperatures also cause the dilute acid to attack the fibre much more quickly and severely than otherwise. In all dyeing and bleaching operations where the use of acid may be required, the above facts should always be borne in mind; the temperature of the acid baths should be not above 70 F., and the acid strength should not be more than 2 per cent. Where higher temperatures are necessary, organic acids should be substituted for mineral acids wherever possible. Acetic acid, for instance, is often used. Whenever cotton is treated with acid solutions or with salts of an acid nature, or which are liable to decompose with liberation of acid, all of the acid should be removed from the fibre or properly neutralized before drying, else the material will be tendered and probably ruined. The action of dilute acid on cotton is probably an hydrolysis of the cellulose molecule, with the formation of cellulose hydrate, causing a structural disorganization of the fibre.* Hydro- chloric acid has an effect similar to sulphuric acid, and the same remarks concerning the use of this latter acid in connection with cotton also hold true for the former. Strong nitric acid has a somewhat different effect ; f it completely decomposes cotton, in * The action of dilute mineral acids on cotton seems to be one of hydrolysis, whereby a molecular change occurs in the fibre substance. This hydrolytic action is supposed to result in the formation of a hydrate of cellulose, having the formula 2C 6 H 10 O 5 .H 2 O. Acetic acid has but small hydrolytic action, and conse- quently has little action on cotton. t The action of nitric acid on cotton fabrics appears to be a peculiar one. The following observations in this respect have been recorded by Knecht: Bleached calico steeped for fifteen minutes in pure nitric acid at 80 Tw., washed and CHEMICAL PROPERTIES OF COTTON ; CELLULOSE. 225 common with other forms of cellulose, oxidizing it to oxalic acid. When boiled with moderately concentrated nitric acid cotton is converted into oxycellulose, a structureless, friable substance possessing a great affinity for basic dyestuffs.* When mixed with concentrated sulphuric acid, however, the action of nitric acid is totally different, the cellulose being converted into a nitrated body, though the physical appearance of the fibre is not appreciably altered. The exact nature of the nitrated compound will depend on the conditions of treatment. Several nitrated celluloses are known and possess commercial importance; they are classified under the general name of pyroxylins.^ Gun- dried, showed a considerable contraction, amounting to about 24 per cent.; the tensile strength also increased 78 per cent. Unbleached yarn, treated in the same manner, also showed a considerable increase of tensile strength, and a pro- portional contraction in length. Weaker acids did not show these results, the fibre being tendered instead of being strengthened. Analysis proved that 7.7 per cent, of nitrogen was present, showing that about two molecules of the acid had com- bined with the cotton. The shrinkage, gain in strength, microscopical appear- ance, etc., of the treated material, all go to show that in addition to the nitration a mercerizing effect has been produced. This appears in the fact that the mater- al exhibits a strongly increased affinity for many dyestuffs, especially the direct cotton colors and some of the acid dyes; while by reason of its not showing any increased affinity for the basic colors there is proof that oxycellulose has not been produced. This action of strong nitric acid on cellulose has been utilized for the preparation of toughened filter-papers which are required to stand high fluid pressures. The filter-paper is immersed in concentrated nitric acid for a brief period and then well washed. * Oxycellulose appears to have the formula C 18 H 26 O 18 . It dissolves in a mix- ture of nitric and sulphuric acids, and from the low number of hydroxyl groups reacting with the nitric acid, it may be concluded that the compound is both a condensed as well as an oxidized derivative of cellulose. Oxycellulose is soluble in dilute solutions of the alkalies, and, on heating, the solutions develop a deep- yellow color. When warmed with concentrated sulphuric acid it gives a pink color similar to that of mucic acid. In general it exhibits a close resemblance to the pectic group of colloidal carbohydrates. (See Cross and Bevan, Cellulose. p. 56.) It is probable that the oxidation products of cellulose obtained by differ- ent means do not all give the same oxycellulose, or, what is more probable, the oxycelluloses which have so far been studied are perhaps mixtures of various different bodies which have not yet been separated and isolated. t The following descriptions of the different nitrated products of cotton cellu- lose have been adapted from Cross and Bevan, Cellulose. In the formulas given the cellulose unit group is taken as Ci2H 2 oO 10 . Cellulose hexanitrate, or guncotton, C^H^O^NOgJIg, is made by the use of 3 parts nitric acid of sp. gr. 1.5 and i part sulphuric acid of sp. gr. 1.84, The 226 THE TEXTILE FIBRES. cotton, a hexanitrated cellulose, is the most highly nitrated product, cotton is immersed in this mixture for 24 hours at a > tejngeratur&-Rot-^ove 10 C.; 100 parts of cellulose yield about 175 parts of the nitrate. This nitrate is insolu- ble in alcohol, ether, or in mixtures of both, in glacial acetic acid, or methyl alco- hol; slowly soluble in acetone. Ordinary guncotton may contain as much as 12 per cent, of nitrates soluble in ether-alcohol mixture. Cellulose pe::tanitrate, C l2 H 15 O 5 (NO 3 ) 5 , is prepared by dissolving guncotton (the hexanitrate) in nitric acid at 80 to 90 C., and precipitating by the addition of sulphuric acid after cooling to o C. The precipitate consists of the penta- nitrate, and is purified by washing with water, then with alcohol, dissolving in ether-alcohol, and reprecipitating with water. The pentanitrate is insoluble in alcohol,. is slightly soluble in acetic acid, and readily so in ether-alcohol; "by treat- mc n with strong caustic potash it is converted into the dinitrate. Cellulose telra- and tri-nitrates (collodion pyroxylin) are formed simultaneously when cotton is treated with a more dilute acid and at higher temperatures, and for a shorter time than in the preparation of the hexanitrate. As these two nitrates- are soluble to the same extent in ether-alcohol, acetic ether, and methyl alcohol, it is not possible to separate them. When treated with a mixture of con- centrated nitric and sulphuric acids, they are both converted into penta- and hexanitrates; caustic potash and ammonia convert them into the dinitrate. Cellulose dinitrate, C 18 H 13 O S (NO 3 ) 2 , is formed through a partial saponifica- tion of the higher nitrates by the action of caustic potash, and also by the action of hot dilute nitric acid on cellulose. The dinitrate is very soluble in ether- alcohol, acetic ether, and in absolute alcohol. Vielle (Compt. Rend., vol. 95, p. 132) has studied the nitration of cotton with different concentrations of acid with the following results: Product Obtained. f Structural features of cotton preserved; soluble 1 -5 02 I ^ in acetic ether; not in ether-alcohol: I<497 [ C 24 H 20 (N0 3 H) 10 10 . 1.496] f Appearances unchanged; soluble in ether-alco- 1.492} \ n l> collodion cotton : i. 49 oJ I Q 4 H 22 (N0 3 H) 9 O n , C 24 H 24 (N0 3 H) 8 12 . (Fibre still unresolved; soluble as above, but solu- tions more gelatinous and thready: Q 4 H 26 (N0 3 H) 7 13 . f Dissolve cotton to viscous solution; products precipitated by water; gelatinized by acetic '** f ether; not by ether-alcohol: I.409J C 24 H 8 (N0 3 H) 6 11 . Friable pulp; blued strongly by iodin in potas- sium iodide solution; insoluble in alcohol sol- vents : C 24 H 30 (N0 3 H) 5 15 , C 24 H 82 (N0 3 H) 4 16 . CHEMICAL PROPERTIES OF COTTON; CELLULOSE. 227 and is used as a basis of many explosives. Soluble pyroxylin is a trinitrated cellulose ; its solution in a mixture of alcohol and ether is called collodion and is employed in surgery and photography. Another derivative, supposed to be a tetranitrated cellulose, is also soluble in ether-alcohol, and its solution has been utilized for the production of lustra-cellulose filaments. By dissolving nitrated cellulose in molten camphor a substance known as celluloid is formed. The action of hydrofluoric acid on cotton and other vegetable fibres appears to be a peculiar one; a transparent, tough, flexible water-proof material being obtained. The product does not appear to resemble parchment obtained by the action of sulphuric acid. It is used as an insulating material and for making the carbon filaments of incandescent electric lamps. Organic acids in solution, even when moderately concentrated, do not appear to have any injurious action on cotton. The non- volatile acids, however, such as oxalic, tartaric, and citric acids, when allowed to dry into the fibre,* act much in the same man- ner as mineral acids, especially at elevated temperatures, f Acetic * The effect of certain acids on the strength of cotton is an important factor in printing. The following table shows the degree of weakening caused by various acids, strips of calico being printed with tragacanth pastes containing 20 grams of oxalic acid per litre, or an equivalent amount of the other acids, and in the first case exposed for four hours to the ordinary temperature, and in the second case steamed for one hour: Acid. I. II. Oxalic 2 c per cent 2t oer cent Tartaric r ' ' 10 Ortho-phosphoric Meta-phosphoric 3M " 15 7C ' '. Pyro-phosphoric **> . . 1C Q " jc e ' Phosphorous 27 " 28 ' t Under similar conditions sulphocyanic acid has but a very slight tendering effect on printed cotton, even under the influence of steaming, but under the influence of dry hot air its tendering action is greater than that of oxalic acid. fThe destructive action of these acids on the cotton fibre is, perhaps, not so much of a chemical nature as mechanical, it being caused by the acids crystal- lizing within the fibre and thus breaking the cell-wall. A dry heat, for instance, in connection with these acids is much more injurious than a moist heat, a fact 228 THE TEXTILE FIBRES. acid, however, being volatile, exerts no destructive action; hence this latter acid is particularly suitable for use in the dyeing and printing of cotton goods, where the use of an acid is requisite.* Tannic acid, unlike other acids, exhibits quite an affinity for cotton, the latter being capable of absorbing as much as 7 to 10 per cent, of its weight of tannic acid from an aqueous solution. Advantage is taken of this fact in the mordanting of cotton with tannic acid and tannins for the dyeing and printing of basic colors. Cotton exhibits a similar attraction for tungstic acid; the expense of this latter compound, however, precludes its adoption as a mordanting agent. Though acids, in general, have such an injurious action on cotton, alkalies, on the other hand, are harmless under ordinary conditions. Dilute solutions of either the carbonated or caustic alkalies, even at a boiling temperature, if air is excluded, have no injurious effect on cotton. In the presence of air alkaline solutions cause an hydrolysis of the cellulose in a manner similar to acids, with the result that the fibre is seriously weakened. The prolonged action of alkalies in the presence of air is an important one to bear in mind in the operations of bleaching, dye- ing, or mercerizing. Boiling solutions of dilute alkalies dissolve or emulsify the waxy and fatty impurities encrusting the cotton fibre, hence these reagents are largely employed in the scouring of cotton goods. The action of alkaline solutions at high temperatures (above 100 C.) on cotton appears, however, to be a destructive one. Tauss has shown that if cotton be digested with solutions of caustic soda under pressure, the fibre is attacked and converted which is of much importance in the drying of cotton prints, where the above- mentioned acids may have been used. * Oxalic acid appears to have a peculiar effect on cotton; it has been noticed that if a piece of cotton cloth be printed with a thickened solution of oxalic acid, dried, and hung in a cool place for about twelve hours, and then well washed, the printed parts exhibit a direct affinity towards the basic dyes. The cotton so treated does not become greatly tendered or otherwise changed. Towards substantive dyes it exhibits considerably less attraction than ordinary cotton, while with alizarin dyes it is partially reactive. Tartaric and citric acids do not produce the same effect, nor does the neutral or acid oxalate of potassium. CHEMICAL PROPERTIES OF COTTON ; CELLULOSE. 229 into soluble products; the degree of decomposition depending on the pressure and the strength of the alkaline liquor, in accord- ance with the following table: Pressure. Strength of Alkali. 3 Per Cent. Na 2 O. 8 Per Cent. Na 2 O. Per Cent, of Cotton Dissolved. i atmosphere 5 atmospheres 10 12. I 15-4 20.3 22.0 58.0 59-o Solutions of ammonia do not act on cotton until quite high temperatures are reached. According to the experiments of L. Vignon, at 200 C. ammonia reacts with cotton cellulose, the result being the evident formation of an amido-cellulose com- pound, the product evincing a greatly increased degree of absorp- tion for dyestuff solutions, especially for the acid coloring-matters, somewhat after the manner of animal fibres. This action of alkaline solutions on cotton under high pressure has an important bearing on the bleaching of this fibre, where it is subjected to such action by boiling with alkalies in pressure kiers. This phase of the question -does not appear to have re- ceived much attention from either the practical bleacher or the theoretical chemist, but it would seem to be worthy of some degree of intelligent research on the part of both. Concentrated solutions of caustic alkalies have a peculiar effect on cotton; the fibre swells up, becomes cylindrical and semi-transparent, while the interior canal is almost entirely oblit- erated by the swelling of the cell- walls. There is a marked gain in weight and strength, while the affinity of the cotton for coloring- matters is materially increased. This effect was first noticed by John Mercer in 1844, and the reaction forms the basis of the modern process of mercerizing, under which title a more com- plete and extensive discussion of this- reaction will be found. Solutions of sodium sulphide appear to have no immediate ten- dering action on cotton, even at a boiling temperature. If the 230 THE TEXTILE FIBRES. sodium sulphide is dried into the fibre after about six weeks, the cotton shows a loss in strength of from 10 to 20 per cent. Also, when sodium sulphide is dried into the fibre at 100 C., the tender- ing amounts to from 10 to 20 per cent. Cotton containing copper sulphide or iron sulphide shows no appreciable amount of tender- ing. When cotton is impregnated with sulphur and exposed to a damp atmosphere for several weeks, its tensile strength is reduced by about one-half. This is perhaps due to the oxidation of the sulphur into sulphurous and sulphuric acids. If cotton, or other forms of cellulose, be treated with a concen- trated solution of caustic soda to which a small amount of carbon disulphide has been added, the fibres swell up, become disinte- grated, and finally form a gelatinous mass. This latter is soluble in a large amount of water, producing a very viscous solution, technically known as -viscose. From this solution hydro- cellulose may be precipitated by sulphurous acid gas, as well as by various other reagents. Precipitation also occurs by simply allowing the solution to stand for some time, in which case the hydrated cellulose separates out as a jelly-like mass. Viscose has received several commercial applications, among which may be mentioned more especially the use of its solutions for the prepara- tion of lustra-cellulose filaments. Though cotton does not show nearly the same degree of affin- ity for acids and alkalies as do the animal fibres, nevertheless it has been shown that cotton does absorb both acids and alkalies from their solutions, even when cold and dilute. The ratio of absorption appears to be 3 molecular parts of acid to 10 molecular parts of caustic alkali.* Vignon, by a study of the thermochem- ical reactions of cotton, has shown that when this fibre is treated with acids or alkalies a liberation of heat takes place,f from which fact it would appear that cotton exhibits in some degree the properties of a very weak acid and a still weaker base. * See p. 216. f Vignon gives the following results in calories per 100 grams of cotton: KOH. NaOH. HC1. H 2 SO 4 . Raw cotton i . 30 i . 08 o . 65 o . 60 Bleached cotton 2.27 2.20 0.65 0.58 CHEMICAL PROPERTIES OF COTTON; CELLULOSE. 231 Strong oxidizing agents, such as chromic acid, permanganates, chlorin, etc., in concentrated solutions, readily attack cotton, converting it into oxycellulose. This substance appears to pos- sess an increased affinity for dyestuffs, but it is of a structureless and brittle nature, hence its formation greatly tenders the fibre. It is said that oxycellulose is indifferent towards the tetrazo dyestuffs; and, in consequence, these may be employed for the purpose of detecting the presence of oxycellulose in cotton mate- rials. In its action towards various metallic salts cotton is very neu- tral, thereby differing considerably from both wool and silk. If the salts, however, are present in a very basic condition, cotton is capable of decomposing them and loosely fixing the metallic hydroxide. Many salts, especially those of an acid nature, will tender the cotton fibre, probably due to the liberation and drying- in of the acid. Consequently, such salts should be avoided or used very carefully with cotton, and any excess should be thor- oughly eliminated by subsequent washing before the material dries. In its behavior towards coloring-matters cotton differs most markedly from the animal fibres. Of the natural dyestuffs, only a few color the cotton fibre without a mordant ; with the coal-tar colors, cotton exhibits no affinity for most of the acid or basic dyes, and these can only be applied on a suitable mordant. The substantive colors, however, are readily dyed on cotton, in a direct manner, and since their introduction the methods of cotton dyeing have been practically revolutionized. There has been much discussion as to whether the phenomena of dyeing with reference to cotton are of a physical or chemical nature. Unlike the animal fibres, cotton does not possess groups of a very distinctly active chemical nature; that is to say, it cannot be said to noticeably exhibit either acid or basic properties. The only groups in cotton cellulose which may be considered chemic- ally active are the hydroxyl groups. These can be rendered in- active by acetytation, and it has been shown * that cotton so * Suida, Farber-Zeit., 1905 232 THE TEXTILE FIBRES. treated does not exhibit any difference in dyeing properties from ordinary cotton, and this leads us to the assumption that in the case of cotton, the phenomena of dyeing rest on a physical dis- sociation of the dyestuff molecule determined by the fibre; that is to say, the process of dyeing with reference to cotton must be attributed (in great measure at least) to the action of dissociation, dissolution, and capillarity; in other words, to purely physical or physico-chemical causes; and purely chemical reactions, if they come into play at all, are of secondary importance. Though resistant to the action of moths and insects in general, cotton is liable to undergo fermentation,* as is evidenced by the formation of mildew f on cotton fabrics stored in damp places. * According to Knecht (Jour. Soc. Dyers & Co/., 1905, p. 189), human saliva has a peculiar and distinct effect on cotton. His experiments show that a piece of bleached calico, saturated with saliva, will absorb considerably more dyestuff on dyeing with substantive colors than untreated cotton. This is not due to mucus, or to any of the salts contained in the saliva, but probably to the enzyme ptyalin, since the saliva loses the power of producing the effect after boiling. Of other enzymes, diastase was also found to have some action, though -\ery slight. This action of saliva on cotton may explain some faults arising in dyeing cotton pieces. f Mildew does not appear as often on white and colored as on gray (unbleached) cloth, which, being sized, is much more liable to this defect. The essential con- ditions for the production of mildew appear to be (i) dampness, (2) lack of fresh air, (3) the presence of certain bodies (such as flour, etc.) suitable as foods for the fungi. The more common varieties of mildew are: (i) Green mildew, a common form generally due to Penicillium glaucum and Aspergillus glaucus, which are closely allied, but which are distinguishable from the way in which the spores are attached. In the former the spores are on branches, while in the latter they are attached to the head; they grow rapidly and generally form rather large patches. (2). Brown mildew is frequently found on cloth, and is due io various species of fungi, of which Puccinia graminis is perhaps the most common. This and the brick-red mildew noticed below are frequently mistaken for iron stains, the color of which they closely resemble. They are easily distinguished by the man- ner in which they occur in small spots, often of a ring shape, and they do not give the Prussian-blue test. (3) Brick-red mildew is not very frequent and the fungus which causes it has not been definitely recognized; it grows rapidly at first, but has no great vitality and after a time the development stops. (4) Yellow mildew, a common variety occurring in large irregular patches and spots. Not requiring much air for its development, it extends much more into CHEMICAL PROPERTIES OF COTTON; CELLULOSE. 233 Though this ferm'entation is often induced by the presence of more or less starchy matter contained in the sizing materials used in finishing the goods, yet pure cellulose itself can also be fermented, and Omeliansky has succeeded in isolating the par- ticular bacillus which destroys cellulose. There has been much discussion as to whether the various treatments to which cotton is subjected during the process of bleaching has any deleterious effect on the strength of the fibre. In this connection O'Neill gives the following interesting results, made to determine the tensile strength of cotton-threads before and after bleaching: Average Weight Required to Break a Single Thread. Before Bleaching. After Bleaching. No i cloth weft-threads 1714 grains 3407 " 35 12 2785 grains 2O20 " 3708 4 2 5 No. i ' ' warp-threads No. 2 " No. 2 " It will be noticed that in two cases out of three the warp- threads are stronger than before, and it may be safely concluded that the tensile strength of cotton yarn is not injured by careful though thorough bleaching, and probably it may be strengthened by the wetting and pressure, causing a more complete and effective bind- ing of the separate cotton fibres, the twisting together of which makes the yarn stronger. the folds of the cloth than do most of the other kinds. It is a yellow variety of the Aspergillus glaucus (Eurotium) and may also be Oidium aurantiacum. (5) Black mildew, due often to fungi belonging to the genus Tilletia, is occa- sionally found; it is very rapid in growth. (6) Purple mildew is rare. (7) Bright pink mildew is also rare. (Textile Mercury, 1906.) CHAPTER XII. MERCERIZED COTTON. i. Mercerizing is a term applied to that process whereby cotton is treated with concentrated caustic alkalies. In its strictest significance, however, it refers most directly to the process of giving cotton a high degree of lustre by subjecting it simultaneously to the chemical action of caustic alkalies and the mechanical action of tension sufficient to prevent contraction. The process is named from John Mercer, who first discovered the effect of strong solutions of caustic alkalies on cotton in the year 1844. It was not until the last decade, however, that the process attained any degree of commercial success; but during the last few years it has given practically a new fibre to the textile industry. Mercerizing, in its essential meaning, relates to the action of certain chemicals on cellulose, whereby the latter is changed to a product known as cellulose hydrate ; though, technically, the term has come to mean the process concerned with the imparting of a silk-like lustre to the fibre. As generally understood, it consists briefly in impregnating cotton yarn or cloth with a rather concentrated cold solution of caustic soda and subsequently washing out the caustic liquor with water, the material being either held in a state of tension during the time it is treated with the caustic alkali in order to prevent contraction, or stretched back to its original length after treatment with tha alkali, but previous to washing. In either case, the material must be in a state of tension during the process of washing. There are two separate phases of the mercerizing process represented in the above operations which must be separately understood in order 234 MERCERIZED COTTON. 235 to comprehend the exact nature of the change which takes place in the appearance of the fibre; the one is the chemical action of the caustic soda, and the other is the mechanical effect brought about by the tension. The action of the caustic alkali is to effect a chemical transformation in the substance of the fibre, a further chemical reaction taking place when this product is treated with water. As already pointed out (p. 219), cellulose has the prop- erty of combining with caustic soda to form a product known as alkali-cellulose, Ci2H 2 oO 10'. NaOH. The formation of this com- pound does not appear to disintegrate the organic structure of the fibre-cell, provided the proper conditions are maintained. The alkali-cellulose, however, is apparently a rather feebly com- bined molecular aggregate, and does not exhibit much stability towards reagents in general. It is even decomposed by the action of water, the effect of the latter being to disrupt the bond of molec- ular union between the\alkali and cellulose, with the consequent re-formation of caustic soda and the introduction of water into the cellulose molecule. This fatter substance, which may be termed cellulose hydrate, forms the chemical basis of mercerized cotton. The theory that caustic soda effects a true chemical combination with cellulose is somewhat supported by the fact that mercerized cotton undergoes chemical changes to which ordinary cotton is not susceptible. For instance, the former is much more readily dissolved by a solution of ammoniacal copper oxide; it is chem- ically reactive with carbon disulphide with the formation of soluble cellulose thiocarbonates; alkali-cellulose also reacts with benzoyl chloride and acetic anhydride, giving rise to cellulose benzoates and acetates. The nature of the chemical change in mercerized cotton, however, is rather ill defined; it no doubt can be included under that class of reactions which stands somewhat midway between ordinary physical and chem- ical changes, and is to be particularly observed in connection with those bodies possessing a high degree of molecular com- plexity, such as various colloidal substances and the large num- ber of naturally occurring carbohydrates, starches, gums, etc. The fact that there is no evidence of disorganization in the fibre- cell, as may be observed from its physical properties and micro- 236 THE TEXTILE FIBRES. scopic appearance, is a strong argument against true chemical change, which would necessitate a rearrangement in the atomic grouping in the substance of the fibre. This would result in a decomposition of its organized structure, which would at once be manifested in a decrease in the tensile strength, and an actual breaking down of the fibre itself. But mercerized cotton shows no such change; on the other hand, its tensile strength is con- siderably increased, and the fibre-cell shows no tendency towards physical decomposition. When the cotton fibre is immersed in a concentrated solution of caustic soda it undergoes a peculiar physical modification; it appears to absorb the alkali,, swelling to a cylindrical form, so that it presents more the appearance of a hair than a flat ribbon ; the fibre also untwists itself and becomes much straighter, at the same time shrinking considerably in length. The internal portion of the fibre acquires a gelatinous appearance, becom- ing somewhat translucent to light, though it is firm in structure; the surface of the fibre shows a wrinkled appearance transversely, due to a somewhat unequal distension of the inner part. There is a small degree of lustre on portions of the surface, but, due to the uneven stretching and wrinkling of the external superficies, the smooth lustrous portions are irregular in occurrence and not very extensive in area. The fibre also shows a slight increase in weight. These changes in the physical appearance of the fibre are accompanied by a remarkable increase in the tensile strength, amounting in most cases to as much as from 30 to 50 per cent. ; the fibre also acquiring a greater power of absorption towards many solutions, most notably those of dyestufls. The increase in tensile strength is probably due to the fact that mercerizing causes the inner structure of the fibre to become more solidly bound together by a filling up of the interstitial spaces between the molecular components of the cell- wall. In this manner the fibre as a whole is given a greater degree of solidity; the internal strain between the cell-elements (which must be quite considerable after the drying out and shrinking of the ripened fibre) is lessened no doubt, and hence adds to the unified strength of the fibre. From the fact that the fibre shrinks in length in mercerizing, it is probable that MERCERIZED COTTON. 237 the cell-elements have contracted transversely on the collapse of the fibre canal, and, on being distended again by the action of the caustic alkali, these cell- elements become shortened longitudinally and are more tightly packed together. The increased affinity for dyestuffs exhibited by mercerized cotton is not to be considered a new inherent property of the modified cellulose induced by a change in its chemical composition. It is no doubt a result of the modified physical structure of the fibre itself; that is, when the cell-elements have become distended, like a sponge,, they have a greater power of absorption and retention of liquids than when in a flattened and collapsed condition. The high lustre imparted to cotton by mercerizing is brought about by other conditions than the mere action of the caustic alkali.* In the swelling of the cell-walls and consequent con- traction of the fibre, the surface remains wrinkled and uneven, due to the unequal strain of expansion. If, however, the ends of the fibre are fixed, and thus prevented from contracting when subjected to the chemical action of the alkali, the swelling of the cell- walls will cause the surface to become smooth and even, and similar to a polished surface capable of reflecting light with but little scattering of the rays. Another condition which also has much to do with the production of the lustrous appearance is no doubt to be found in the physical modification of the cell elements themselves. When the fibre swells up under the action of the caustic alkali, its substance becomes gelatinous and trans- lucent, and this has a marked effect on the optical properties of the fibre, and enhances the lustre considerably by lessening the proportion of light absorbed. f * It has been claimed that the mercerizing effect may be obtained without tension by the addition of glucose to the alkaline bath. The addition of other substances, such as ether, aluminium chloride, etc., have been claimed to pro- duce the same result. But it is to be doubted whether a high lustre is obtained by any of these methods. f Dr. Frankel has advanced the opinion that the high lustre exhibited by mercerized cotton is mainly due to the fibre having lost its thin cuticle during the process. But this theory is overthrown by the fact that if mercerized cotton is again subjected to the action ot cold strong caustic soda, it contracts nearly as much as raw cotton would do, and loses its silky lustre entirely. 238 THB TEXTILE FIBRES. Considerable difference is to be observed in the strength and elasticity of cotton mercerized without tension and that mercerized with tension. Buntrock, in a research on this subject, found that cotton yarn mercerized without tension showed an increase of 68 per cent, in its tensile strength,* whereas the same cotton mercerized under tension gave an increase of only 35 per cent. With respect to the elasticity of the yarn, the same chemist ascertained that the untreated cotton employed in his experiments stretched u per cent, of its length before breaking; the amount for cotton mercerized without tension was 17 per cent., an increase of 54 per cent.; cotton mercerized under tension showed no increase in elasticity at all, and could only be stretched the original n per cent, before breaking. These figures, of course, are not absolute for all varieties of cotton, but will vary within considerable limits, depending upon the character of the raw cotton employed. Attention must also be drawn to the fact that the figures for the tensile strength and elasticity quoted above were obtained by using spun yarn and are not based on the single fibre. Of course it is the strength of the yarn which is desired in practice, but the figure for this is not necessarily that for the fibre itself. In mercerizing yarn or cloth, it must be borne in mind that the fibres shrink considerably, and in doing so become more closely knit together; therefore the increase in tensile strength, as ascertained by Buntrock, represents really the greater coherence of the fibres to one another rather than an increase in the strength of the individual fibre, because in breaking a yarn spun from a large number of fibres there is little or no actual breaking of the fibres themselves, but only a pulling apart of the latter. The same criticism also applies to a determination of the elasticity. It would, perhaps, be more scientific to determine the breaking strain and elasticity of the separate fibres rather than that of the yarn or cloth; but it may be assumed, with considerable show * Grosheintz gives the following results of some experiments on the effect of mercerization on the tensile strength of cotton : Unmercerized yarn broke with a load of 356-360 grams; same yarn mercerized in cold aqueous caustic soda (35 Be.) broke with 530-570 grams; same yarn mercerized with cold alcoholic caustic soda (10 per cent.) broke with 600-645 grams; same (except that hot alcoholic caustic soda was used) broke with a load of 690-740 grams. MERCERIZED COTTON. 239 of reason, that these figures of Buntrock will represent a fair relation between the strength and elasticity of the individual fibres. The cause of the lesser increase in tensile strength of cotton mercerized under tension as compared with that of the same cotton mercerized without tension is to be attributed to the fact that when the shrinkage of the fibre is prevented by the application of an external force the cell tissues cannot become as compact as otherwise, and there is also an internal strain induced which lessens the ultimate strength of the fibre. This latter condition also accounts for the lack of any increase in the elasticity of the mercerized fibre; the fibre when mercerized under tension is already in a stretched or strained condition, and can hardly be expected to give the same degree of elasticity as if tension had not been applied, as a certain part of its elasticity has been used up by the stretching. 2. Conditions of Mercerizing. The proper conditions for carrying into practical operation the mercerizing process are simple and easily realized. Caustic soda is the most suitable and convenient reagent * for bringing about the hydration of the cellulose; and it has been found that a solution of density between 60 and 70 Tw. gives the best results. Caustic soda solutions of less density than 1 5 Tw. have scarcely any action on cotton; the maximum effect appears to be produced by a con- centration of about 60 Tw., though the difference between this and that obtained at 50 Tw. is not very marked, and even at 40 Tw. the mercerizing action of the alkali is quite strong. Other reagents than caustic alkalies, however, may be employed for the hydrolysis of the cotton. Concentrated mineral acids, such, for instance, as sulphuric acid at a density of 100 to 125 Tw., will bring about the mercerizing effect more or less perfectly; the same is also true of certain metallic salts, most notably the chlorides of zinc, calcium, and tin. Beyond a mere theoretical and chemical interest, however, mercerizing by means of such * Solutions of caustic potash probably give a somewhat better lustre, and the shrinkage of the fibre is less than with caustic soda. But these small advantages are not sufficient to compensate for the extra expense which would be entailed by the use of caustic potash. 240 THE TEXTILE FIBRES. reagents has no practical value.* The addition of various chem- icals, however, has been made to the caustic alkali solution with beneficial results. It has been observed, for instance, that the addition of zinc oxide has a very marked effect, and probably is of considerable value in the practical working of the process. The addition of glycerol, though perhaps of some benefit in assisting in the even 'and thorough penetration of the liquor into the fibre, can hardly be said to appreciably modify the general operation of the alkali.| Previous treatment with Turkey-red oil is also of benefit for the same reason; this is also true of such substances as sodium silicate, sodium aluminate, and soap. The temperature at which the reaction is carried out should not be higher than the usual atmospheric degree; in fact, it has been recommended to lower the temperature of the caustic soda solution by the addition of ice, but this procedure does not appear to add anything of material advantage. At elevated temperatures caustic soda appears to exert a destructive effect on cotton, prob- ably due to the formation of oxycellulose through hydrolysis and subsequent oxidation. Beyond a certain temperature the mer- cerizing effect rapidly diminishes, and at the boil it is scarcely appreciable, t The best results appear to be obtained when the * The use of sulphide of sodium or potassium instead of caustic alkali has been proposed; but the process yields very uncertain results. It is claimed that by adding ether to the caustic soda solution good mercerization can be obtained with but little contraction of the fibre, but as this process requires fifty parts of ether to twenty parts of caustic soda solution, the expense renders it ridiculously impracticable. It is said that the addition of carbon bisulphide to the bath of caustic soda very materially increases the lustre; this causes a disintegration of the fibre, however, through the formation of viscose (see p. 230); hence the treat- ment should be very brief, otherwise the cotton will be seriously tendered. The mercerized fibre at first is as stiff as horse-hair, but this effect can be removed by repeated washing. The sulphur can be removed from the cotton by washing in a solution of sal-ammoniac, and this should be done before the material is treated with an acid bath, as the latter would cause a precipitation of sulphur on the fibre and so spoil the lustre. f In the practical manipulation of the mercerizing process it has been found that the impregnation with caustic liquor is greatly facilitated by the addition of 5 per cent, of alcohol on the weight of the caustic soda. J Beltzer, however, claims that caustic soda solutions of 65 Tw. gave the same results in mercerizing at 90 C. as at 15 C., but the cotton mercerized at the higher temperature was much more transparent than the other. The lustre, MERCERIZED COTTON, 241 .emperature is maintained at 20 C. or lower. Above this point the contraction of the fibre (which may be taken as a measure of the degree of mercerization) grows less and less with rise of tem- perature. The mercerizing action of caustic soda is rather a rapid one, as it requires only a few minutes for its completion; in fact, it appears to take place simultaneously with the impregnation of the fibre by the liquid. In ten minutes mercerization is prac- tically complete, and lengthening of the time does not increase the mercerizing effect; in fact, too long a contact of the cotton with the caustic alkali is to be avoided, especially if the impreg- nated fibre is exposed to the air, as there is danger of a breaking down of the cellular structure and a consequent deterioration in the strength of the fibre. The time of immersion also appears to be independent of both the temperature and the concentration of the alkali. There are two ways in which the tension may be applied in mercerizing: (a) The material may be held in a state of tension during the time of its treatment with the caustic alkali, and until the alkali has been washed out, in which case the tension should be so maintained that the material cannot shrink; (b) the ten- sion may be applied after the material has been treated with the caustic alkali, but before the latter is washed out, in which case sufficient tension should be exerted to stretch the material back to its original length. If the tension is not applied until after the alkali has been removed from the fibre, no lustring effect is pro- duced; it is absolutely essential that the stretching should take place while the fibre is in the form of an alkali-cellulose, and before it has been converted by treatment with water into hydrated cellulose. According to the experiments of Herbig, the stretching force necessary to keep the cotton in its original length during mercer- ization is only from a quarter to a third of that necessary to do the stretching after mercerization; but there appears to be no however, was in no wise inferior. If the mercerization be conducted at 90 C., it is necessary to keep the cotton entirely immersed, to guard it from contact with the air, otherwise it will become seriously weakened. 242 THE TEXTILE FIBRES. appreciable difference in the lustre obtained. It would appear, however, that stretching beyond a certain point ceases to increase the lustre, and to obtain the maximum lustring effect it is not necessary to stretch the cotton back to its original length. Her- big concluded that stretching during mercerization is disadvan- tageous, and it is best to mercerize the yarn loose, wring it, and only stretch while rinsing, as the required stretching force is then quite small. The best time for stretching,, then, is during the conversion of the soda-cellulose into the hydrocellulose. If the stretching does not take place until after rinsing, almost twice the force is necessary to restore the yarn to its original length, as when in contact with the lye, and the lustre is decidedly inferior. The stretching force also appears to depend on the twist, being greater in proportion as the twist is harder.* * Herbig gives a summary of his experimental results as follows : 1. Loose yarn mercerized without any stretching, whether long- or short- stapled, and whether with or without a hard twist, has less lustre than unmer- cerized yarn. But even with a very slight tension the lustre is greater. 2. Both with long- and short -stapled cotton the lustre only becomes marked when the stretching force is sufficient to bring the yarn back to its original length. 3. Stretching beyond the original length does not give any increase in lustre. 4. Considerable difference is observable in the stretching force needed between loose mercerization followed by stretching in the lye, and keeping the cotton at its original length during mercerization, as in the latter case only one-third to one-quarter of the force is necessary to produce the silky lustre. 5. The stretching of the yarn requires only a small force when mercerized loose and if applied when rinsing is actually in progress; for the best time for stretching is during the conversion of the soda-cellulose into hydrocellulose. 6. When rinsing is over, twice as much force is needed to restore the original length as is required for yarn still in contact with the lye; and yarns so treated contract somewhat on drying, and exhibit an inferior lustre. 7. The stretching force necessary in mercerizing yarn varies with the twist, and in general is greater in proportion as the twist is harder. 8. The production of the silky lustre does not depend primarily on the amount of force employed in stretching, as soft yarn with only a small amount of twist can be lustred. 9. The production of the silky lustre is independent of the cotton being long- or short-stapled, as short-stapled American cotton with even a loose twist can be given a silky lustre. 10. The production of a high degree of lustre depends to a considerable extent on the fineness of the fibre and its natural lustre. This is apparent in mercer- izing sea-island and Egyptian cotton. MERCERIZED COTTON. 243 By the washing of the material after steeping in caustic alkali, a twofold object is gained. In the first place, the action of the water on the alkali-cellulose is to effect a chemical transforma- tion into cellulose hydrate, and this action is as really essential to mercerizing as the action of the caustic soda itself. In the second place, the washing is conducted for the purpose of remov- ing all excess of caustic alkali from the material.* Caustic soda is held quite tenaciously by cotton, and it requires a very thorough and long-continued washing to remove the last traces of this compound. In order to shorten the period required for washing, it is customary to give the cotton first a rinsing in fresh water, after which the tension may be relieved, and then to wash with acidulated water, using acetic acid for this purpose. f On dry- ing the material without further washing, it will be found that the acetic acid has imparted to the cotton a certain degree of " scroop," somewhat after the nature of silk, without in any man- ner tendering the fibre. If other acids, and especially mineral acids, are employed for washing, a subsequent rinsing with fresh water and soaping is necessary for the purpose of neutralizing all of the acid, which would otherwise seriously tender the goods on drying, unless the amount of acid employed is so accurately adjusted as not to leave any free acid in the fibre. The character of the fibre employed has a considerable influ- ence on the success of the mercerizing process. From the very nature of the fact that a considerable degree of tension must be applied to the fibre during the process in order to obtain the desired lustre, it would be natural to expect that the longer the staple of the fibre the more readily would it lend itself to the requirements of the operation. And such, indeed, is found to be the case; the long-stapled sea-island J and Egyptian varieties * When mercerized cotton is rinsed with ammonia instead of water it retains its gelatinous, parchment -like consistency throughout the rinsing, and can be stretched to its original length without breaking. If the cotton is then rinsed with water while still stretched, the fibre regains its original appearance and acquires a lustre as good as that obtained in the usual way. t Sulphuric acid is also much used in the washing. The acid employed is of J Be*, strength, and at a temperature of 50 C. % The preparation by combing of cotton for mercerizafion has a considerable 244 THE TEXTILE FIBRES. of cotton are those especially adapted for use in the preparation of mercerized cotton, while the shorter- stapled varieties are but little employed for this purpose, as the lustre obtained with them is by no means as pronounced.* The quality of being mercerized, however, is not an inherent property of any special variety of cotton, as was formerly supposed to be the case; any variety of cotton is capable of mercerization, the only essential being that the fibre shall be maintained in a state of tension. In order that this condition be realized with short-stapled fibres, the yarn operated upon must be tightly twisted in order to present suffi- cient cohesion among the individual fibres to allow of the high tension required; this, on the other hand, prevents an even and thorough psnetration of the caustic alkali into the substance of the fibre, so that, on the whole, the results obtained with short- stapled fibres are not at all comparable with the long-stsp^d varieties.f By later improvements in -the manner of applying influence on the subsequent lustre of the yarn. Sea-island cotton possesses a rather silky fibre to begin with, and this is made more adaptable to the production of a high lustre by combing, in which operation the fibres are arranged parallel, and still further by gassing, which burns off the minute outer hairs. Yarns pos- sessing considerable lustre were made in this manner with fine counts of sea- island cotton long before the discovery of lustring by mercerization, and it was always recognized that the parallelism of the fibres so obtained by combing (and sometimes a second combing) was a great factor in the production of a silky and lustrous yarn. * Fabrics of vegetable fibres (cotton or liner) may also be mercerized in pat- terns by printing on certain compounds capable of resisting the action of the caustic soda in the subsequent mercerizing process. Resists suitable for this purpose are, in the first place, organic compounds which readily coagulate, such as albumin and casein; and secondly, such salts, acids, or oxides which may act by neutralizing the caustic alkali, or from which a hydrate may be precipi- tated on the fabric by its action. Such compounds, for instance, as the salts of aluminium or zinc, organic acids, and the oxides of zinc, aluminium, or chromium are quite suitable. Very beautiful effects are said to be obtainable by this process. f Boucart gives the following reasons why only long-stapled cotton, and that only in particular counts, gives good results on mercerization. A simple thread consists of a sort of twisted wick composed of nearly parallel fibres. The twist depends, as regards the angles it makes with the length of the thread, both upon the kind of cotton and upon the count of the yarn. Of the two sorts of simple yarns, warp- yarns have more cohesion among their elements than tensile strength, while the reverse is the case with weft -yarns. The result is that under gradually MERCERIZED COTTON. 245 the tension, however, it would seem that, by realizing the proper mechanical conditions, even cotton of comparatively short staple will be capable of being mercerized in a more successful man- ner than heretofore.* 3. Properties of Mercerized Cotton. Outside of its high lustre and somewhat increased tensile strength, mercerized cotton exhibits but few apparent differences from the ordinary fibre. increasing tension weft -fibres slide past one another without breaking, but warp- fibres break before any such occurrence takes place. The degree of twist also depends on the mean staple, and the angle between the thread and the axis at any point is proportional to the length of the thread. The degree of twist which is required to make the cohesion exceed the tensile strength depends naturally on the strength of the fibre. The mercerizing process tends to shorten each individual fibre, and this shortening is resisted by tension in the direction parallel to the axis of the thread. Hence the greater the angle the thread makes with that axis the less is the effect of the tension, and if any portion of the fibre is at right angles to the axis it is not affected by the tension at all. Hence a simple warp-thread can only receive a medium amount of gloss from mercerization, and the less the greater the twist. Slightly twisted threads must give the best lustre, but if the cohesion of the fibres is less than the contractile force exerted by the lye, the fibres slip past each other and no lustre is produced. But if the weft- threads are fixed, as in piece goods, they take a better lustre than the warp, although the latter is usually made of better cotton. Short-stapled cotton lustres badly because it must be more tightly twisted. The best lustre of all is obtained with twofold twist, in which the outer fibres lie parallel to the axis, and the yarn should be well singed to remove projecting fibres. * The process of mercerizing has been subject of late to a great number of patents, especially by Thomas and Prevost of Germany. This has resulted in considerable litigation in many countries. As far as the actual chemical process itself is concerned, however, there does not appear to have been any material advance beyond the facts first discovered by Mercer and patented by him in 1850; with regard to the element of carrying out the process under tension, it may be said that this was first described and patented by Arthur Lowe in 1890, and this included the application of tension either during or after the treatment with caustic alkali. Lowe's object in stretching the material, however, was primarily to pre- vent the loss encountered by the shrinkage of the goods, though he does also make a specific statement that the cotton acquires an increased lustre and finish by the process. The only novelty put forward by Thomas and Prevost was the use of a particular kind of cotton, that is, long-stapled varieties; but as both Mercer's and Lowe's patents claim the use of all varieties of cotton, it is difficult to see on what ground Thomas and Prevost can substantiate their claim for a patent. Patents covering the process of mercerizing appear to be without foundation; though for machinery and appliances for carrying out the same such patents may be perfectly legitimate. Recent decisions on this matter in the United States have invalidated Thomas and Prevost's patents in this country. 246 THE TEXTILE FIBRES. Towards dyestuffs and mordants it is rather more reactive, and consequently will dye deeper shades with the same amount of dyestuff than ordinary cotton ; this property is rather to be ascribed to the increased absorptivity of the fibre than as the result of any chemical modification of the cellulose composing it; it is also FIG. 62. Mercerized Cotton. ( X35O.) (Micrograph by author.) independent of the method of mercerizing, that is, whether accom- panied by tension or not. Microscopically the mercerized cotton fibre exhibits a con- siderable difference from that of ordinary cotton. Whereas the latter, when viewed under the microscope, appears as a twisted flat band with thickened edges, and in cross-section like a col- lapsed tube, mercerized cotton appears as a rather smooth cylindri- cal fibre, the cross-section of which is more or less circular. It rarely happens that a fibre absolutely loses all of its twist, though the degree of mercerization may be measured by the freedom of the fibre from irregularities and twists. Under ordinary con- ditions when the cotton is mercerized in a state of tension, it will MERCERIZED COTTON. 247 also be found that many fibres will remain in their original form, or unmercerized, whereas others will be mercerized only in portions of their length. The microscopical examination of mercerized cotton is important in determining just how perfectly the process has been carried out, which may be judged by the relative number of unmercerized or partially mercerized fibres which may be present. Cotton may be mercerized either in the form of yarn or of cloth, and it is principally done in the unbleached condition. There has been some dispute as to which is best : to mercerize first and bleach, or to bleach first and then mercerize; experience, however, appears to favor the first method. In the bleaching operations, which usually involve a rather severe treatment of the cotton first with moderately strong alkalies and subsequently with solutions of bleaching powder, the fibre suffers more or less chemical alteration, so that in the mercerizing process it can -no longer enter into proper chemical union with the caustic soda employed; and hence complete true mercerization is not effected. Although cotton should be thoroughly scoured (" boiled out ") before being mercerized, it is best not to use alkalies for the pur- pose, but to employ Turkey-red oil (or other suitable sulphated oil) or soap. If bleaching is carefully conducted after merceriz- ing, the injury to the lustre of the fibre is very slight. Mercerized cotton does not require a prolonged boiling in alkalies previous to the operation of bleaching as with ordinary cotton. To obtain the best conditions for high lustre, yarn should be well " gassed " (singed) before mercerizing, as otherwise the external, hairy fibres remain loose and cannot be subjected to tension. As a result, these fibres shrink, and, remaining without lustre themselves, hide to a certain extent the lustred surface of the yarn. More- over, caustic soda has a felting action on these free filaments, and felting is especially harmful to lustre. In mercerizing cloth the action taking place between the sizing materials (always present to a greater or lesser degree in cotton cloth) and the caustic alkali is sufficient at times to raise the temperature considerably, which may result in a deficient lustre. In such cases recourse must be had to artificial cooling 248 THE TEXTILE FIBRES. by addition of ice or a current of cold water in order to prevent an undue rise in temperature. When mercerized cotton is to be bleached, it is best, after the first rinsing, to remove the major portion of the caustic soda and arrest the mercerization, not to rinse again in acidulated water, as would ordinarily be done if the material were not to be immedi- ately bleached. The small amount of caustic soda which still remains in the cotton acts in a beneficial manner in bleaching. A silky lustre resembling that produced by mercerization can be given to cotton cloth by means of what is known as a calender finish. This is accomplished by passing the cloth between rollers under heavy pressure, one of the rollers being engraved with obliquely set lines ruled from 125 to 600 to the inch. The effect is to produce a great number of parallel, flat surfaces on the cloth, which causes it to acquire a high lustre. By conducting the opera- tion with hot rollers quite a permanent finish can be produced which closely approximates mercerized cotton. Cloth so fin- ished, however, loses its lustre in a large degree on washing. The method is chiefly known as the " Schreiner process." CHAPTER XIII. SEED-HAIRS OTHER THAN COTTON. i. Bombax Cotton. Besides the cotton derived from the ordi- nary species of the cotton plant (Gossypium family), there is a very similar seed-hair fibre obtained from a plant known as the cotton- tree and belonging to the Bombacea family. The fibre is known in trade as vegetable down or bombax cotton. It grows almost exclusively in tropical countries. The fibre is soft, but rather weak as compared with ordinary cotton; in color it varies from white to a yellowish brown, and it is quite lustrous. The fibres have a length of from 10 to 30 mm., and a diameter of from 0.020 to 0.045 mm - Owing to its weakness and lack of elasticity, bombax cotton is not used by itself as a textile fibre; it is some- times mixed with ordinary cotton and spun into yarn, but it is principally used as a wadding and upholstery material. In its physical appearance, bombax cotton differs from true cotton in not possessing any spiral twist and showing irregular thickenings -of the cell- wall; the fibre usually consists of one cell, though occasionally it may have two. Unlike true cotton, the fibre does not grow directly from the seed, but originates at the inner side of the seed-capsule. There are several varieties of plants from which vegetable* down may be obtained. In Brazil it is obtained from the Bombax heptaphyllum and B. ceiba, and the product is known as Paina limpa or ceiba cotton. This is also produced in the West Indies and other parts of tropical America. In Bombax ceiba the fibre has a length of from i to 1.5 cm., while in B. heptaphyllum the fibre length is from 2 to 3 cm., being by far the longest and strongest variety of bombax cotton. B. malabaricum, of South 249 2$ THE TEXTILE FIBRES. Asia and Africa, has fibres from i to 2 cm. in length ; this latter is known in India as Simal cotton or red silk-cotton. Other varieties of Bombax plants are B. cumanensis of Venezuela, giving a product known as " lana del tambor " or " lana vejetale "; B. pubescens and B. mllosum from Brazil; B. carolinum from South America; B. rhodognaphalon of West Africa, the fibre of FIG. 63. Vegetable Down. (X35Q.) E, lace-like structure at base; F, fibre folded on itself; P, point of fibre; C, thin cell-wall. (Micrograph by author.) i which is known as wild kapok and is used largely for the stuffing of pillows. The microscopical characteristics of vegetable down are as follows : The fibre consists of a single cell, possessing a cylindrical shape, being rather thick at the base and tapering gradually to the point. The base of the fibre is frequently swollen and exhibits a lace-like structure (see Fig. 63). The cell- wall is usually very thin, occupying not more than one-tenth the width of the SEED-HAIRS OTHER THAN COTTON. 251 fibre. The cross-section is circular and not flat, as in the case of cotton. The inner canal is partly filled with a dried-up proto- plasmic membrane. In its chemical constitution vegetable down differs from ordinary cotton in containing a certain amount of lignified tissue; consequently it furnishes a yellow coloration when treated with anilin sulphate or with iodin and sulphuric acid, and by these tests it may readily be distinguished from true cotton. Owing to its lignified nature the fibres also swell but slightly when treated with Schweitzer's reagent. The fibre from the Bombax ceiba is distinguished by its decidedly yellowish color. The seed-hairs of the Eriodendron anjractuosum (or Bombax pentandrum) are very similar to the preceding varieties of vege- table down. It gives the product known in Holland as kapok. In both their physical appearance and chemical properties it is almost impossible to distinguish between kapok and ceiba cotton. Kapok is obtained from South Asia and the East Indies, and is very extensively used as upholstery material, and also for the stuffing of life-saving belts on account of its low specific gravity. The hair-fibres of the Ochroma lagopus (from the West Indies) have a length of from 0.5 to 1.5 cm., and are thicker in the middle than at the ends. The cell-wall is much thicker than with bombax cotton, and the fibres are also more highly lignified than those of the latter. They occur in trade as edredon vegetate or pattes de lievre, and the product comes mostly from Guade- loupe and Martinique. The Ouate vigitale of the French trade is a mixture of fibres from Bombax, Ochroma, and Chorisia varieties. The Cochlospermum gossypium of India and the Chorisia speciosa and C. insignis of South America also furnish fair quali- ties of vegetable down. Pulu fibre can also be classed under the general name of vegetable down. It is the hair obtained from the stems of fern- trees, more especially the Cibotium glaucum of the Hawaiian Islands. The fibres are lustrous, of a golden brown color, very soft, and not especially strong. They have a length of about 5 cms., and are composed of a series of very flat cells, pressed 25 2 THE TEXTILE FIBRES. together in a ribbon-like form. The fibre is only employed as an upholstery material and is never spun. Similar fibres are also obtained from Cibotium barometz, C. menziesii, and C. chamissoi; the second one produces the best fibre. 2. Vegetable Silk. Another seed-hair which is utilized to some extent as a fibre is the so-called vegetable silk or Asdepias cotton. This fibre is obtained from Asdepias syriaca and A. incarnata or common milkweed or silkweed. The plant grows extensively in America. The surface fibre from the seed-pods * is used for upholstery material; it has also been used in France for the manufacture of w r oven fabrics, being spun with 80 per cent, of w r ool, and made into a fabric known as " silver cloth." The fibre of vegetable silk is quite brittle in nature and pos- sesses but little tensile strength; hence attempts at spinning it by itself have not proved very successful. Its chief physical quality is its high degree of lustre and softness. When examined under the microscope, the fibre exhibits thickened ridges in the cell- wall which serve to distinguish it from Bombax cotton. Each fibre consists of a single cell, usually somewhat distended at the base. It is of a yellowish white color; the length varies from 10 to 30 mm. and the diameter from 0.02 to 0.05 mm. As vegetable silk is somewhat lignified, it may be distinguished from true cotton by giving a yellowish brown coloration with iodin and sulphuric acid, and a yellow coloration with anilin sulphate. Its micro- chemical reactions are very similar to Bombax cotton, though with phloroglucol and hydrochloric acid the latter gives a dull violet coloration, while vegetable silk gives a bright red-violet coloration. There are several minor varieties of vegetable silk, chief among which are the following; Asdepias curassavica and A. volubilis from the West Indies and South America; Calo- tropis gigantea and C. procera of southern Asia and Africa: several species of Marsdenia from India . Beaumontia grandi flora from India, and different varieties of Strophantus from Senegal. * The same plant also furnishes a bast fibre which is fine, long, and glossy, and said to be equal in strength and durability to hemp. SEED-HAIRS OTHER THAN COTTON. 253 The different varieties of vegetable silk are very difficult to distinguish from one another. They all possess a soft feel and a high silky lustre. In color they vary from almost pure white to a slight orange-yellow. In thickness the fibres usually vary from 35 to 60 //, though occasionally they may reach 80 //. In length they vary from 10 to 50 mm. The fibre has but little plia- bility or elasticity, hence is very brittle; this is due to the very thin cell-wall. All varieties exhibit the thickened ridge in the cell-wall, which gives the fibre the appearance of being uneven in thickness. In cross-section, these ridges are usually semi- circular, though sometimes flat and broad. The cross-section of the fibre itself is usually circular. The seed-hairs of the Beaumontia grandi flora furnishes prob- ably the best variety of vegetable silk, as the fibre is not only the most lustrous but is also the most purely white, while it also possesses the greatest tensile strength and the fibres are easily separated from the seeds. The fibres are from 3 to 4.5 cm. in length and from 33 to 50 jj. in diameter. The thickness of the cell- wall is about 3.9 JJL. At the base the fibre is somewhat enlarged. The fibre of Calotropis gigantea * is from 2 to 3 cm. in length and from 12 to 42 /* in diameter; the cell- wall is from 1:4 to 4.2 /* in thickness. At the base the fibre is somewhat enlarged and * Calotropis gigantea, or giant asclepias, also yields a bast fibre said to be of very superior quality, somewhat resembling flax in appearance and of the same strength. The vegetable silk enveloping the seeds is known in India as madar floss. The bast fibre is said to show a high degree of resistance to moisture; according to Spon, samples exposed for two hours to steam at two atmospheres pressure, boiled in water for three hours, and again steamed for four hours, lost only 5.47 per cent, in weight, whereas flax under the same conditions lost 3.50 per cent., manila hemp 6.07 per cent,, hemp 6.18 to 8.44 per cent., and coir 8.14 per cent. As to the strength of the fibre, Dr. Wright's tests give it a breaking strain of 552 pounds as compared with 404 pounds for sunn hemp; Royle's tests give it a breaking strain of 190 pounds as compared with 160 pounds for Russian hemp and 190 pounds for Jubbulpore hemp from Crotalaria tenuifolia. The vegetable silk from Calotropis gigantea is known in Java under the name of kapok, though this name is also given to the product of the Eriodeniron anjractuosum and Bombax pentandrum. The fibre is said to have been made into shawls and handkerchiefs, but it hardly possesses sufficient strength to be spun alone. The C. gigantea is not only a fibre plant, as it also yields gutta-percha, varnish, dye, and medicinal substances. 254 THE TEXTILE FIBRES. flattened, though this formation is not so perceptible as in the case of Beaumontia grandiflora. The fibre of Calotropis gigantea is known in Venezuela as algodon de seda. The fibres from the various species of Marsdcnia are very uniformly cylindrical and straight. In length they vary from i to 2.5 cm. and in diameter from 19 to 33 JJL. The cell wall has an average thickness of 2.5 ju. The fibre of Strophantus differs somewhat from other varie- ties, in that at the base there occur pores in the cell- walls. This fibre is also not so easily removed from the seeds and possesses a reddish yellow color. Vegetable wool is a product obtained from the green cones of the pine and fir by processes of fermentation, washing, and mechanical disintegration. It is used in mixtures with cotton and wool for the production of yarns, and also for the stuffing of mattresses, etc. The yarns prepared from vegetable wool mixed with sheep's wool are used in the manufacture of the so-called "hygienic flannels." * * These are especially recommended for gouty patients, as it is claimed they keep the body uniformly warm and protect it from dampness. CHAPTER XIV. ARTIFICIAL SILKS; LUSTRA-CELLULOSE. i. General Considerations. Owing to the high price and value of silk as a textile fibre, numerous attempts have been made to produce an artificial filament resembling it in properties.* Several of these processes have been attended with a considerable degree of success, and at the present time artificial silk has become a commercial article, and is used in considerable quantity by the textile trade. f The varieties of these silks divide themselves into the following classes: (1) Pyroxylin silks, made from a solution of guncotton in a mixture of alcohol and ether. (2) Fibres made from a solution of cellulose in ammoniacal copper oxide or chloride of zinc. (3) Viscose silk, made from a solution of cellulose thiocarbon- ate. (4) Gelatin silk, made from filaments of gelatin rendered insoluble by treatment with formaldehyde. With the exception of the last class, all of these so-called silks are filaments of cellulose, resolidified from various kinds of solu- * The entomologist Reaumur, in the year 1734, in a memoir on the history of insects, appears to have been the first to look forward to the possible preparation of silk by artificial means. It was not until 1884, however, that the first commer- cial process for the preparation of artificial silk was taken out in patent form by the Count Hilaire de Chardonnet. f The first attempt at the spinning of a solution of collodion appears to have been made by Audemars at Lausanne (Eng. Pat. 283 of 1855). Further experi- ments were made by Weston (Eng. Pat. of Sept. 12, 1882) and Swan (Ger. Pat. 30291 of 1884) on solutions of nitrated cellulose in acetic acid. Wynne-Powell (Eng. Pat. of Dec. 22, 1884) tried the preparation of filaments from a solution of cellulose in zinc chloride. All of these attempts had in viw the preparation of filaments for incandescent electric lamps. 55 256 THE TEXTILE FIBRES. tions, hence it has been proposed to give to these fibres the general name of lustra-cellulose, as one more descriptive of their true nature.* The large majority of the lustra-cellulose used in trade at the present time falls under the first class of pyroxylin silks. This represents the oldest and most successful method employed for the manufacture of this interesting fibre; and there are three chief processes by which the silk is made, known by the names of the respective inventors: Chardonnet, du Vivier, and Lehner. All of these processes use a solution of nitrated cellulose as a base, and employ the same general mechanical idea to produce the filaments of the fibre, the principle being to force a solution of nitrated cellulose through a fine capillary tube, coagulate the thin stream of solution thus obtained, and finally denitrate and reel the thread of filaments so obtained. As previously described (page 225), cellulose, on treatment with nitric acid, can be made to yield a series of nitrated celluloses, the exact compound obtained being dependent upon the conditions of treatment. 2. Chardonnet Silk. This is prepared from octonitrated cellulose dissolved in a mixture of alcohol and ether. f The * From the term "artificial silk," many would reasonably suppose that the substance so designated is the same in composition and nature as the fibre derived from the silkworm, but made by chemical or other artificial means. This is not the case, however, and the term "artificial silk" is rather a misleading one in this sense. The name in reality stands for a fibre resembling in its lustre and general appearance the true silk of nature; but the identity goes no further than this; for, in its chemical composition and properties, artificial silk is entirely distinct from that produced by the silkworm. It would be better to call the artificial product "imitation silk," or give it some name more distinctive of its origin and ^rue nature, such as the term "lustra-cellulose," proposed by Cross and Bevan. The latter term is especially adapted to the product in question, for the different varieties of this fibre which have acquired any degree of technical importance are all made from cellulose derivatives, and their chief quality is their high degree of lustre. t Many attempts have been made to reduce the cost of the collodion and to obtain other solvents for the nitrated cellulose. Bronnert in 1895 brought for- ward a process of making collodion, based on the solubility of tetranitrated-cellu- lose in alcoholic solutions of certain salts, such as calcium chloride, ammonium acetate, and ammonjum sulphocyanide. The explanations advanced for these reactions are rather uncertain. It may be supposed that the ammonium acetate produces a hydrolysis, the ammonium sulphocyanide a partial denitration of the ARTIFICIAL SILKS; LUSTRA-CELLULOSE. 257 solution is coagulated by passage through water, and is subse- quently denitrated * by a treatment with dilute nitric acid, chloride of iron, and ammonium phosphate. It forms a glossy, flexible fibre, possessing the peculiar feel and scroop of true silk. The pyroxylin employed for the production of Chardonnet's silk may be prepared from either wood-pulp, cotton, ramie, or FlG. 64. Chardonnet Silk. ( X 350.) (Micrograph by author.) other source of purified cellulose. As there are several nitrated compounds of cellulose soluble in the alcohol-ether mixture tetranitrated-cellulose, and the calcium chloride an alcoholic derivative of the cellulose, which could well be an ethoxy-derivative, if the opinion of Dr. Bron- nert, "that the body designated by the name of tetranitrated-cellulose is a tetra- nitrated-oxycellulose," is correct. The different compounds thus formed would be soluble in alcohol. (See Bernard, Mon. Scientij., May, 1905.) * When first prepared, pyroxylin silks were very inflammable, which led to their being regarded with disfavor. The processes of denitration, however, have now rendered them even less inflammable than ordinary cotton. Antiphlogin is the trade-name of a mixture used for the purpose of overcoming the inflammable nature of artificial silk. It consists of boric acid, phosphate of ammonia, and acetic acid. Pyroxylin steeped in this solution is said to be incombustible. 25 8 THE TEXTILE FIBRES. (which is employed as the pyroxylin solvent), and as it is difficult to obtain satisfactory separations of the individual compounds, it is probable that the pyroxylin contains penta-, tetra-, tri-, and di-nitrated cellulose, the tetra- and tri-nitrated compounds prob- ably occurring in larger amounts. The preparation of a pyrox- ylin, suitable for use in the making of Chardonnet silk, as pre- scribed by Wyss-Naef, calls for a nitrating mixture of 15 parts of fuming nitric acid (sp. gr. 1.52), with 85 parts of commercial sulphuric acid. For 4 kilograms of cellulose about 35 litres of this acid mixture are required, and the time of action is from four to six hours. Samples are examined from time to time with the micro-polariscope in order to ascertain the degree of nitra- tion, and when all the fibres appear of a uniform bright blue color under the polariscope the action of the acid mixture is discontinued. The excess of acid is removed from the fibre by means of a hydraulic press, after which the nitrated cellulose is washed for several hours with water and then pressed again, until the mass contains only about 30 per cent, of water. At first the pyroxylin so prepared was dried before being dissolved in the alcohol-ether solvent, but it was subsequently discovered that a better solution could be obtained by using the pyroxylin containing the amount of water above noted. This form of pyroxylin has been called by Chardonnet " pyroxylin hydrate," but it is doubtful if the substance is a true hydrate. However, it appears to be about 25 per cent, more soluble than the dry pyroxylin. The solvent employed for the pyroxylin consists of a mixture of 40 parts of 95 per cent, alcohol with 60 parts of ether, and 100 parts of this liquid will dissolve about 28 to 30 parts of pyroxylin. The collodion so produced is filtered several times under pressure, in order to free it from all non-nitrated and un- dissolved fibres, and to obtain a perfectly clear and homogeneous solution. This condition is a very essential one for the successful production of the silk, as any irregularity in the solution would cause a break in the continuity of the spun filament or a stoppage of the machine. The pyroxylin requires from 15 to 20 hours for complete solution, and that prepared from cotton requires a longer time to dissolve than that from wood-pulp. In order ARTIFICIAL SILKS; LUSTRA-CELLULOSE. 259 to properly filter the solution a pressure of 30 to 60 atmospheres is necessary. The next operation in the manufacture of the silk is purely a mechanical one, and yet one which has required the use of considerable ingenuity and skill.* The object is to force the collodion solution through very fine capillary glass tubes, so that it may be drawn thence as a fine continuous filament. The collodion solution is quite viscous, and requires a pressure of from 40 to 50 atmospheres to force it through capillaries of 0.08 mm. diameter. The flow of solution and pressure must be so adjusted and capable of regulation as to provide a uniform fila- ment, and this involved many mechanical difficulties, which were only overcome after long experimenting and numerous failures. We will not, however, at this point enter into a consideration of the various mechanical devices, ingenious though they are, which * An outline of the methods employed in the practical manufacture of Char- donnet silk is as follows: A good quality of wood-pulp is carefully disintegrated by suitable machines (resembling a carding-machine), so as to separate the indi- vidual fibres as much as possible. The bulky, fleece-like mass is then dried by steam heat at I40-i6o C., after which the heated fibres are steeped in a mix- ture of concentrated sulphuric and nitric acids, as in the general method of mak- ing gun-cotton. After suitable treatment in the acids, the nitrated cotton is centrifugated to remove excess of acid, then washed until it contains only about 10 per cent, of acid. The product was formerly dried in special drying-rooms, where the temperature should not be above 30 C., and every precaution must be taken to avoid explosions. The dried nitrated cellulose was then dissolved in a mixture of equal parts of alcohol and ether, so as to secure a 20 per cent, solution. The resulting collodion (as the solution is now known) is carefully filtered through silk sieves in such a manner as to remove all undissolved fibres or other foreign matter. The collodion then passes to the spinning-machine where it is forced through tubes having nozzles of glass or platinum with fine orifices. As the threads of collodion appear they come into immediate contact with a fine stream of water, which removes the solvent and coagulates the cellulose compound. Several of the fine threads are united and are wound on bobbins and into suitable hanks. The silk is then denitrated by treatment with a warm solution of ammonium sulphide, after which the hanks are washed and slightly acidified in order to remove all the ammonium compounds. The process of denitration causes the silk to lose about 40 per cent, in weight, though this is usually replaced in part by proper impregnation with solutions of metallic salts, which also have the effect of making the silk fire-proof. In the manufacture of collodion silk, an important factor is the recovery of the solvent from the wash -waters; owing to the extreme volatility of the ether this is by no means an easy task. 260 THE TEXTILE FIBRES. have been perfected for the proper spinning and handling of this artificial fibre.* The thread as it emerges from the capillary tube is rapidly coagulated in the air by the evaporation of the solvent. By suitable arrangement of a hood over the machine and condensing chambers in connection therewith, a large portion of the mixed volatile vapors of the alcohol and ether employed as the solvent are condensed and collected, thus effecting a considerable saving in the amount of solvent required, and also minimizing the danger of explosions occurring. Several of the individual filaments are brought together into a single thread and wound on spools in the manner of ordinary silk. In this operation a certain amount of adhesion takes place between the separate filaments, which considerably enhances the ultimate strength of the finished thread. The thread in this form now consists of pyroxylin or nitrated cellulose, and is highly inflammable and otherwise unsuitable for use in textile fibres. The next operation through which it passes is one for the purpose of denitrating the cellulose, in order that the fibre may ultimately consist of what might be termed " regenerated " cellulose, the exact chemical nature of which it is not possible to definitely state, though it is evidently some form of cellulose. The denitration is accomplished by passing the pyroxylin threads through a bath of ammonium sulphide, though other alkaline sulphides, and various other compounds also, will effect the same result. The silk in this con- dition has a rather yellow color, which, however, may be bleached out in the usual manner with a solution of chloride of lime. The fibre, as finally obtained, possesses a very high lustre, though it is somewhat metallic in appearance; it has considerable tensile strength, though in this respect, as also in elasticity, it is consider- ably below true silk. The fibre is also rather harsh and brittle, and does not possess the softness and resiliency of natural silk.f 3. Du Vivier's Silk. The basis of du Vivier's silk is a solution of trinitrated cellulose in glacial acetic acid. In practice, * See Silvern, Die kunstliche Seide, Berlin, 1900, and Williams, La Soie Arti- ficielle, Paris, 1902. f See Matthews, Jour. Soc. Chem. Ind.. 1904, p. 176. ARTIFICIAL SILKS; LUSTRA-CELLULOSE. 261 this is mixed with a solution of gutta-percha in carbon disulphide, and one of isinglass in glacial acetic acid. Small quantities of glycerol and castor-oil are added, and the mixture is drawn through the spinning-tubes into water, where it becomes coagu- lated. The thread which is so formed is treated successively with soda, albumin, mercuric chloride, and carbon dioxide. Du Vivier's silk is hard, and very white arid glossy. 4. Lehner's Silk. Lehner employs a solution of nitrated cellulose in ether and methyl alcohol, to which he adds a solution of natural silk in glacial acetic acid.* The thread is coagulated by passage through a mixture of turpentine, chloroform, and juniper-oil, and is afterwards treated with a solution of sodium acetate.f Silk-like filaments may be obtained from a solution of cellulose in zinc chloride. The liquid may be easily spun, but the thread which is formed is too weak to be employed as a substitute for silk. The solution is principally used for the manufacture of filaments for incandescent electric lamps. A better solution is obtained by using alkali-cellulose in place of cellulose (Bron- nert) . * Lehner's silk is now produced by much the same means as that of Char- donnet, and the fibre is very similar to that of the latter. Lehner at first attempted to obtain a fibre from a mixture of pyroxylin solution with various vegetable gums and oils, with solutions of cotton in copper-ammonium sulphate, and even with solutions of waste silk itself. None of these, however, proved a success, and he reverted to the more simple solution of pyroxylin in combination with a drying oil. He also discovered that the fluidity of the collodion could be materially enhanced by the addition of sulphuric acid, and consequently he was able to work his solution under much less pressure than Chardonnet. fThe manufacture of artificial silk has of late years become an enterprise of commercial importance. There are factories producing pyroxylin silk at Besanfon (France), Spreitenbach and Zurich (Switzerland), Wobton (England) ,, and Elberfeld (Germany). The fibres are formed by forcing the ether-alcohol solution of pyroxylin through glass capillary tubes and winding them on frames. As the solution is very viscous, it requires a pressure of 45 atmospheres to dis- charge it through the capillary openings. It was formerly the custom to carry out the dyeing of pyroxylin silk in the pulp, but this proved to be impracticable, and at present it is chiefly dyed in the form of yarn. The proportion between the price of natural and artificial silk is approximately as follows- Natural silk, $10 per kilogram; pyroxylin silk, $475 per kilogram; gelatin silk (vanduara), $2.40 per kilogram. 262 THE TEXTILE FIBRES. A solution of cellulose sulphate in caustic soda may be used for the making of artificial silk. The following method is said to be capable of yielding good results: 10 parts of cotton are mixed with 100 parts of sulphuric acid of 1.55 sp. gr., the mass is thrown into water, and the precipitated cellulose sulphate is washed, and then dissolved in 100 parts of caustic soda of 1.12 sp. gr.* This FIG. 65. Cuprammonium or Pauly Silk. (X35Q.) (Micrograph by author.) solution is spun in the usual manner, and the thread is subsequently coagulated. 5. Cuprammonium Silk. Lustra-cellulose threads are also prepared from a solution of cellulose in ammoniacal copper oxide solution (Schweitzer's solution). f The process in brief * Vereinigte Kunstseidefabriken of Frankfurt. fWeston, in 1884, used this solution for the making of incandescent-lamp filaments; Despeissis, in 1890, first thought of applying it to the preparation of artificial silks. Fremery and Urban, in 1897, under the name of Pauly, patented the first practical process for the manufacture of the fibre. This silk is now made in considerable quantity by the Vereinigte Glanzstoff-fabriken Actiengesellschaft of Aachen, who have factories at Oberbruch and Niedermorschweiler. The product is known as Pauly' ] s silk or Parisian artificial silk. ARTIFICIAL SILKS; LUSTRA-CELLULOSE. 263 is as follows: The copper solution is first prepared by treating copper turnings with ammonia in the presence of lactic acid at a temperature of 4 to 6 C. At the end of about ten days the intense blue solution of ammoniacal copper oxide is ready for use. The next step is to obtain mercerized cellulose (cellulose hydrate),* which is done by mixing 100 parts of cellulose with 1000 parts of a solution containing 30 parts of sodium carbonate and 50 parts of caustic soda. This mixture is heated for 3^ hours in a closed vessel under a pressure of 2^ atmospheres. The mercerized cotton thus obtained is washed, dried, bleached with chloride of lime, washed and again dried; after which it is dissolved in the ammoniacal copper oxide solution. The solution (containing 7 to 8 per cent, of mercerized cotton) is filtered, settled, and then spun through capillary tubes under a pressure of 2 to 4 atmospheres. The thread is coagulated by passing through a bath containing 30 to 65 per cent, of sulphuric acid. 6. Viscose Silk. This is prepared from solutions of cellulose thiocarbonate. It has been made with some degree of commercial success in the United States and Europe. It is principally made in coarse numbers, and is used as an artificial horse-hair. Finer numbers of considerable softness have also been made, for use in braids, passementerie, etc. Viscose itself is prepared by the action of caustic alkali and carbon disulphide on mercerized cellulose, a gelatinous mass being obtained which is readily soluble in water, giving a yellowish and very viscous solution. Viscose is an alkaline xanthate of cellulose, and its industrial manufacture is carried out in the following general manner : Sheets of crude wood-pulp are ground up with solid caustic soda in a circular-edge roller-mill until a finely divided crumb-like mass is obtained. The product in this form is known as " crumbs," and consists of alkali-cellulose. The excess of moisture is then pressed out, and the material is * Ordinary cellulose dissolves but very slowly in Schweitzer's reagent, and moreover the solution is always accompanied by oxidation which changes the cellulose molecule so that it is not fit to spin. Bronnert first proposed the use of cellulose hydrate, and so made the method of practical value. 264 THE TEXTILE FIBRES. allowed to lie for some time. This alkali-cellulose is then placed in a vat provided with a rotary stirrer, where it is treated with carbon disulphide. The resulting mass is translucent and gelatinous in appearance and of a clear brown color, and is known by the name of viscose. Immediately after its formation, the viscose is dissolved in water and then filtered in order to remove any cellulose fibre which may not have undergone chemical FIG. 66. Viscose Silk. (X35Q.) (Micrograph by author.) transformation. For the successful preparation of artificial silk it is necessary that the filtering should be as perfect as pos- sible, for the occurrence of any fibres in the solution will cause stoppages of the spinnerets and consequently breaks in the filaments. After filtering the viscose solution is thoroughly mixed. When the desired degree of fluidity has been attained (which is indicated by means of a viscosimeter), the viscose solu- tion is run into suitable reservoirs, in which it is maintained at a temperature of 32 F. Previous to passing into the spinning- machines, the viscose solution is filtered a second time, after ARTIFICIAL SILKS; LUSTRA CELLULOSE. 265 which it is run into an apparatus where it is subjected to high pressure for the purpose of forcing out all air-bubbles which are liable to be retained by the viscous solution. This latter treat- ment is very essential, as the presence of air-bubbles would interfere very materially with the regularity of the spun fibre. The viscose solution then goes into an apparatus which may be called a spinning-frame. This consists of a double series of small pumps, which force the solution through platinum spin- nerets pierced with very fine openings, the number of which varies with the size of the thread it is desired to produce. The production, therefore, is proportional to the number of orifices in use; the normal number being about eighteen orifices per thread, while each orifice corresponds to a daily production of about 28 grams (about one ounce). Each spinneret and tube which carries it are immersed in a concentrated solution of ammonium sulphate, for the purpose of coagulating the liquid jet coming from the spinneret by bringing it into immediate contact with the solution. The different filaments forming the threads are at the same time united into one single fibre, and these are carried into a solution of ferrous sulphate (copperas) in order to remove all residual matter left on the fibre from the first bath. The threads then pass into a turbine bobbin, which collects them into skeins, and at the same time gives the thread the desired degree of twist. The fibre, in the form of hanks, is then steeped in an acid solution for the purpose of neutralizing any alkali left in the filaments, the excess of acid being afterwards removed by washing in water. The fibre at this stage has a rather pro- nounced yellow color, which is removed by bleaching with chloride of lime. Viscose silk has a fine glossy appearance, and possesses a tensile strength about equal to that of pyroxylin silk; like the latter, however, it is also weakened when moistened with water. 7. Properties of Lustra-cellulose. The chief drawback to the commercial success of collodion silk is its behavior with water. When wetted the fibre loses its original strength to such a degree that it must be handled with great care. Soap solutions and dilute acids have no injurious effect, but alkaline solutions rapidly disintegrate the fibre and finally dissolve it completely. The 266 THE TEXTILE FIBRES. material is difficult to dye, on account of the weakening action of water, and the operation must be carried out with great care. The dyeing is accomplished without the addition of either soap or acid to the bath. The basic coloring-matters and some of the direct cotton colors appear to be the best dyestufls to employ. Besides the three processes already given % of obtaining collo- dion silk, there are other methods for the manufacture of this artificial product. Langhaus * employs as a raw material a prep- aration from cellulose and sulphuric acid. Cadarat uses nitrated cellulose, dissolving it in a very complex mixture of glacial acetic acid, ether, acetone, alcohol, toluol, camphor, and castor-oil. This forms a plastic mass which is treated with some proteid substance, such as gelatin or albumin dissolved in glacial acetic acid. After spinning the fibres are treated with tannin in order to render them elastic. Hoepfner f has prepared porous acid-proof fabrics to be employed for filtering purposes in electrolytic work by using cot- ton yarn which has been nitrated. The latter can be woven along with asbestos, glass, or other mineral fibres in the making of the fabric. If nitrated cotton be examined under the microscope, a con- siderable alteration in its appearance will be observed. The fibres have a much thicker cell- wall, and are consequently stiffer than those of ordinary cotton. The lumen has either vanished entirely or become very much contracted, and this appears to be due to the swelling of the cell- walls. In the w r alls of the fibre there will also be noticed numerous fractures or cracks which often assume a spiral shape. The nitration has evidently rendered the fibre much more brittle and has decreased its elasticity. Solutions of nitrated cellulose have been employed for a number of purposes, such as the production of films for photo- graphic use, the manufacture of lacquers, etc. The author has * This process consists in dissolving cellulose in a mixture of concentrated sulphuric acid and phosphoric acid, and treating the syrup so obtained with glyceric ether or ethyl ether. The silk obtained by this process is not of good quality, and the solution is not very stable, as it soon precipitates more or less altered cellulose. f Farber-ZeiL, 1897, No. 5. ARTIFICIAL SILKS; LUSTRA-CELLULOSE. 267 also successfully utilized such a preparation for the waterproofing of paper and other materials. It also forms an excellent water- proof sizing and stiffening agent for all manner of textile fabrics and hats. As the solutions of nitrated cellulose possess great viscosity, it is difficult to prepare a very concentrated solution. The addition of formaldehyde or benzol, however, to the ordinary solvents, will increase the dissolving capacity considerably, and also give a more mobile solution. Epichlor- and dichlorhydrins also act as excellent solvents for nitrated cellulose, being capable of dissolving it in any proportion. The acetate of cellulose (see p. 220) has also been used as a basis for the manufacture of artificial silk. It is dissolved in a suitable solvent and spun in the same manner as collodion silk, the thread being coagulated by passing through a bath of water. With collodion silk the weight of the product obtained (after denitration) is scarcely equal to that of the cellulose used, whereas with acetyl cellulose the weight of the resulting silk corresponds to about twice the weight of the cellulose taken. The silk made from acetyl cellulose, however, is less stable towards acids and alkalies than collodion silk, neither does it dye as readily; and the dyeing is best done by adding the coloring-matter to the solution before spinning. The silk made from acetyl cellulose is known as " cellestion " silk, and is much used for covering electric wires, as it has remarkable insulating properties. 8. Vanduara Silk.* This is a thread of gelatin, and conse- quently differs from the other artificial silks in that it consists of animal tissue and not vegetable. Due to this circumstance, it has more analogy chemically to true silk than the various cellulose silks. The manufacture of vanduara silk is conducted by forcing an aqueous solution of gelatin through a fine capillary tube; the thread so produced is carried on an endless band through a drying-chamber. The soft gelatin thread, of course, flattens out considerably during this operation, hence the silk * Vanduara silk is an English invention, the patentee being Adam Millar. The silk has never appeared on the market as a commercial commodity, and the process does not seem to have met with any marked degree of success. 268 THE TEXTILE FIBRES. eventually forms a flat, ribbon-like fibre. After drying and properly reeling the fibre is treated with vapor of formaldehyde, which causes the gelatin to become insoluble in water. By vary- ing the pressure on the gelatin solution, whereby it is forced through the capillary tube, the thickness of the fibre may be increased or diminished. The same result may be attained by varying the speed of the endless band which carries the thread after coming from the capillary tube. The silk may be dyed either in the ordinary way in skein form after reeling, or the gelatin solution may be colored before the thread is drawn out. The fibre is very lustrous, and if the filaments are drawn fine enough the silk is soft and pliable. 9. Comparison of Artificial Silks. Hassac * gives a com- parison of several makes of artificial silk. Chardonnet's and Lehner's silks are very similar in appearance; they are more lustrous than real silk, but are stifler, and do not possess the characteristic feel. Cellulose silk made by Pauly's ammoniacal copper oxide process is similar to the former in appearance, but its lustre is even better, and it has the characteristic feel of true silk. Lehner's silk under the microscope is characterized by deep longitudinal grooves and small air-bubbles; its cross- section is highly irregular. Pauly's silk shows fine longitudinal grooves and minute transverse lines in the centre of the fibres; its cross-section is regular, approaching a circle or ellipse. Ham- mel's gelatin silk is almost circular in outline, and is free from grooves and bubbles; in polarized light it is singly refracting, while the others are doubly so. As the collodion silks always contain some nitrated compound, they give a blue color with dipheDvlamin and sulphuric acid. Water causes all the artificial silks to swell, while alcohol or glycerol contracts them. In strong sulphuric acid the collodion silks swell rapidly and dissolve; Pauly's cellulose silk gradually becomes thinner and dissolves; gelatin silk only dissolves on strong heating. Chromic acid dissolves all artificial silks in the cold ; real silk dissolves but slowly, while cotton and other vege- table fibres are unaffected. Caustic potash does not dissolve * Chem. ZeiL, 1900, pp. 235, 267, 297. ARTIFICIAL SILKS; LUSTRA-CELLULOSE. 269 the collodion or cellulose silks, but both the gelatin silk and real silk are soluble on boiling. Schweitzer's reagent dissolves collodion and cellulose silks; whereas gelatin silk is insoluble, but stains the liquid a bright violet. Alkaline copper-glycerol solu- tion at 80 C. dissolves real silk immediately. Tussah and gelatin silks dissolve when boiled for one minute; the other silks are not affected. lodin solution colors artificial silks an intense red, which changes to a transient pale blue on washing with water in the case of collodion silks, though cellulose silk does not show this blue color. lodin and sulphuric acid stain true silk a yellow color, gelatin silk brown, while collodion and cellulose silks are colored blue. COMPARISON OF DIFFERENT ARTIFICIAL SILKS WITH REAL SILK (HASSAC). Moisture. - Fibres to Sq. Mm. Tens. Strength. Kilo, per Sq. Mm. El as- % q n ri r Silk. Per Ct. Air- Satu- dry, Par Ct. rated, Per Ct. Wet. Dry. Wet. Dry. Real silk 8 71 20 1 1 I ?6 Q7IO O7IO 37 O 27 O 21 6 Chardonnet II II 27 46 I ^2 6dO 1 1 -if oi - w 2 2 01 ' v 12 O 8 o (Walston) 11.32 28.94 J -53 683 1620 I.O 22.3 7-9 Lehner 10 4: 26 45 i ^i 4.1-2 1180 I 16 o 7 ? Pauly o. 20 23.08 I . SO 742 ICCQ 7 2 10 I / -o 12 ? Gelatin 13.98 45 -5 6 i-73 265 945 O.O 6.6 3-8 Strehlenert and Westergren give the following figures for the tensile strengths of various natural and artificial silks. The figures indicate the breaking strains in kilograms per square millimetre section: NATURAL SILKS. Dry. Wet. Chinese silk 53.2 46. 7 French raw silk 50.4 40.9 French silk, boiled off 25 . 5 13.6 " " dyed red and weighted 20.0 15.6 " " blue-black, weighted 110% 12.1 8.0 " " black, weighted 140% 7.9 6.3 '* " black, weighted 500% 2.2 270 THE TEXTILE FIBRES. ARTIFICIAL SILKS. Dry. Wet. Chardonnet's collodion, undyed 14. 7 1.7 Lehner's collodion, undyed 17.1 4.3 Strehlenert's collodion, undyed 15 - 9 3-6 Pauly's cuprammonium, undyed 19.1 3.2 Viscose silk, early samples 11.4 3.5 ' ' ' ' latest samples 21,5 Cotton yarn (for comparison) 11.5 18.6 10. Animalized Cotton. Cotton may be " animalized " that is, given the dyeing properties possessed by animal fibres in a variety of ways. The material may be impregnated with albumin and afterwards steamed; this method is employed to some extent in printing, being used chiefly in connection with the direct cotton colors to prevent their bleeding. A solution of casein may also be used instead of albumin, with similar results. The same property may also be imparted to cotton by treatment with tannic acid and gelatin or lanuginic acid (solution of wool in caustic alkali), but with doubtful results; though Knecht describes a method which is said to give satisfaction, the cotton being impregnated with a solution of lanuginic acid and allowed to dry in the presence of formaldehyde, when the fibre becomes coated with an insoluble film possessing a remarkable affinity for the substantive dyes. Vignon claims that by treating cotton under pressure with ammonia in presence of zinc chloride or calcium chloride, the fibre acquires an increased affinity for the basic and acid dyestuffs. His results, however, have not been confirmed. A silk-like appearance may also be given to vegetable fibres by treatment with a solution of silk (fibroin) in some suitable solvent, such as hydrochloric, phosphoric, or sulphuric acid, or cupram- monium, etc. The silk employed is made up of scraps and waste which would otherwise be useless. Better results are obtained if the cotton material be treated with a metallic or tannic acid mordant before immersion in the silk solution, and should after- wards be calendered and polished in order to obtain a glossy appearance. CHAPTER XV. LINEN. i. Preparation. Linen is the fibre obtained from the flax plant, botanically known as Linum usitatissimum* The fibre is prepared from the bast of the plant by a process called retting, - which has for its purpose the separation of the fibrous cellulose / from the woody tissue and other plant membranes. Historically linen appears to have been the earliest vegetable fibre employed in- dustrially^ having been used at a much earlier date than cotton. Though grown more or less in every country, { at present the cultivation of flax is principally carried on in France, Ireland, Belgium, Holland, Russia, United States, and Canada. || The * Botanists recognize upwards of one hundred species of the flax plant, but, of all these, the only one possessing industrial importance and the only one readily cultivated is the Linum usitatissimum (or L. commun), which has a blue flower. The North American Indians have long used the fibre of L. luvisii, which differs from the ordinary cultivated flax in having three stems growing from a perennial root. The most ancient species of flax brought under cultivation is thought to be L. an gusti folium; the Swiss lake-dwellers are said to have grown it, as also the ancient inhabitants of northern Italy. The flax cultivated in the eastern coun- tries, in Assyria and Egypt, appears to have been the common variety L. usitatissi- t Egyptian linen fabrics (mummy-cloths) have been found which are probably over 4500 years old. | The world's annual production of linen is about 1,000,000,000 pounds. Only in the vicinity of Yale, Michigan, at Northfield and Heron Lake, Minne- sota, and at Salem and Scio, Oregon, is flax cultivated in America for the production of spinning fibre. In all these localities the seed is saved, and it is doubtful if the industry would yield sufficient profits from the production of the fibre alone to warrant its continuance under present conditions. (Yearbook, Dept. Agric., 1903.) || The Department of Agriculture gives the following marks of the commercial grades of flax imported into the United States : From Russia: Russian flax is known either as Slanetz (dew-retted) or Mot- clwnetz (water -retted) ; ungraded fibre is called Siretz. The latter comes chiefly 271 272 THE TEXTILE FIBRES. bast tissue, which is used for the fibre, is situated between the bark and the underlying woody tissue (see Fig. 68). The flax plant, is annual in growth and rather delicate in structure. It grows to about 40 inches in height ; the stem is slen- der, branching only slightly at the top, and bears naked, lanceo- late, alternate leaves. The flower is mostly sky-blue, though some- times white ; the seed-capsules are five-lobed and globular, and of the size of peas. The flax plant, after attaining its proper growth, is either cut down or pulled up by its roots, and subjected to a process tech- nically known as rippling, the plants being drawn through a machine consisting of upright forks which remove the seeds and leaves.* The remaining stalks are then tied in bundles from St. Petersburg, and is known under the names of Bejedsk, Krasnoholm, Troer, Kashin, Gospodsky, Nerechta, Wologda, Jaraslav, Graesowetz, and Kos- troma; all these varieties are slanetz. Pochochon, Ouglitz, Rjeff, Jaropol, and Stepurin are motchenetz. From Archangel are brought slanetz varieties known as First Crown, Second Crown, Third Crown, Fourth Crown, First Zabrack and Second Zabrack. From Riga are obtained motchenetz varieties graded from the standard mark K through HK, PK, HPK, SPK, HSPK, ZK, GZK, and HZK. From Holland: Dutch flax is graded by the marks ^, ^, VI, VII, VIII, IX. From Belgium: Flemish flax (or blue flax) includes Bruges, Thisselt, Ghent, Lokeren, and St. Nicholas, and is graded as ^, ^ ^, VI, VII, VIII, IX. Cour- trai flax is graded as ~ j5- .-L, -- ^, I, VI. Furnes and Bergues flax is graded A, B, C, D. Walloon flax is graded II, III, IV. Zealand flax is graded IX, VIII, VII, VI. Friesland flax is graded D, E, Ex, F, Fx, Fxx, G, Gx, Gxx, Gxxx. From France: French flax is known by the districts of Wavrin, Flines, Douai, Hazebrouck, Picardy, and Harnes. From Ireland: Irish flax comes as scutched and mill scutched, and is known by the names of the counties in which it is raised. From Canada : This flax has no standard of marks or qualities. * Besides being cultivated for its fibre, the flax plant is also grown for its seed, which yields the valuable oil known as linseed. It possesses good drying quali- ties, and hence is extensively used for the preparation of paints and varnishes. The best seed-flax is grown in tropical and subtropical countries, whereas the best fibre-flax is grown in more northern climates. The seed obtained from the latter variety, though utilized as a by-product, produces only an inferior grade of oil. The oil-cake left after expressing the oil from the seed is an excellent cattle-food and is largely used for this purpose. LINEN. 273 and placed in stagnant water, where they are allowed to re- main for a number of days. Active fermentation soon starts, resulting in the decomposition of the woody tissues enclosing the cellulose fibres. When the proc- ess has gone sufficiently far, the bundles of fermented stalks are removed and passed through a number of mechanical operations, whereby the decomposed tissues are removed and the linen fibres are isolated in a purified condi- tion. This method of retting with stagnant water is known as " pool-retting." As the fermen- tation causes the evolution of considerable gas, in order to keep the bundles of stalks submerged, they are loaded with stones or boards. The time of steeping in the water varies with circum- stances from five to ten days.* Another method of retting is to steep in running water. The famous Courtrai flax of Belgium is retted in this manner in the river Lys. The flax- straw, after FlG - 67. -The Ancient Flax Plant, , , . Linum aneustiiolium. pulling, is placed in crates and (Aftcr Bulletin ^ s Dept Agric } submerged in the water of this stream for a period of four to fifteen days, depending on the * Dodge gives the following notes relative to the retting of flax: "For dew- retting a moist meadow is the proper place, the fibre being spread over the ground in straight rows at the rate of a ton to an acre. If laid about the ist of October and the weather is good, a couple of weeks will suffice for the proper separation of the fibre and woody matter. For pool -retting the softest water gives the best results, and where a natural pool is not available, such as the bog-holes' in Ireland, 'steep pools' will have to be built. A pool 30 feet long, 10 feet wide, and 4 feet deep will suffice for an acre of flax. Spring water should be avoided, or, if used, 274 THE TEXTILE FIBRES. temperature and other conditions. Courtrai flax is of a creamy color, whereas pool-retted flax has a rather dark bluish brown . f / FlG. 68. Cross-section of Flax-straw. A, layer of cuticular cells; B, interme- diate layer of cortical parenchym; C, bast fibres in groups, being the flax fibres proper (note secondary thickening of cell-walls); D, cambium layer; E, woody tissue. (Cross and Bevan.) the pool should be filled some weeks before the flax is ready for it, in order to soften the water. It should be kept free from all mineral and vegetable impuri- ties. The sheaves are packed loosely in the pool. . . . Fermentation is shown by the turbidity of the water and by bubbles of gas. ... If possible, the thick scum which forms on the surface should be removed by allowing a slight stream of water to flow over the pool. The fibre sinks when decomposition has been carried to the proper point, though this is not always a sure indication that it is just right to take out. In Holland, the plan is to take a number of stalks of aver- age fineness, which are broken in two places a few inches apart. If the woody portion or core pulls out easily, leaving the fibre intact, it is ready to come out. The operation usually requires from five to ten days." LINEN. 275 color. The excellent qualities of the Courtrai flax are said to be due to the action of the soft, slowly running, almost sluggish waters of the river Lys, and to the peculiar ferment existing therein. Another method employed for obtaining the fibre from flax is known as dew-retting, as the flax-straw is spread out in a field and exposed for a couple of weeks to the action of the dew and the sun. Dew-retting, however, gives the most un- ''*, ij ! jC I . i ! \ , y ii" \ ! : \pfi FIG. 69. Flax Fibres. (X40O.) a, a', cross-sections; b, longitudinal views; c, ends. (After Cross and Bevan.) even and least valuable product of the three methods employed, and the fibre is rather dark in color. There have also been several chemical methods proposed for retting flax, such as heat- ing with water under pressure, boiling with solutions of oxalic acid, soda ash, caustic soda, etc. None of these, however, have proved of any industrial value, and the older natural methods are still adhered to. Additions of various chemicals to the retting waters have at times proved of value, hydrochloric or sulphuric acid sometimes being used to advantage.* The intercellular substance holding the flax fibres together * Schenk's method of retting is to steep in warm water, a constant temperature of 35 C. being maintained. It is said that the fermentation may be completed by this method in fifty to sixty hours, and gives a larger yield and a better product than the natural processes of retting. In steam-retting, the bundles of flax-straw are placed in iron cylinders and heated with live steam or hot water under pressure, but the process does not appear to be successful. 276 THE TEXTILE FIBRES. consists mostly of calcium pectate, and the real object of retting is to render this substance soluble, so that it may be removed by the after-processes of treatment. Winogradsky has succeeded in isolating the particular organism * that is the active, agent in the pectin fermentation. f It is an anaerobic bacillus which readily ferments pectin matters, but has no action on cellulose. J By adding salts promoting the growth of the bacillus to the water employed in retting, it has been found possible to reduce the time of retting very considerably. It has been claimed that fatty acids exert a solvent action on the resinous and pectin mat- ters present in vegetable fibres, and a method for the decortication of flax and other bast fibres has been devised as follows: The * This organism is the Bacillus amylobacter . t The substances classified in a general way as "pectin matters" form the inter- cellular matter between the elemental cells of the bast fibres, and serve the purpose of a cementing medium to hold the small elements of the fibre together. Their character is that of a resinous gum- By certain investigators this resinous matter has been given the name pectose.\ It is hardly likely, however, that this substance consists of a single chemical compound, but it is more probably a mixture of several chemical individuals. By heating with dilute acid, pectose is converted into a series of products which have received considerable attention from botanical chemists; the products include pectin, para-pectin, meta-pectin, pectosic acid, pectic acid, para- pectic acid, meta-pectic acid, etc. Pectin and especially para- and meta-pectin are soluble in water, whereas pectic acid is not. Therefore, if it is desirable to sepa- rate the elements of a vegetable tissue, it is necessary to stop the action of the retting agents before the formation of pectic acid. In the case of the preparation of linen, however, it appears to be necessary not to dissolve out all the pectose de- rivatives from the fibre, but to allow of the formation of some pectic acid, as this makes the surface of the fibre more brilliant (Lecomte, Textiles leg&aux) and leaves it stronger and more elastic. J The water-retting of flax is a biological process induced by the action of definite organisms, the chief of which is an anaerobic Plectridtttm, which in the absence of air ferments the pectin substances of the cellular material uniting the parenchymous tissues, and thus causes a loosening of the bast fibres. The exclusion of oxygen, which is necessary that the fermentation may be set up,' is brought about by numerous oxygen-consuming bacteria and fungi. The prod- ucts formed by the fermentation of the pectin substances are hydrogen and carbon dioxide and organic acids, especially acetic and butyric and small quantities of valeric and lactic acids. The injurious action of the acids produced, especially butyric acid, may be considerably diminished by adding alkali or lime to the retting liquid. It is also advantageous to inoculate the liquid at the beginning of the retting with pure cultures of the anaerobic Plectridium. (See Stormer, Chem. Centr., 1905, p. 41.) LINEN. 277 raw fibres are impregnated with boiling soap solutions, after which ammonium chloride is added, which liberates the fatty acids. After several hours' treatment these dissolve all gummy and resinous matters; the fibres are then treated with weak caustic alkali, after which they are washed and dried, when they should be thor- oughly disintegrated. Good results are said to be obtained by this method. The flax stalks, after being deprived of their leaves and seeds by rippling, are known as flax- straw. The latter in the air-dry condition con- tains from 73 to 80 per cent, of wood, marrow, and bark, and 20 to 27 per cent, of bast. The general structure of flax-straw, and of bast stalks in general, is shown in the schematic drawing (Fig. 70). The linen fibre as it is obtained from the plant and as it appears in trade js in the form of filaments, the length * of which varies con- siderably with the manner and care employed in decorticating, and may be from a few inches to several feet.f These filaments are composed structurally of small elements or cells, consisting of practically pure cellulose. They are uniformly thick, and average 12 to 25 /* in diameter and 25 to 30 mm. in length. Their structure is rather regular, oeing cylindrical in shape, though somewhat polygonal in cross- Fic.70. Diagram of Flax-straw, i, marrow; 2, woody fibre; 3, cambium layer; 4, bast fibre; 5, rind - or .bark. (After Witt.) * Flax fibre is from 12 to 36 inches in length, silvery gray when dew-retted, yellowish white when water-retted, capable of fine subdivision, soft and flexible, and is the strongest of the fine commercial bast fibres. It is used for making linen sewing thread, shoe thread, bookbinders' thread, fishing-lines, seine twine, the better grades of wrapping twine, and knit underwear, and for weaving into handkerchiefs, towelling, table-linen, collars and cuffs, shirt-bosoms, and dress- goods. The finer grades of linen damasks are imported, as the weaving of these goods is slow work, and requires a kind of labor not commonly found in this coun- try. (Yearbook, Dept. Agric., 1903.) f Good flax should average 20 inches in length and be free from fibres less than 12 inches in length. s 21% THE TEXTILE FIBRES. section. A peculiarity in the appearance of the cells is the occurrence of faintly marked " dislocations " or so-called " nodes " extending transversely and often in the form of an "X." These nodes may be made more apparent by stain- ing with methyl violet or chlor-iodide of ?inc solution. The cell-wall is quite uniform in thickness, and the lumen or internal canal is very narrow, and often is but faintly apparent as a dark line. The cross-section of the linen fibre shows no yellow cir- cumferential stain when treated with sulphuric acid, though the lumen shows up as a yellow spot. Wiesner gives the following dimensions of several varieties of flax filaments : * Kind of Flax. Mean Length of the Purified Flax Fibre, mm. Mean Breadth, mm. EizvDtian 060 O. 2ZZ Westphalian Belgian Courtrai Austrian 75 37 4.IO 0.114 o. 105 o 202 Prussian 280 o no 2. Chemical and Physical Properties. The flax fibre appears to consist of pure cellulose f and shows no signs at all of being lignified. It becomes strongly swollen by treatment with * Dodge gives the following dimensions for the elements of the flax fibre: Length, 0.157 to 2.598 inches; mean, about i inch; diameter, 0.006 to 0.00148 inch; mean, o.ooi inch. f In order to isolate pure flax cellulose, Cross and Bevan have recommended the following procedure: The non-cellulosic constituents of flax are pectic com- pounds which are soluble in boiling alkaline solutions. The proportion of such constituents varies from 14 to 33 per cent, in different varieties of flax. They may be completely extracted by first boiling the fibre in a dilute solution of caustic soda (i to 2 per cent.); the residue will consist of flax cellulose, with small rem- nants of woody and cuticular tissue, together with some of the oils and waxes associated with the latter. By treatment with a weak solution of chloride of lime, the woody tissue is decomposed, and is then removed by again boiling in dilute alkali. The remaining cellulose is then further purified from residual fatty and waxy matters by boiling with alcohol and finally with ether-alcohol mixture. Flax -cellulose prepared in this manner appears to be chemically indistinguishable from cotton cellulose. \ LINEN. 279 Schweitzer's reagent (see Fig. 71), but, unlike cotton, it does not completely dissolve therein.* The color of the best varieties of flax is a pale yellowish white. Flax retted by means of stagnant water, or by dew, is a steel gray, and Egyptian flax is a pearl gray. The pale yellow color of flax is due to a natural pigment, but the other color arises from the decomposition of the intercellular matter, which is left as a stain on the fibre. Flax that has been imperfectly retted shows a FIG. 71. Cell of Flax Fibre Treated with Schweitzer's Reagent. (X4oo.) Showing insoluble cuticle of inner canal. (After Wiesner.) greenish color. The natural color of linen is readily bleached by solutions of chloride of lime in a manner similar to the bleach- ing of cotton. But the linen fibre suffers considerable deteriora- tion thereby. There are four grades of linen-bleaching quar- ter, half, three-quarters, and full bleach. The whiter the fibre is bleached the weaker it becomes. f The lustre of linen is quite pronounced and almost silky in appearance; flax that is over- retted is dull in appearance. Egyptian flax is also dull, due to the cells being coated with residual intercellular matter. The flax fibre is much stronger than that of cotton, though overretted flax is brittle and weak.f * In swelling the fibre blisters considerably, but not in as regular a manner as cotton. The inner layers of the cell withstand the action of the reagent the longest and remain floating in the liquid, like the cuticle of cotton. Parenchymous and intercellular matter adhering to the fibre also remains undissolved in the reagent. f In determining the size (or number) of bleached linen yarns, the loss in bleaching is fixed at 20 per cent, for full, 18 per cent, for three-quarters, and 15 per cent, for one-half bleach. | According to Spon, samples of flax fibre exposed for two hours to steam at 2 atmospheres, boiled in water for three hours, and again steamed for four hours, lost only 3.5 per cent, in weight, while Manila hemp under these conditions lost 6.07, hemp 6.18 to 8.44, and jute 21.39 per cent. 280 THE TEXTILE FIBRES. As flax is a better conductor of heat than cotton, linen fabrics always feel colder to the touch than those made from cotton. The bast-cells of the flax fibre may be isolated by treatment with a dilute chromic acid solution. They are cylindrical in form and taper to a point at each end. At the middle they measure 12 to 26 //, with an average of about 15 p.* The length varies from 4 to 66 mm., with an average of about FIG. 72. Flax Fibre. (Xsoo.) A , longitudinal view, showing jointed structure and tracing of lumen; B, cross-sections. 25 mm. The ratio of the length of the cell to its breadth is about 1,200. Under the microscope the surface of the cell appears smooth or marked longitudinally, with frequent transverse fissure lines and jointed structures. On treatment with chlor-iodide of zinc the latter are colored much darker than the rest of the cell and are thus rendered more apparent. The lumen appears in the centre of the cell as a narrow yellow line, and it is usually completely filled with protoplasm. With iodin and sulphuric acid linen gives a blue color, which, however, develops less quickly than with cotton; with tincture of madder an orange color is produced, while fuchsin (followed with ammonia) gives a permanent rose color in contradistinction to cotton. These * According to Vetillard, 15 to 37 //, with an average of 22 fi. LINEN. 281 tests, however, are only applicable to unbleached linen, for the cellulose of bleached linen shows little or no chemical difference from that of cotton. In cross-section the cells of flax are polyg- onal, with rounded edges, show a small lumen, and a relatively thick cell- wall (see Fig. 72). In these respects they are very similar to hemp, but may be distinguished from the latter, how- ever, in that they do not aggregate in thick bundles, but are more or less isolated from each other, so that the cross-section frequently shows but one cell, and seldom more than three or four (see Fig. 72).* The following analyses show the composition of two typical specimens of flax (H. Miiller) : i. u. Per Cent. Per Cent. Water (hygroscopic) 8. 65 10. 70 Aqueous extract 3 . 65 6 . 02 Fat and wax 2 . 39 2 . 37 Cellulose 82.57 71-50 Ash (mineral matter) f o . 70 1.32 Intercellular matter 2 . 74 9 . 41 Highly purified flax appears to approximate very closely to both the composition and chemical properties of cotton. The ordinary flax fibre of trade may be said to contain about 5 per cent, less of cellulose than cotton, there being about that much more impurity present in the form of intercellular matter and pectin bodies.t Linen, however, appears to be free from woody * Other differences from hemp exhibited by the linen fibre are: (a) the cross- section does not show an external yellow layer of lignin when treated with iodin and sulphuric acid; (&) it gives reactions for pure cellulose only, that is, iodin and sulphuric acid color the fibre a pure blue, and anilin sulphate gives no color, though at times there are shreds of parenchymous tissue present which are colored yellow by this latter reagent and appear to be lignified; (c) the lumen of the hemp fibre is seldom filled with yellowish protoplasm like that of the linen fibre; (d) the linen fibres end in sharp points, whereas those of hemp do not. f According to Wiesner, the ash of the linen fibre amounts to from 1.18 to 5.93 per cent., and shows no evidence of crystals. | The flax fibre contains a certain wax-like substance, varying in amount from 0.5 to 2 per cent. It may be extracted from the fibre by means of benzene or ether. The color of the wax obtained varies with that of the flax from which it is obtained. It has a rather unpleasant odor, resembling flax itself. Its melt- ing-point is 61.5 C., and its specific gravity at 60 F. is 0.9083. According to Hofmeister, this wax consists of 81.32 per cent, of unsaponifiable waxy matter 282 THE TEXTILE FIBRES. or lignified tissue, as it gives none of the reactions for these. The linen fibre swells up greatly when treated with an ammoniacal solution of copper oxide, but, unlike cotton, it does not exhibit the peculiar sausage-shaped appearance, nor does it dissolve com- pletely. The hygroscopic moisture in linen is about the same as in cotton; in fact, all vegetable fibres appear to contain approxi- mately the same amount (from 6 to 8 per cent.).* FIG. 73. Flax Fibre. (Xsoo.) Stained with methyl violet. J, joint-like forma- tions; F, fissure- like markings. (Micrograph by author.) Due to differences in structure, linen is more easily disinte- grated than cotton, and consequently does not withstand the and 18.68 per cent, of saponifiable oil. Of the latter, 54.49 per cent, is free fatty acid. The waxy matter has a melting-point of 68 C., and apparently is a mixture of several bodies. The principal one resembles ceresin, and there are also present ceryl alcohol and phylosterin. The saponifiable matter appears to contain small quantities of soluble fatty acids, like caproic, stearic, palmitic, oleic, linolic, lino- lenic, and isolinolenic. * The amount of " regain " allowed in the conditioning of linen at Roubaix is from 10 to 12 per cent. Wiesner gives the amount of hygroscopic moisture in linen as 5.7 to 7.22 per cent. The Turin Congress fixed the regain for linen at 12 per cent. LINEN. 283 action of boiling alkaline Delations, solutions of bleaching pow- der, or other oxidizing agents, etc., as well as cotton. Towards mordants and dyestuffs, etc., linen does not react as readily as cotton, hence its manipulation in dyeing is more diffi- cult. In general, however, it may be said that the dyeing and treatment of linen are practically the same as with cotton. The oil- wax group of constituents in the flax fibre plays an important part in the spinning * of this fibre, and the failure of many of the artificial processes of retting flax may be attributed to the fact that the fibre is left with a deficiency of these constitu- ents. In the breaking down of the cuticular celluloses, whether in the retting or in the bleaching processes, these waxes and oils are separated. Their complete elimination from the cloth neces- sitates a very elaborate treatment, such as is represented by the " Belfast Linen Bleach." * Linen yarns are known as hand-spun or machine-spun; the former are softer and smoother and more elastic, but uneven and less rounded in form, while ma- chine-spun yarns are stiff and rough, but of uniform thickness and perfectly round. According to the method of spinning, linen yarns are also known as dry-spun or wet-spun; the former have greater firmness, but higher numbers can be obtained by wet-spinning. Tow yarns are prepared from waste, and are characterized by numerous knots due to particles of shives. In the English system, the counts of linen yarns are expressed by the number of leas in a pound, each lea measuring 300 yards. To obtain the count of cotton yarn corresponding to the count of linen yarn, the latter number is divided by 2.8. In the French system, the count of linen yarns is the number of hanks of 1000 metres contained in 500 grams. In the Austrian system, the count indicates the number of hanks to 10 English pounds, each hank containing 3600 ells (i ell= 30.68 inches). CHAPTER XVI. JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. i. Jute is a fibre obtained from the bast of various species of Corchorus, growing principally in India and the East Indian Islands.* The most important variety is Corchorus capsularis or Jew's mallow, which is grown throughout tropical Asia not only as a fibre plant, but also as a vegetable. Other varieties are C. olitorius, C. fuscus, and C. decemangulatus; the latter two, however, yield but a small proportion of the jute fibre to be found in trade. f The jute plant grows to a height of from 10 to 12 feet and its fibrous layer is very thick, so that it yields from two to five times as much fibre as flax. The Corchorus capsularis is an annual plant, growing from 5 to 10 feet in height, with a cylindrical stalk as thick as a man's finger, and seldom branching near the top. The leaves, which are of light green color, are from 4 to 5 inches long by 1 1 inches broad * Jute was first introduced into Europe about the year 1795. It has been used for spinning since 1830. f The commercial fibre known as Chinese jute is not a variety of jute at all, but is derived from Abutilon avicenna or Indian mallow. The latter grows ex- tensively as a weed in America. The bast fibre is white and glossy, and has considerable tensile strength. It is also used for the making of paper stock. Chemically it appears to consist of bastose, and hence resembles jute in its be- havior towards dyestuffs. The plant produces about 20 per cent, of fibre, but is of doubtful economic value. Another somewhat similar variety is the Abutilon incanum, which grows in Mexico; it is said that the Indians used the fibre from this plant for making hammocks, ropes, and nets, which are so durable that they last from seven to ten years in constant use. There are also several East Indian species of Abutilon, among which may be named A. indicum, A. graveolens, A. muticum, and A. polyandrum, all of which are fibre plants suitable chiefly for cordage; the latter yields a long silky fibre resembling hemp. The A. periploci- jolium, growing in tropical America, yields a very good bast fibre, quite long, and of a creamy yellow color. 284 JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 285 towards the base, but tapering upward into a long sharp point with edges cut into saw-like teeth, the two teeth next the stalk being prolonged into thistle-like points. The flowers are small and of a yellowish white color, coming out in clusters of two or three together opposite the leaves. The seed-pods are short and globular, rough and wrinkled (see Fig. 74, A). The C. olitonus is precisely like the former in general appearance, shape of leaves, A B FIG. 74. A, seed-vessels of Corchorus capsularis; B, seed-vessels of Corchorus olitorius. (After Bulletin U. S. Dept. Agric.) color of flower, and habits of growth; but it differs entirely in the formation of the seed-pod, which is elongated, almost cylin- drical, and of the thickness of a quill (see Fig. 74, B). The preparation of the fibre from the jute plant is a rather simple operation. The stalks are freed from leaves, seed-cap- sules, etc., and retted by steeping in a sluggish stream of water. After a few days the bast becomes disintegrated, and the retted stalks are pressed and scutched. The fibre so obtained is re- markably pure and free from adhering woody fibre and other 286 THE TEXTILE FIBRES. tissue. The prepared fibre usually has a length of from 4 to 7 feet, possesses a pale yellowish brown color, though the best qualities are pale yellowish white or silver gray, and exhibits considerable lustre and tensile strength. The ends of the plant, together with the various short waste fibres, appear in trade under the name of " jute butts " or " jute cuttings," and are employed as a raw ma- terial for paper-manufacturing. Kerr (Report on Jute in Bengal, 1874) enumerates the follow- ing varieties of jute as being the most common in trade: (a) Uttariya, or northern jute, by far the best variety, as it possesses the best qualities as regards length, color, and strength; it is never equal to the Desi and Deswal varieties, however, in soft- ness, (b) Deswal, which is next in commercial value, is chiefly desirable on account of its softness, fineness, bright color, and strength, (c) Desi jute has a long, fine, soft fibre, but it has the defects of being fussy and of a bad color, (d) Deora jute is strong, coarse, black, and rooty, and is much overspread with runners; it is used for the manufacture of rope, (e) Narain- ganji jute is very good for spinning, being soft, strong, and long; but the fibre as it appears in trade has a foxy brown color which detracts from its value, though this defect is apparently due to imperfect steeping. (j)Bakrabadi excels particularly in color and softness, (g) Bhatial jute is very coarse, but strong, and is in demand for the manufacture of rope, (ti) Karimganji is a fine variety, long, very strong, and of good color, (i) Mirganji is of medium quality, (j) Jangipuri jute is of short fibre, weak, and of a foxy brown color, and not suitable for spinning. According to Hohnel, the bast-cells of the jute fibre are from 1.5 to 5 mm. in length, and from 20 to 25 /* in thickness, the mean ratio of the length to the breadth being about 90; consequently, the elements of the jute fibre are relatively short. In cross- section the jute fibre shows a bundle of several elements bound together ; these are more or less polygonal in outline, with sharply defined angles. Between the separate elements is a narrow median layer (see Figs. 75 and 77), which, however, does not give a much darker color with iodin and sulphuric acid than the cell- wall itself. The lumen is about as wide, or at times even wider, JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 287 than the cell- wall, and in cross-section is round or oval. Longi- tudinally the lumen shows remarkable constrictions or irregular thicknesses in the cell- wall (see Fig. 78), though towards the end of the fibre the lumen broadens out considerably, causing the cell-wall to become very thin. Externally the fibre is smooth and lustrous, and has no jointed ridges or transverse markings such as seen in linen or most other bast fibres. In its chemical composition jute is apparently quite different from linen and cotton, being composed of a modified form of FIG. 75. Jute Fibre. a, cross-sections; b, longitudinal views; c. ends. (After Cross and Bevan.) cellulose known as lignocellulose or bastose. Bastose, properly speaking, is a compound of cellulose with lignin.* It behaves quite differently from cellulose towards various reagents, its chief distinction being that it is colored yellow by iodin and sulphuric * Mtiller gives the following method for thi isolation of pure cellulose from jute : Two grams of the material are dried at from 110 to 115 C. In order to remove wax, etc., it is next treated with a mixture of alcohol and benzol, and is subse- quently boiled with very dilute ammonia water. The softened mdS is then pulverized in a mortar, and placed in a large, glass-stoppered flask with 100 cc. of water. From 5 to 10 cc. of a solution of 2 cc. of bromin in. 500 cc. of water are added, until a permanent yellow is obtained after standing twelve to twenty-four hours. The substance is then filtered, washed with water, and heated to boiling with water containing a little ammonia. After this it is filtered, washed, and again treated with the bromin solution, as above indicated, until a permanent yellow color is obtained. The fibre is then boiled with dilute ammonia, and on filtering and washing leaves a residue of pure white cellulose. 2 88 THE TEXTILE FIBRES. acid, whereas pure cellulose is colored blue. With dilute chromic acid, to which a little hydrochloric acid has been added, jute gives a blue color. When treated with an ammoniacal solution of copper oxide the fibres swell considerably, but do not readily dissolve. With chlor-iodide of zinc jute gives a yellow color. The following table gives the principal reactions used to dis- tinguish cellulose from bastose : * Reagent. Cellulose. Bastose. lodin and sulphuric acid. . Anilin sulphate and sul- phuric acid Blue color No change Yellow to brown color Deep-yellow color Basic dyestuffs No change Becomes colored Weak oxidizing agents. . . . Schweitzer's reagent No change Quickly dissolves Quickly decomposes Swells, becomes blue, and slowly dissolves Analysis of jute shows it to consist of the following : Constituents. Nearly Color- less Specimen. Fawn-colored Fibre. Brown Cuttings , Ash . 0.68 \Vater (hygroscopic)"}" -03 64 12. c8 Aoueous extract 1 .03 1.63 7 .Q4 Fat and wax O. 3Q o. 32 O.4X Cellulose 64. 24. 63 o? 6l 74. Incrusting and pectin matters 24. 4.1 2s 36 2 1 2O The ash of jute consists principally of silica, lime, and phos- phoric acid; manganese is nearly always present in small amount. Bastose is dissolved by the usual cellulose solvents, such as zinc chloride and Schweitzer's reagent; and from these solutions the lignocellulose may be precipitated by dilution or acidifying respectively, though the precipitation is never complete, there * According to Cross and Bevan, the jute fibre may be regarded as an anhydro- aggregate of three separate compounds: (a) A dextrocellulose allied to cotton, (6) a pentacellulose yielding furfural and acetic acid on hydrolysis; (c) lignone, a quinone which is converted by chlorination and reduction into derivatives of the trihydric phenols. f According to Wiesner, fresh jute contains about 6 per cent, of hygroscopic moisture and brown jute about 7 per cent. When completely saturated with moisture the former will contain about 23 per cent, and the latter 24 per cent. The Turin Congress adopted a regain of 13! per cent, for the conditioning of jute. JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 289 remaining in solution from 10 to 25 per cent, of the original substance. The chief chemical difference between jute and the pure cel- lulose fibres is in the ability of the former to combine directly with basic dyestuff s. In fact it acts in this respect similar to cotton which has been mordanted with tannic acid. Jute is also more sensitive to the action of chemicals in general than cotton or linen. On this ac- count it cannot be bleached with much success, as treatment with alkalies and bleaching powder weakens and disinte- grates the fibre to a considerable extent.* The jute fibre is relatively weak when compared with other bast fibres, and the chief reasons for its prominence among the textile fibres are its fineness, silk-like lustre, and adaptability for spinning. The plant is also easy to cultivate, and returns a large yield of fibre. The chief defect of jute is its lack of durability; when exposed to dampness it rapidly deteriorates; and even under ordinary conditions of wear, the fibre gradually becomes brittle and loses much of its strength. The bleached fibre is especially liable to such deterioration; it gradually loses its whiteness, and, evidently due to oxidation, becomes dingy and yellowish brown in color. Jute is principally used for the making of coarse woven fabrics, such as gunny sacks and bagging, where cheapness is of more consequence than durability.! It also finds considerable use in the tapestry trade, being used as a binding-thread in the weaving FIG. 76. Jute Fibre. (X3QO.) (Micrograph by author.) * Samples of jute fibre exposed for two hours to steam at 2 atmospheres, fol- lowed by boiling in water for three hours, and again steamed for four hours, lost 21.39 P er cen *- by weight, being about three times as great a loss as that suffered by hemp, Manila hemp, phormium, and coir. A similar test for jute with flax, hemp, ramie, and other fibres showed as great a loss, while flax lost less than 4 per cent, and ramie a small fraction under i per cent. t Jute is the cheapest fibre used in American textile manufacturing, and it is employed in greater quantities than any other except cotton and sisal. 290 THE TEXTILE FIBRES. of carpets and rugs. On account of its high lustre and fineness, it is also adapted for the preparation of cheap pile fabrics for use in upholstery. Of late years a variety of novelty fabrics for dress- goods have also been made from jute, used in conjunction with woolen yarns. Jute has also been used extensively as a substitute FIG. 77. Cross-section of Jute-straw. Showing transverse section of portion of bast only, giving the anatomy of the fibrous tissue, the form of the bast- cells, and the thickening of the cell-walls. (Cross and Bevan.) for hemp, for which purpose the former is rendered very soft and pliable by treatment with water and oil. A mixture of 20 parts of water with 2.5 parts of train-oil is sprinkled over 100 parts of jute fibre. It is left for one to two days, then squeezed and heckled, whereby the fibres become very soft and isolated. Jute is also largely used in the manufacture of twine and smaller sizes of rope. Owing to its cheapness, it is used to adulterate other more JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 291 valuable fibres, but due to its tendency to rapid deterioration, its use in this connection should not be encouraged. The " jute butts " and miscellaneous waste are extensively employed as a raw material in the manufacture of paper. FIG. 78. Jute Fibre. (X3oo.) L, lumen; C, constrictions in lumen; E, end of fibre. (Micrograph by author.) 2. Ramie, or China Grass, is a fibre obtained from the bast of the stingless nettle, or Bcehmeria. Alt:.ougli frequently con- founded in trade, ramie and China grass are hi reality two dis- tinct fibres. The former (also known as rhea) is obtained from the Bcehmeria tenacissima, which grows best in tropical and sub- tropical countries. The latter is obtained from Bcehmeria nivea, which grows principally in the more temperate climes.* Tre * The ramie plant is of more robust habit and has larger leaves, which are green on both sides; hence the name green ramie, which its fibre sometimes receives in trade. The China grass plant has leaves which are white felted beneath ; hence the name white ramie sometimes given to its fibre. 292 THE TEXTILE FIBRES. two species, however, are so similar in nature, and the fibres are so universally confounded with one another, that it is only possi- ble to consider them as a single substance, which will be done under the name of ramie. The plant is a shrub, reaching 4 to 6 feet in height, and is very hardy. It is cultivated largely in China and India, and has also been grown successfully in Amer- ica.* The fibre of ramie is very strong and durable, probably rank- ing first of all vegetable fibres in this respect. f It is also the least FIG. 79. Ramie Fibre. (X3oo.) a, sections; b, longitudinal view; c, ends. (After Cross and Bevan.) affected by moisture. It has three times the strength of hemp, and the fibres can be separated to almost the fineness of silk. The fibre is exceptionally white in color, being almost compa- rable to bleached cotton in this respect, and does not appear to * The use of China grass or ramie was probably known to the Chinese at a very early period; some writers have also attempted to show that it was used in Egypt several thousand years ago contemporaneously with flax for the prepara- tion of mummy-cloths. f From experiments made on the tensile strength of isolated filaments of ramie, it appears that this fib:e has a breaking strain of from 17 to 18 grams. Ramie degummed in the laboratory of Fremy showed a breaking strain of from 21 to 22 grams, and by very careful degumming it has been possible to attain a strength of from 35 to 40 grams. Isolated fibres of hemp show a breaking strain of only 5 grams. JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 293. have any natural coloring-matter at all. It also has a high lustre, excelling linen in this respect.* The following table gives the chief physical factors of the ramie fibre in comparison with the other principal fibres: Ramie. Hemp. Flax. Silk. Cotton. Tension IOO ^6 2 ^ 1 3 12 Elasticity IOO 7 ir 66 400 IOO Torsion IOO QC 80 600 4.OO Having such excellent qualities as a fibre, it would be natural tl'.at ramie should have had considerable attention bestowed upon FIG. 80. Ramie Fibre. (X34O.) z>, swollen displacements; r, fissures; e, point or end; q, cross-sections; *, inner layers of fibre-wall; /, lumen; sch, strati- fications. (Hohnel.) it. The chief difficulty in the way of its universal and wide-spread adoption has been the lack of an efficient process for properly * Cottonized ramie is fibre on which the degumming process has been carried too far, with the result that the individual filaments have been more or less sepa- rated into their elements; the fibre is white, but without the characteristic trans- parency and lustre of ordinary ramie. 294 THE TEXTILE FIBRES. decorticating the fibre from the rest of the plant. In China and India, where this fibre has long been employed for the weaving of the finest and most beautiful fabrics,* the decortication of the fibre is carried out by hand. This, of course, would be imprac- ticable in western countries. FIG. 81. Ramie Fibre. (X35.) (Micrograph by author.) The fibre is easily separated from the leaf, and does not require a retting process.* In their microscopical appearance the fibre brushes. The parenchym or pith of the leaf squeezed out in the extraction of the fibre is used as a substitute for soap, as it possesses remarkable detergent properties. In Mexico the fibre is commonly known as "istle." * Sisal hemp is cleaned from the leaves by machines which scrape out the pulp and at the same time wash the fibre in running water. It is then hung in the sun to dry and bleach for from one to three days, after which it is baled for mar- ket. More than 600,000 bales, averaging about 360 Ibs. each, were imported by the United States during 1903; the price during the past decade has varied from 2f to 10 cents per pound. Sisal fibre of good quality is of a slightly yellowish color, z\ to 4 feet in length, somewhat harsher and less flexible than Manila hemp, but next to that the strongest and most extensively used hard fibre. It is used in the manufacture of binder twine, lariats, and general cordage, aside from marine cordage and derrick-ropes. It cannot withstand the destructive action of salt water, and its lack of flexibility prevents it from being used to advantage for running over pulleys or in power transmission. It is extensively used in mix- tures with Manila hemp. (Yearbook, Dept. Agric., 1903.) 318 THE TEXTILE FIBRES. bundles often show an interlaced formation with a peculiar spiral thickening. The fibre elements are from 1.5 to 4 mm. in length and from 20 to 32 /* in breadth, the ratio of the length to the diam- eter being about 100. They are usually quite stiff in texture, and show a remarkable broadening towards the middle. The width of the lumen is frequently greater than that of the cell-wall. The ends are broad, blunt, and thick, but seldom forked. The cross- sections are colored yellow by iodin and sulphuric acid, and show no evidence of a median layer between the elements. The sections are polygonal in outline, but often have rounded edges, and the bundles are usually close together. The lumen in the cross- section is large and polygonal in shape, though the edges of the lumen are more rounded than those of the walls. The ash obtained from the ignition of the fibre shows the presence of glistening crystals of calcium carbonate, which are derived from the original crystals of calcium oxalate to be found clinging to the fibre bundles. They are usually in longitudinal series, about 0.5 mm. long, and taper off at the ends to a chisel shape, resembling a thick needle in form, but having a quadrilateral cross-section. 9. Aloe Fibre, or Mauritius Hemp, is obtained from the leaf of various species of aloe plants growing in tropical climates.* The principal plant employed for Mauritius fibre is Furcraa j&tida. In Porto Rico it is known as maguey, but is not to be identified with the Mexican fibre of the same name; in Hawaii it is called malino, which is probably a corruption of manila. The only locality in which the fibre is produced commercially is the island of Mauritius. This fibre is often confounded with that of the Agave americana, but it is of different origin. Aloe fibre, however, is very similar to Sansevieria fibre, and is hardly Jio be distinguished from it in either physical or microscopic appear- /ance.f The fibre elements are from 1.3 to 3.7 mm. in length and * The commercial supply of aloe fibre is obtained from Africa. f The fibre is whiter and softer than other hard fibres, but it is weaker than sisal. It is used in the manufacture of gunny bags, halters, and hammocks, but more largely for mixing with Manila and sisal in making medium grades of cord- age. When the better grades of cordage fibre (Manila and sisal) are abundant and quoted low in the market, Mauritius is likely to fall below the cost of produc- tion. (Yearbook, Dept. Agric., 1903.) JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 319 from 15 to 24 / in breadth. Although uniformly broad, the cell- wall is thin. The fibres are usually cylindrical and not flattened; FIG. 98. True and False Sisal. A, leaves of true sisal hemp plant; B, leaves of false plant showing thorny edges. (After Bulletin U. S. Dept. Agric.) they show occasional fissure-like pores (see Fig. 102). The cross-sections are polygonal, with slightly rounded edges. The lumen is usually somewhat broader than the walls, and in the 320 THE TEXTILE FIBRES. cross-section is polygonal with rounded sides. In the Sanse- vieria fibre the lumen in the cross-section is usually larger, and the cell- walls consequently thinner; furthermore the lumen has a sharp-edged polygonal form (see Fig. 109)-. FIG. 99. Floridal Sisal Hemp. Agave decipiens. (After Dodge.) 10. Pita Fibre is obtained from the leaf of the Agave amer- icana * or century plant ; it is also known as aloe fibre. There * The Agave is a genus of fleshy-leaved plants belonging to the Amaryllidacea, chiefly found in Mexico and Central and South America. They are called "cen- tury" plants because they flower but once. From some of the Mexican specie, there is obtained a distilled liquor known as mescal, also the fermented beverage called pulque. The fibre from A. americana (maguey plant) is a structural fibr- composed of large filaments readily separated by friction. According to Spon the agave requires about three years to come to perfection, but it is exceedingle hardy, easy of cultivation, and very prolific, and grows in arid wastes where scarcely any other plant can live. It perishes after inflorescence, then sends up numerous shoots. In Mexico 5000 to 6000 plants may be found on an acre; the average number of leaves is 40, each measuring 8 to 10 feet long and i foot wide, and yielding 6 to 10 per cent, by weight of fibre. JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 321 FIG. loo. Sisal Hemp. (X3.) W, cell-wall; P, end of fibre; 5, spiral- shaped sclerenchymous tissue. (Micrograph by author.) FIG. 101. Mauritius Hemp. (Xsoo.) (Micrograph by author.) 322 THE TEXTILE FIBRES. are several varieties of this fibre, which are known by their Mexican or Indian names. The best known of these are the henequen (Agave saxi), the ixtle (Agave americana), and the lechuguilla (Agave heteracantha). The latter is also known as Tampico hemp. The henequen is principally grown in Yucatan, and was extensively used and highly prized by the ancient Mex- FlG. 102. Fibre from Aloe speciosus. (X325.) e, ends; /, longitudinal view; g, cross-section; r, fissure-like pores in cell- walls. (Hohnel.) cans, and still is at the present time. In recent years it has been quoted in European markets at $7.30 per 100 Ibs. The fibre is white to pale straw in color, is stiff and short, has a rather thin wall, and furthermore is liable to rot. The fibres have a distinctive wavy appearance, and another peculiarity is its great elasticity. According to Royle, Indian pita has been found superior in strength to either coir, jute, or sunn hemp, the breaking strain on similar ropes made of these materials being as follows: Pounds. Pita 2519 Coir 2175 Jute 2456 Sunn hemp 2269 JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 3 2 3 Russian hemp and pita, on comparison, gave a relative strength of 1 6 to 27. Besides its use as a cordage fibre, pita is also em- ployed for the making of a very delicate and beautiful lace known as Fayal. In its microscopical characteristics pita is very sim- ilar to sisal hemp. ii. Pineapple Fibre, or Silk Grass,* is obtained from Ananas saliva or pineapple plant. This fibre has great durability and is unaffected by water. It is very fine in staple and highly lustrous, FiG. 103. Pita Fibre. (X300.) Agave americana. (Micrograph by author.) and is white, soft, and flexible. It is used in the manufacture of the celebrated pi~a cloth in the Philippine Islands. According to Taylor, a specimen of tjiis fibre was subdivided to one ten- thousandth of an inch in thickness, and was considered to be the most delicate in structure of any known vegetable fibre. Micro- scopically it is distinguished from all other leaf fibres by the extreme fineness of its fibre elements. These are from 3 to 9 * This term "silk grass," though applied to this fibre, is both meaningless and a misnomer. 3 2 4 THE TEXTILE FIBRES. mm. in length and from 4 to 8 /z in thickness. The lumen is very narrow and appears like a line. The cross-sections are polygonal in outline and frequently flattened. The sections form in com- pact groups which are often crescent-shaped, and are enclosed in a thick median layer of lignified tissue. FIG. 104. Pineapple Plant. (After Dodge.) * 12. Coir Fibre is obtained from the fibrous shell of the cocoa- nut. For the preparation of the fibre, the unripe nuts are steeped in sea-water for several months, after which the fruit is beaten and washed away with water. The residual reddish brown fibrous mass is decorticated by tearing and hackling into fibres about 10 inches in length. The fibre occurs in the form of large, stiff, and very elastic filaments, each individual of which is round, smooth, and somewhat resembling horse-hair. It is principally used for making mats and cordage. It possesses remarkable te- nacity and curls easily. In color it is cinnamon brown. It possesses marked microscopical characteristics ; the fibre elements are short JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 325 and stiff, being from 0.4 to i mm. in length and from 12 to 24/1 in diameter, the ratio of the length to the thickness is only 35. The cell-wall is thick, but rather irregularly so, in consequence of which the lumen has an irregular outline, resembling indentations (see Fig. 107). The points terminate abruptly and are not sharp, FIG. 105. Section of Cocoanut. (1/5.) a, husk containing fibre; b, the fruit or edible portion. (After Bulletin U. S. Dept. Agric.) and there appear to be a large number of pore-canals penetrating, the cell- wall. On the surface the fibre bundles are occasionally covered with small lens-shaped, silicified stegmata, about 15 /* in breadth. These stegmata fuse together on ignition, giving a blis- ter on the ash. If the fibre is boiled with nitric acid previous to its ignition, the stegmata then appear in the ash like yeast-cells hanging together in the form of round, silicious skeletons.* The cross-section of the fibre is oval in shape and yellowish brown in color, and enclosed in a network of median layers. Coir fibre is employed in the South Seas instead of oakum for caulking vessels, and it is claimed that it will never rot. The principal use for coir, however, is for cordage and matting. For cable-making it * Coir gives the following microchemical reactions: with iodin and sulphuric acid, golden yellow; with anilin sulphate, intense yellow; Schweitzer's reagent does not attack the fibre. According to Schlesinger, coir contains 20.6 per cent, of hygroscopic moisture. 326 THE TEXTILE FIBRES. is said to be superior to all other fibres, on account of its lightness and great elasticity. It also has a great resistance to mechanical wear. Wright gives the following tests on various cordage fibres: Pounds. Hemp 190 Coir 224 Bowstring hemp 316 13. Istle Fibre, otherwise known as Tampico fibre, is ob- tained from the leaves of several species of Mexican plants which FIG. 106. Coir Fibre. (X3oo.) s, serrations in wall of lumen; p, pores in wall; Si, silicious skeleton from stigmata. (Micrograph by author.) are principally found in the desert table-lands of northern Mexico. The most important istle fibres are Jaumave lechuguilla, Jaumave istle, lechuguilla, Tula istle, Palma samandoca, and Palma pita* 14. Nettle Fibre.f This fibre is used to some extent for spin- ning, being cultivated for this purpose in certain parts of Germany The principal plants yielding the fibre are Agave lophantha, A. lechuguilla, and Samuella earner osana. * Palma istle fibre is 15 to 35 inches in length, usually coarser and stiff er than sisal, yellow in color, and somewhat gummy. Tula istle is 12 to 30 inches long and nearly white in color. Jaumave istle is 20 to 40 inches long, rarely longer, almost white, and nearly as strong and flexible as sisal. The importations of istle fibre into the United States have increased from less than 4000 tons in 1900 to more than 12,000 tons in 1903. Istle fibre has long been used as a substitute for bristles in the manufacture of brushes, and it is now being employed in increasing quantities in the cheaper grades of twine, such as lath twine, baling rope, and medium grades of cordage. Introduced at first as an adulterant or substitute for better fibres, it seems destined to find, through improved processes of manufac- ture, a legitimate place in the cordage industry. If machines are devised for cleaning this fibre in a satisfactory manner, it is thought that the thousands of acres of lechuguilla plants in western Texas may be profitably utilized. f See Wiesner, Rohstoffe des Pftanzenreiches, vol. 2, p. 214; Moller, Die Nessel- faser, Polytechnische Zeitung, 1883; Hohnel, Mikroskopie der Faserstoffe, p. 52; Dodge, Useful Fibre Plants, p. 323. JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 327 and in the province of Picardy in France. The product known by the specific name of nettle fibre is obtained from two species FIG. 107. Coir Fibre. (Xsoo.) (Micrograph by author.) of the stinging nettle,* Urtica dioica and Urtica urena. The Bcehmeria (see Ramie and China grass) are also nettle plants, but belong to the stingless variety. The Urtica dioica yields the FIG. 108. A Leaf of Agave heteracantha. (After Bulletin U. S. Dept. Agric.) largest amount of fibre, but of large diameter and very thin cell- wall ; the fibres from the second species, Urtica urena, are much * The stinging nettle is also common in the United States; it grows princi- pally on waste lands. It has not been used as a fibre plant in this country how- ever. In Sweden it is cultivated to some extent for its fibre, being known as Swedish hemp; it is used for cordage, cloth, and fish-lines. In India it is known as Bichu or Chicru, meaning scorpion or stinger. 3 28 THE TEXTILE FIBRES. smaller in diameter and have a thick cell-wall, resembling linen fibres to a great extent; its chief drawback is the small yield of fibre from the plant. The nettle fibre appears to consist of ' pure cellulose, with occasional traces of lignin on the surface. It gives the following microchemical reactions: (a) with iodin-sulphuric acid reagent, blue coloration ; * (b) with ammoniacal fuchsin solution, no coloration; (c) with sulphate of anilin, no coloration; (d) with chlor-iodide of zinc, bluish violet coloration; (e) with chlor- iodide of calcium, rose-red coloration. The fibres of Urtica dioica vary in length from 5 to 55 mm. (Vetillart) and in diameter from 0.020 to 0.080 mm. Under the microscope the fibres are characterized externally by fine oblique striations ; the ends of the fibres are finely pointed. f On account of the thin cell- wall, the nettle fibre gives only faint colorations when viewed under polarized light. In Germany the nettle fibre is spun into a greenish colored yarn known as Nesselgarn, this is woven into a cloth called Nesseltuch, which may be bleached to a pure white, and much resembles linen cloth. 15. Fibre of Urena Sinuata. The plant from which this fibre is obtained is a small shrub growing in Asia and South America. In America it is known as Caesar weed; in Vene- zuela it goes by the name of Cadilla. The bast fibre resembles jute in appearance, it being yellowish in color, of considerable brilliancy, and also like jute it deteriorates in moist air. The average length of fibre bundles is 6 feet. The fibre-cells, accord- ing to Wiesner, have a length of about 1.8 mm., and an average diameter of 15 /. The lumen of the fibre is very irregular in width, but is mostly rather broad, though not so large as that of jute. With iodin and sulphuric acid the fibre gives a yellow * The lumen of the fibre, especially towards the ends, is often filled with mat- ter which gives a yellow color with this reagent. f The cross-sections of the fibres are oval and show thin cell-walls, which, however, at times may become quite thick, owing to irregularities in the struc- ture of the fibre. The fibre is souple, long, and soft to the touch; like ramie it possesses great resistance to water; it is, however, comparatively weak in strength, owing to the thin cell-wall and irregular structure. JUTE, RAMIE, HEMP, AND MINOR VEGETABLE FIBRES. 329 color; anilin sulphate also gives a deep yellow, which indicates strong Irmifi cation ; Schweitzer's reagent produces a strong swelling of the cell- wall. There may/ often be observed on Urena fibres, under the microscope, cells of parenchymous tissue contain- ing crystalline deposits. The ash of the fibre also shows aggre- FIG. 109. Fibre from Sansevieria. (X325-) e, ends; /, longitudinal view; Upholstery and matting fibres. Saw palmetto, Serenoa serrulata Cocoanut fibre, Cocos nucifera Esparto grass, Stipa tenacissima, a paper fibre. Vegetable sponge, Lufta cegyptica, a substitute for sponge. The native vegetable fibres of the United States that are produced in com- 334 QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 335 also be included analogous animal hairs, such as mohair, cash- mere, etc. Other animal fibres, such as cow-hair and horse-hair, may easily be distinguished even by the naked eye. Of course there are numerous other fibres of vegetable origin which are employed more or less for textile materials, but either they are not liable to occur in conjunction with wool, or they may be readily distinguished from the latter without requiring a special examination. The best method of distinguishing qualitatively between the various fibres above mentioned is by the use of the microscope, whereby their characteristic physical appearance may be readily observed. Each of the fibres in question presents certain micro- scopical peculiarities, so that no difficulty is encountered in dis- tinguishing between them. The difference in the microscopical appearance of these fibres may be comparatively observed by reference to the figures given in the preceding pages. 2. Qualitative Tests. A rough physical test to distinguish between animal and vegetable fibres is to burn them in a flame. Vegetable fibres burn very readily and without producing any disagreeable odor; animal fibres, on the other hand, burn with some difficulty and emit a disagreeable empyreumatic odor re- sembling that of burning feathers. The burnt end of the fibre is also characteristic, vegetable fibres burning off sharply at the end, whereas animal fibres fuse to a rounded, bead-like end. Tables I and II exhibit the characteristic chemical reac- tions of the principal fibres, and by suitably employing these tests the various fibres may be easily distinguished from one another. The reagents employed for the tests in the tables may be prepared as follows: (1) Madder Tincture. Extract i gm. of ground madder with 50 cc. of alcohol, and filter from undissolved matter. (2) Cochineal Tincture. This is made in the same manner as the above, using i gm. of ground cochineal insects. mercial quantities are cotton, hemp, flax, palmetto fibre, and vegetable hair from Spanish moss. For the year ending June 30, 1896, the value of raw vege- table fibres imported into the United States was about $20,000,000. 336 THE TEXTILE FIBRES. TABLE I. Test. Wool. Silk. Linen. Cotton. DYESTUFF TESTS. Ivladder tincture Nil Scarlet Red Dyed Nil Partly diss. Nil Violet to brown Red to brown Black Black ppt. Swells only Undissolved Nil Scarlet Red Dyed Nil Dissolves Nil Nil Nil Nil No ppt. Nil Dissolves Orange Violet Nil Nil Dyed Yellow Light red Nil Nil Dyed Cochineal tincture Fuchsin Acid dyes in general Ivlikado yellow ACTION OF VARIOUS SALTS. Zinc chloride Fibre undiss., yellow color Black color Nil. Nil Nil Nil Swells and partly dissolves Undissolved Stannic chloride . ... Silver nitrate Mercury nitrate (Millon's) Cupric or ferric sulphate. . ^odiurn plurnbite Ammoniacal copper oxide. Ammoniacal nickel oxide. (3) Fuchsin Solution. Dissolve i gm. of fuchsin (magenta) in 100 cc. of water, then add caustic soda solution, drop by drop, until the fuchsin solution is decolorized; filter and preserve in a well-stoppered bottle. In applying the test with this reagent, the mixed fibres are treated with the hot solution, then well rinsed, when the animal fibres will be dyed red, the vegetable fibres remaining colorless. (4) Zinc Chloride Solution. Dissolve 1000 gms. of zinc chloride in 850 cc. of water, and add 40 gms. of zinc oxide, heating until complete solution is effected. (5) Stannic Chloride Solution. This may be prepared by dis- solving 15 gms. of stannous chloride (SnCl 2 ) in 15 cc. of concen- trated hydrochloric acid, then gradually adding 3 gms. of pow- dered potassium chlorate (KClOs). Dilute to 100 cc. with water. (6) Silver Nitrate Solution. 5 gms. of silver nitrate (AgNO 3 ) are dissolved in 100 cc. of water, and preserved in an amber- colored bottle. (7) Mercury Nitrate, Millon's Reagent. Dissolve 10 gms. of mercury in 25 cc. of nitric acid diluted with 25 cc. of water at a lukewarm temperature. Mix this solution with one of 10 gms. of mercury in 20 cc. of fuming nitric acid. QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 337 (8) Copper Sulphate or Ferric Sulphate. Dissolve 5 gms. of these salts respectively in 100 cc. of water. (9) Sodium Plumbite. Dissolve 5 gms. of caustic soda in 100 cc. of water and add 5 gms. of litharge (PbO), and boil until dissolved. (10) Ammoniacal Copper Oxide, Schweitzer's Reagent* Dis solve 5 gms. of copper sulphate in 100 cc. of boiling water, add caustic soda solution till the copper compound is completely pre- cipitated, wash the precipitate of copper hydrate well, then dis- solve in the least quantity of ammonia water. This gives a deep blue solution. (n) Ammoniacal Nickel Oxide. Dissolve 5 gms. of nickel sulphate in 100 cc. of water and add a solution of caustic soda until the nickel hydrate is completely precipitated; wash the pre- cipitate well and dissolve in 25 cc. of concentrated ammonia and 25 cc. of water. This solution dissolves silk almost immedi- ately, but reduces the weight of vegetable fibres only about \ per cent., and of wool only J per cent. (12) Caustic Potash or Caustic Soda. Dissolve 10 gms. of the caustic alkali in 100 cc. of water. (13) Sodium Nitroprusside. Dissolve 2 gms. of the salt in 100 cc. of water. (14) Lead Acetate. Dissolve 5 gms. of lead acetate crystals (sugar of lead) in 100 cc. of water. (15) Sulphuric and Nitric Acids. The commercial concen- trated acids are employed. (16) Chlorin Water. Water is saturated with chlorin gas obtained by acting on pyrolusite (MnO 2 ) with hydrochloric *B6ttcher recommends that this solution be prepared as follows: A glass tube about 2 inches in diameter and 24 inches in length is loosely filled with thin sheet copper and then filled up with ammonia water. After a few minutes, the liquid is drawn off, and then poured over the copper again. This process is repeated during several hours, when a deep-blue saturated solution of ammoniacal copper oxide is obtained. Neubauer recommends to precipitate a solution of copper sulphate with caustic soda in the presence of ammonium chloride; the precipi- tate so obtained is washed several times by decantation and finally on a filters It is then dissolved in the least quantity of ammonia water. Wiesner prepare, the solution by digesting copper turnings with ammonia water in an open flask. 33 8 THE TEXTILE FIBRES. acid. The solution should be preserved in amber-colored bottles. (i 7) lodin Solution. Dissolve 3 gms. of potassium iodide in 60 cc. of water, and add i gm. of iodin. Dilute this solution, before using, with 10 parts of water. When the reaction is employed in connection with sulphuric acid, the latter consists of 3 parts of concentrated sulphuric acid, i part of water, and 3 parts of gly- cerol. The glycerol has the effect of preventing injury to the fibres, and at the same time brings out certain details of the structure when the fibres have previously absorbed the iodin. The fibres are moistened first with the iodin solution and then with the sulphuric acid solution. (18) Picric Acid Solution. Dissolve 0.5 gm. of picric acid in 100 cc. of water. A delicate reaction * for detecting the presence of vegetable fibres in wool is the following: The sample of material under- examination is well boiled with water to remove any finishing materials that might be present and interfere with the reaction. Then a small portion of the sample is put in a test-tube with i cc. of water and 2 drops of an alcoholic solution of alpha-naphthol and about i cc. of concentrated sulphuric acid. If vegetable fibres are present, they will be dissolved and the liquid will acquire a deep violet color when shaken; the animal fibres only give a yellow to reddish brown coloration but no violet tint. If thymol is used instead of alpha-naphthol, a beautiful red coloration will be produced in the presence of vegetable fibres. Cross and Bevan have devised a delicate test which is serviceable for detect- ing the presence of vegetable fibres in fabrics: the sample of the cloth is immersed in a solution of ferric chloride and potassium ferrocyanide, when any vegetable fibre present will be colored blue. Lieberman gives a test to distinguish between animal and vegetable fibres as follows: The fibres are boiled with a solution of magenta which has previously been decolorized by the addi- tion of just sufficient caustic soda ; then they are well washed and * Molisch, Dingl. Polyt. Jour., 1886. QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 339 >, B 1 ll 1 | "S 1 l 1 l S ' I g 1 ^ I 1 B o _O TO 3 ^ 2 X! I s '1 .SP CO 1 I Jld "1 3 a 'o U "E| 8 | 1 i ?r ^ l l l s u 1 bC 1 1 W 11 i _O ,2 a "a; S s Q > ^ i CO if > u 'c | 3 j ^ a- x J I R l l l l f S i 1 3 3 4 * 1 Is CO 1 P o J PQ 1 1 . T3 g s 1 i 1 d 2 J 3 cr CU M H w P ca < 0) Swells up comes b 1 1 l l l l Dissolves in cold Dissolves out colo i S c/r 1 CO 1 1 H ^^ C/} HL '3 i C *ri cr C/} ^d CO CO TO H 1 CO CU "5* ^ 1 1 1 T_J CO j> Ji X G" ^ . >< M i c is | CO 1 EL 2 2 M x S2 n-J CO 1 CO 1 CO > l c P It L 1 1 1 1 8 CO "^ *O rt "o 8 ^ ^ "^ 'w TJ o 5 P > S > Q *" >H M >H p^ 1 : TJ UH digested in 16 cc. of cold water till swollen, and heated to complete solution. One-half of this latter solution is strained through a piece of fine muslin (the rest is discarded) and mixed with the solution of gum arabic; 10 to 12 cc. of glycerol are added, the whole is well mixed and warmed. It is best preserved in small bottles containing a fragment of camphor. On cooling the mixture solidifies, but when it is to be used the bottle is warmed, a small bundle of fibres for examination are tied together and saturated with the glue, drawing the fibres out carefully till they are straight and parallel. The bundle is then hung up and dried for 1 2 hours, after which it will be firm enough to cut with a microtome. The slices thus obtained are placed on a slide, and moistened with the iodin solution; this dissolves the glue, which is absorbed by strips of blotting-paper and thus removed. With soft fibres that are easily cut, a section may be more simply obtained by soaking in melted paraffin, and, after cooling, cutting on the microtome. The wax may be removed from the section by dissolving in benzene or turpentine. Table IV shows the reaction of the various vegetable fibres with the iodin-sulphuric acid reagent, together with the length and diameter of the ultimate fibre-cells in millimetres. Allen * summarizes in Table V the reactions to distinguish silk qualitatively from other fibres. 3. Distinction between Cotton and Linen. As it is often desirable to discriminate between these two fibres, the following tests, as suggested by various authorities, are given: (1) The fibre is burnt: Cotton burnt end tufted. Linen burnt end rounded. (2) The fibre is immersed in concentrated sulphuric acid for two minutes, washed well with water, then with dilute ammonia water, and dried: Cotton forms a gelatinous mass soluble in water. Linen the fibre is unaltered. * Commer. Org. Anal., vol. 4, p. 518. QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 343 11 I-S OM 1 1 O*- 9 -a fl J ti t3 l t rtW UU U t^OOOO 10 ^OOiOOO tOlO>-it~.. fOi i i i 1 f^WNCSfO OOOO|O||||| OOOOO dodo d ddddd OOOOO OOvONM Mi-iQ OOO odd WMNfO<^ OOOOO ddddd cs (N vO O O O M M M toOO fO i i i i i o o o o o o I I I I I o o o o o o OOOOO ddddd \O <*o^o to 10 O ^3" ^t* OOO O O O O O odd ddddd vr>O NOO^O iy} M M CS VO ^Illll OOOOOO){||| N t^ ^ OOioOO ^OO MWMWt-H OOO OOOOO odd ddddd IT) O\ to O to O to CO WMdCIM O K 11 ft 3 . ... : ; . bo.... i |li i ;| * "Hr^'" ** c/5**H* ^^ rt C ^ ^C "oiDq *4^^J 3^ * fc! OX^ oto'C^rf *- IjSillll -ai-jftl ^'S N S|B| jj o'S 3 5* 8 B S 2 S J9 . S rt M 1 Q..& -S 6 J3 Eaa^;upH^^u BiwliU WC^PH ^ ' CO i!r> PO M 00 4 o o Sffl " H N M (N cs ^, O 0* d -0 CO ^ ^o H vo M <^o ^J" ^ s t> p k x 1 PO AN 1 i 1 I >!o ^ i o * 1 o sj o o o 2j CO ffL l-O M 1*3 o Fr| I jj I 1 1 i!o H to 5 - 10 M M ^ CO r-i ^ fe u Reaction witl Anilin Sulphate. Remains u ] colored Faint yellow ^o e 33 O Egg-yellow Golden yello Uncolored Uncolored ' 12 1 1 1 1 u II a, e 'C bo 3 'lie t] ^1-g Reaction with and Sulphuric i 3 Greenish blue t blue Yellow to brow Rusty red Reddish brown s. g - >^ 2 1 CJ 4 flj |l is ! !-! Reaction with Schweitzer's Reagent. Soon attacked and en- most entirely dis- solved 1 'O vfl C U Bluish color; more or less distinct swelling g 4-> . b PQ s ! I 1 Bluish color; more or less swelling When "cottonized" quickly acted upon, and almost com- pletely dissolved 4 bo q 13 e V-f * bC "8| "o . 1 li la K cx a 1 0) 1 % jrt&H 1 cd 3 5 C/3 * 1 ^ a a amie ' J5 P4 K PH M ^ u PN U < ^ 350 THE TEXTILE FIBRES. si ( -8 1 3|-2 I S. 2 SiiH SB B 8 -^ vfl > S II 3 - ^& - ^^> eti I to U -o s -o co cd Kg |X ^ .2 'd be " K S^ s QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES, 351 siderable success, though confirmatory tests should be applied to the detection of each fibre indicated. The differentiation be- tween the various vegetable fibres given is especially difficult. 8. Identification of Artificial Silks. In Table VIII are given Hassac's tests to identify the different varieties of artificial silks or forms of lustra-cellulose, and also the distinction between these latter and true silk. 9. Distinction between True Silk and Different Varieties of Wild Silk. True silk (from Bombyx mori) rapidly dissolves (one- half minute) in boiling concentrated hydrochloric acid; Senegal silk (from Faidherbia) dissolves in a somewhat longer time, while yama-mai, tussah, and cynthia silks require a much longer time for complete solution. True silk is also rather easily soluble in strong caustic potash solution, whereas the other varieties of silk are not. The most approved reagent, however, for sepa- rating true silk from the wild varieties is a semi-saturated solution of chromic acid, prepared by dissolving chromic acid in cold water to the point of saturation and then adding an equal volume of water. True silk is completely dissolved on boiling in this solution for one minute, whereas wild silk remains insoluble. Under the microscope true silk can readily be told from wild silks, as the latter fibres are broad and flat, and show very dis- tinct longitudinal striations, which are absent in true silk. Excep- tion must perhaps be made with the wild silk from Saturnia spini, which can scarcely be told from true silk by a micro- scopical examination. With regard to distinguishing between the different varieties of wild silks themselves, some* valuable information may be gained by a determination of their relative diameters. Hohnel gives the following values for the greatest thickness of the different silks: True silk (Bombyx mori) 20 to 25 ft Senegal silk (Faidherbia bauhini) 30 to 35 p Ailanthus silk (Attacus cynthia) 40 to 50 fi Yama-mai silk (Anther aa yama-mai) 40 to 50 fi Tussah silk (Bombyx selene) 50 to 55 ft Tussah silk (Bombyx mylitta) 60 to 65 // According to Wiesner and Prasch, the breadths of the single fibres of different silks are as follows: 35 2 THE TEXTILE FIBRES. TABLE VIII. IDENTIFICATION OF ARTIFICIAL SILKS. Reagent Natural Silk. Collodion Silk. Cellulose Silk. Gelatin Silk. Water No change Swell up; addition of alcohol or glycerin causes contraction again Cone, sulphuric acid Swells rapidly and d i s - solves Gradually be- comes thin- ner and dis- solves Only dissolves on heating Acetic acid Slight swell- ing Slight swell- ing Dissolves o n boiling Half-saturated sol. of chromic acid Dissolves slow- iy Dissolves in the cold Diphenylamin and sulphuric acid Blue color _ Caustic potash, 40% Dissolves with- out color Swell without dissolving, but color liquid yellow Dissolves rap- idly Ammoniacal cop- per solution Swells quickly and dis- solves Swells slowly and d i s - solves Insoluble; col- ors liquid violet Alkaline copper glycerin solu- tion Dissolves im- mediately at 80 C. tus- sah silk dis- solves in one minute o n boiling Unchanged Unchanged Dissolves o n boiling lodin in potas- sium iodide An intense red color which disappears on washing lodin and sul- phuric acid Yellow Deep violet- blue Pure blue Yellowish t o reddish brown lodin in zinc chloride Becomes yel- low and dis- integrates Blue- violet Gray-blue to gray-violet Becomes yellow and disinte- grates Ignition Odor of burnt feathers No odor No odor Odor of burnt feathers QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 353 Ailanthus silk 7 to 27, mostly 14 /* Yama-mai silk 10 to 45, mostly 23 /* Bombyx mylitta 14 to 75, mostly 42 ft Bombyx selene , . . 27 to 41, mostly 34 fi Senegal silk 12 to 34, mostly 22 ft True silk 9 to 2 1, mostly 13 ft True silk, ailanthus silk, and Senegal silk do not show any cross-marks, or only very faint indications of such ; whereas with tussah silk and yama-mai silk the cross-marks are very distinct and characteristic. The microscopical appearance of the end of the fibre on being torn apart also serves at times as a useful means of distinguishing the variety of silk; true silk, tussah silk, and yama-mai silk show scarcely any fraying at the ends; in Senegal silk the fraying is very noticeable in almost every fibre; while in ailanthus silk about one-half of the number of fibres show a frayed end.* * Besides the wild silks mentioned above, there are a few others of lesser im- portance, which for the sake of completeness are herewith described : 1. Saturnia polyphemus, a North American variety, consists of very flat fibres, with large air-canals and numerous structural filaments separating at the edge of the fibre; coarse lumps of adhering sericin are frequent; well-defined cross-marks are also frequent. The single fibre is about 33 fi in width; in its polariscopic appearance these fibres very much resemble ailanthus silk. 2. Arryndia ricini: the fibres are even more flattened than the preceding and resemble a thin band or ribbon; large air-canals are of frequent occurrence; striations very apparent; the sericin layer is in places very thin, and sometimes apparently lacking altogether. The double fibre is about 45 to 55 fi in width, and 4 to 6 fj. thick. At the edge of the fibre frayed ends of structural filaments are often apparent. Cross-marks are rather ill-defined, but of frequent occur, rence. The sericin layer, though thin, is quite uniformly developed. 3. Anther &a pernyi has a very flat fibre, resembling a ribbon; it does not fray out at the ends, and shows scarcely any single filaments. The double fibre measures 60 to 80 /* in width and 8 to 10 ^ in thickness. Cross-marks are rather few and indistinct. The seriein layer is very thin, and in general hardly notice- able. Moderately sized air-canals are present. 4. Saturnia cecropia occurs in Texas. The fibre is also flat and ribbon-like in form; the double fibre measures 60 to 90 p. in width and 10 to 15 fj. in thick- ness; air-canals are frequent and large, hence the fibre usually appears rather dark under the microscope. The cross-marks are very distinct, and at such points the fibre is much broader. The fibre is usually much frayed out and indi vidual filaments are easily distinguished. The sericin layer is quite thin, but very uniform. 5. Attacus lunula has fibres which are not so flat as the preceding. The double fibre is 25 to 35 /x in width and 12 to 18 fi in thickness. The air-canals 354 THE TEXTILE FIBRES. By the use of the polariscopic attachment to the microscope, considerable differences can be observed in the interference colors displayed by the different varieties of silks. It is best to conduct these observations under a magnification of 30 to 50 diameters; and as the silk fibres are more or less ovoid in section, it must be borne in mind that the same fibre will give a different color phe- nomenon, depending on whether it is viewed from the narrow side or from the broad side. Hence, to obtain trustworthy results, the appearance of the same side only of the fibres should be com- pared. Also, the appearance of single fibres only, and not of crossed fibres, should be taken. Hohnel gives the following description of the appearance of the different silk fibres viewed in polarized light, the observations being made with a dark field, and under a magnification of 30 to 50 diameters : 1. True silk: (a) broad side, very lustrous, of a bluish or yel- lowish opalescent white; the same color is nearly always to be found over the entire breadth; (b) narrow side, exactly similar to the preceding. 2. Yama-mai silk: (a) broad side, generally of a pure bluish opalescent white; also darker bluish to almost black tones; nearly all of the colors are brilliant; (b) narrow side, shows all colors, very brilliant and contrasted; darker and blackish tones also occur. 3. Tussah silk (from Bombyx selene): (a) broad side, shows all colors, very brilliant; thickness of the fibre very uneven, hence the colors change through the length; the thick parts are dark blue and reddish violet, while the thinner parts are yellow or orange; (b) narrow side, shows bright red and bright green colors, though often but slightly visible; the colors form long flecks ; often only dark gray to black. 4. Tussah silk (from Bombyx mylitta): (a) broad side, a bluish opalescent white prevailing; also brown, gray, and black tones; the colors occur in flecks like preceding, though scarcely are fine and delicate; and the fibre shows but a slight degree of fraying. The sericin layer is very thin and finely granulated on the surface; in places it has the form of irregular shreds. The fibre as a whole has a brownish yellow appear- ance, due to the ochre-yellow color of the sericin layer. QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 355 even dark blue, but mostly bright orange to red or brown; (b) narrow side, color a dull gray with bright red or green flecks; the general appearance is very similar to the preceding silk. 5. Ailanthus silk: (a) broad side, bright yellow or yellow- brown to gray-brown colors; (b) narrow side, nearly all colors, but rather soft and not very contrasted, seldom very bright, but rather dull; short flecks of green, yellow, violet, red, or blue. 6. Senegal silk: (a) broad side, bright yellowish white, gray to brown, seldom bluish white in color; (b) narrow side, faint and dull gray, brown to blackish colors, seldom bright colors. 10. Micro-analytical Tables. The following micro-analytical tables have been adopted from Hohnel for the qualitative deter- mination of vegetable fibres: I. TABLE FOR THOSE VEGETABLE FIBRES BOTANICALLY DESIGNATED AS HAIR STRUCTURES. 1. (a) Each single fibre consists of a single cell (see 4). (b) Each fibre consists of two cells, namely, a short, thick, underlying cell, and an overlying pointed, principal cell. The fibres are grayish brown, scarcely 0.5 cm. long; hard, woolly, lifeless, thin-walled, but round-stapled. Such fibres form the thick upper coating on the leaves of the Cycadce macrozamia of New South Wales, and are used as vegetable hair in upholstery. (c) Each single fibre consists of a series of cells, hence is a cellular fibre. The cells are golden yellow to brown in color, generally clinging together, and empty. The fibre as a whole is highly lustrous, but very harsh and brittle; very thin- walled, flat, and ribbon-shaped; frequently twisted on its axis; broad and 0.5 to 2 cms. long. Such fibres form the thick coating on the leaves of various ferns (Cibotium) in Asia, Australia, and Chili. The material is used for upholstery under the name of pulu. (d) Each fibre consists of numerous cells growing side by side, or of several series of such; forms the so-called tuft (see 2). 2. (a) Hairs straight, stiff ; white to dirty yellow in color.. (see 3). (b) Hairs woolly, tough, brownish violet in color, 4 to 6 mm. long; consisting of long cotton-like, flat, twisted, spiral cells, 35 6 THE TEXTILE FIBRES. the walls of which are frequently thick and undulating; the con- tents of the cells moderately abundant, yellow to violet, and in part colored red with hydrochloric acid. This fibre covers the small, egg-shaped, flattened fruit of the new Holland plant FIG. 112. The Lesser Cotton Grass (Eriophirum latijolium). (After Dodge.) Cryptostemma calendulaceum. It is used in Australia as a stuffing material. (c) Hairs woolly, harsh, reddish yellow in color; the cells are very thin- walled, colorless, and generally empty; in places, how- ever, filled with a homogeneous reddish yellow substance; where two cells come together side by side there are to be noticed round spots. The individual cells are relatively broad, extremely varied. QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 357 and irregularly thick; irregularly bent in places and frequently knitted together. This fibre forms the coating of a plant (Hibis- cus?) growing in Cuba; as employed for upholstery materials it goes by the name of Majagua. FIG. 113. Cotton Grass (Eriophorum an gusli folium). (After Dodge.) 3. (a) The hairs are i to 3 cm. long, and on the average are under 50 jj. wide; they consist of two layers of cells which grow into one another. The inner walls are rough; the outer walls are thin and indented, hence lie close against the inner portion; the sec- tion walls are quite noticeable and thick; the tufts end in 2 to 6 pointed, often hook-shaped cells; the end cells show numerous pores; weakly lignified. This fibre consists of the ripe fruit 35 8 THE TEXTILE FIBRES. spicula of cotton-grass, Eriophorum angusti folium, E. latijolium, etc Cotton-grass (see Fig. 1 14). (b) The fibres are 5 mm. long; mean breadth of the tufts 8 to 1 6 fi, the widest being under 30 /*; the tufts do not end with sharp-pointed cells; the section- walls under low magnification appear as little knots and are usually quite noticeable. This fibre is obtained from the small, lance-like fruit of the reed mace, Typha anguslijolia, which grows on a small shaft, and FIG. 114. Fibres of Cotton Grass or Vegetable Silk. ( X5o.) The sharp fractures show the brittle nature of the fibre. (Micrograph by author.) carries the hairs on the other end. It is used for upholstery and other filling material Reed-mace hair (see Fig. 115). 4. (a) The fibres are flat, woolly, frequently twisted in a spiral manner on their axes; not lignified (see 5). (b) The fibre is generally cylindrical, stiff, not twisted; some- what lignified, hence colored red with indophenol or phloro- glucol (see 6). 5. (a) Fibres i to 5 cm. long; white to yellowish brown; 12 to 42 fj. thick Cotton (see Fig. 116). (b) Fibres only 9.5 cm. long; very thin; usually consisting of tufts; violet-brown in color. See above, under 2 (b). Cryptostemma hairs. 6. (a) The product consists of grassy spicula with a hairy cover- ing; the hairs are 5 to 8 mm. long and about 10 to 15 /* wide; the thickness of the wall of the thick, cylindrical-pointed hairs QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 359 remains rather uniform up to the point itself, hence the latter ap- pears very thick; spots are often observed. This fibre is upholstery material from Saccharum officinale Sugar-cane hairs. (b) The product consists of short white fibres, about 8 to 24 // in width, and of oval, flat fruit-shells, 4 mm. wide and 5 mm. long; the hairs are broadened at the base, hence generally knife-shaped; thick- walled, with transverse, fissure-like marks; the upper portion of the hair is very thin and rough- walled; colorless; the ends are usually blunt and contain a granular matter; slightly lignified, especially at the base. Poplar cotton. (c) The product consists entirely of hairs and is almost entirely free from accidental impurities Vegetable down and silk. 7. (a) The fibres have two to five longi- tudinal ridges on the walls, which are either crescent-shaped or quite flat, running into network at the base; these ridges are broad and difficult to discern in a surface view of the fibre, yet sometimes very apparent ; the maximum thickness about 35 //; white or yellowish in color. These fibres are the seed-hairs of Apocyneen and Asclepiadeen. Vegetable silk (see Fig. 119). (b) The fibres are without ridges; trans- verse ridges frequently at the base or as a network. Maximum thickness generally under 35 //; yellowish to brown. These fibres consist of the hairs which cover the fruit-pods of Bombaca. Vegetable down (see 13). 8. (a) The hairs are 3.5 to 4.5 cm. long, and the largest are 50 to 60 // in diameter (see 9). (b) The fibres are 1.5 to 4 cm. long, and the largest are 35 to 45 fi in diameter (see 10). FIG. 115. Reed-mace Hair. (X34O.) (Hoh- nel.) A, poition of hair; B, ripe fruit at/; h, hair around fruit; 2, cells ; k, knotted struc- ture. 3 6 THE TEXTILE FIBRES. 9. (a) The fibres are narrowed at the base, and directly above are strongly swollen, and up to 100 /z in thickness; numerous pores at the base; the.fibres grow brush-like on a stem, are yel- lowish and harsh. This is vegetable silk from Senegal. Strophantus (see Fig. 117). FlG. 116. Cotton Fibres. (X34Q.) (Hohnel.) a, portion swollen with Schweitzer's reagent; cf, shreds of cuticle; cr, rings of cuticle; ce, cellulose; i, dried protoplasmic canal; 6, various cotton fibres with sections above; 7, lumen; d, twists; 5, granulations on cuticle. (b) The fibres are white, firm, and tough, not harsh; form a hairy tuft or crown. This is vegetable silk from India, Beaumontia grandi flora (see Fig. 118). QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 361 (c) Yellow rod fibres, weak, stiff, straight, and harsh. Calotropis procera, Senegal. 10. (a) At base of the hair there are spots or pores... (see n). (b) Spots or pores lacking. Vegetable silk from Asclepias cornutii, curassavica* etc (see Fig. 119). 11. (a) Spots large; round or oblique; the walls of the fibre are not thicker at the base than at the upper portion; the ridges on FIG. 117. Fibre of Strophantus. ( X3oo.) a, longitudinal view; b, cross-section. (Micrograph by author.) the fibre are remarkably well developed, the hairs are strongly bent back at the base. Vegetable silk from Calotropis gigantea. (b) Spots small, no longitudinal markings; walls thicker than the foregoing fibre; ridges less noticeable and often apparently lacking (see 12). 12. (a) Hairs narrowed at the base Hoy a viridi flora. (b) Hairs not narrowed at all, or scarcely so Marsdenia, 13. (a) The hairs have mesh-like ridges at the base situated obliquely, or have spiral ridges (see 14). (b) Without mesh-like ridges at the base (see 15). 14. (a) Base broader, thin-walled, with oblique, mesh-like ridges or spiral swellings, which often extend to a considerable dis- tance. Points very thin-walled, gradually tapering, not ended sharply; frequently containing a reddish-brown homogeneous granular substance; fibre not very stiff, usually notched. Base * This plant grows in tropical and sub-tropical America and is also found in India. Its seed-hairs are said to be stronger than those of most other varieties of such fibres. 362 THE TEXTILE FIBRES. contains no marrow. Vegetable down from Eriodendron anjrac- tuosum. (b) Quite similar, but the ends are not so tapering; without FlG. 118. Vegetable Silk from Beaumontia grandiflora. (X34O.) (Hohnel.) b, base of fibre; s, pointed ends; q, cross section; m, middle portion of fibre; w, cell -wall; /, longitudinal ridges. marrow; whole fibre somewhat rough- walled. Vegetable down jrom Bombax heptaphyllum. (c) Very similar to (a), but walls of fibre are quite roughened and contain at intervals throughout its length a granular marrow; base thick-walled, mesh-like fibrous ridges, but neither spirally developed nor very broad at most only one-sixth of the width QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 363 of the fibre; ends, as before, thick- walled. Vegetable down, Ceiba cotton, from Bombax ceiba (see Fig. 1 20). FIG. 119. Vegetable Silk from Asclepias cornutii. (Xsoo.) a, longitudinal view; 6, cross-sections; r, thickened ridges; w, cell- wall. (Micrograph by author.) 15. (a) Raw fibre, brown, rough- walled; walls i to 7 n thick; not indented; points without marrow; stiff and very sharp at FIG. 120. Vegetable Down (Bambax ceiba). (X^oo.) (Micrograph by author.) nd ; base not broadened, often contains granular matter Vege- table down from Ochroma lagopus (see Fig 121). 3 6 4 THE TEXTILE FIBRES. (b) Raw fibre, yellowish, thin-walled, walls very uneven in thickness ; frequently weakly developed longitudinal ridges ; just at the base the wall is very thick. Vegetable down from Cochlospermum gossypium. II. GENERAL TABLE FOR THE DETERMI- NATION OF THE VEGETABLE FIBRES. Including cotton, as well as the more important fibres derived from bast or sclerenchymous tissues. A. Fibres Colored Blue, Violet, or Greenish with lodin and Sulphuric Acid. (a) BAST FIBRES AND COTTON. (Cot- ton, flax, hemp, sunn hemp, ramie, Roa fibre.) I. The cross-sections become blue or violet with iodin and sulphuric acid; show no yellowish median layer; the lumen is often filled with a yellowish marrow. i. Cross-sections: they occur either FIG. i2i.Ochroma lagopus. singly or in small groups; the single (X34Q.) (Hohnel.) m, sect i ons d o not j o in over one another; middle part of fibre; b, base; . 111 i i 5, pointed end; /, lumen; q , are polygonal, and have sharp edges; cross-section; -w, cell-wall. iodin and sulphuric acid colors them blue or violet; they show closely packed, delicate layers; the lumen appears as a yellow point. Longitudinal appearance: with iodin and sulphuric acid, quite blue; it appears transparent, quite uniformly thick; smooth or delicately marked; joints frequent; indications of dark lines running through, which are usually crossed; enlargements on the fibre, especially at the joints, frequent; the lumen appears as a narrow yellow line; the natural ends of the fibres are sharply pointed; length 4 to 66 mm., thickness 15 to 37 u. Linen or Flax. QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 365 2. Cross-sections single or very few in a group, loosely held together; polygonal or irregular, mostly flat, very large; colored blue or violet with iodin and sulphuric acid; stratification not noticeable; the lumen is large and irregular; frequently filled with a dark yellow marrow; radial fissures frequently apparent. Longitudinal appearance: many of the fibres remarkably broad; the width of a single fibre very uneven; smooth or striped; very often ruptures in the wall; with iodin and sulphuric acid, blue or violet ; the lumen readily seen ; very broad, often contain- ing a dark yellow marrow; joints noticeable; dark, transverse lines frequent, often crossing each other; the ends are relatively thick- walled and blunt; length 60 to 250 mm., thickness up to 80 jj. China grass, Ramie. 3. Cross-sections: not many in the groups ; polygonal; mostly with straight or slightly curved sides and blunt angles; the lumen is contracted lengthwise regularly; frequently contains a yellow marrow, many sections are surrounded by a thin, green- ish-colored layer; not closely joined to one another. The sec- tions often show very beautiful radial marks or fissures and con- centric layers; the various layers are colored differently. Longitudinal appearance, as with China grass ; proportional dimensions similar Roa fibre. 4. Cross-sections always isolated, rounded, various shapes, mostly kidney- shaped ; with iodin and sulphuric acid, blue or violet; lumen contracted, line-shaped, often containing a yel- lowish marrow; no stratification. Longitudinal appearance: fibres always separate; with iodin and sulphuric acid, a fine blue; streaked and twisted; lumen broad, distinct, frequently contains yellowish marrow; ends blunt ; the entire fibre not soluble in concentrated sulphuric acid; coated with a very thin cuticle; length 10 to 60 mm., breadth 12 to 42 /* Cotton. II. Cross-section blue or violet with iodin and sulphuric acid; polyhedral, rounded or irregular; always surrounded by a yellow median layer. i. Cross-sections always in groups, with angles more or less rounded off, lying very close to one another; all of them sur- 366 THE TEXTILE FIBRES. rounded by a thin, yellowish median layer; the lumen is line- shaped, single or forked, often broad, with inturning edges, with- out marrow; good concentric stratification; the different strata being differently colored. Longitudinal appearance: with iodin and sulphuric acid, blue, greenish, or dirty yellow; fibres irregular in thickness, fre- quently with appended portions of yellowish median layer; joints FIG. 122. Hemp. (X340.) (Hohnel.) b, ends of fibres; c, cross-section; d, longitudinal view. and transverse lines frequent; stripes very distinct; the lumen is not very apparent, but broader than linen; ends are broad, thick- walled, and blunt, often branched; length 5 to 55 mm., breadth 16 to 50 fj. Hemp (see Fig. 122). 2. Cross-sections in large groups, lying very close together and touching; very similar to those of hemp; often crescent-shaped. Polygonal or oval, with lumen of varying size, frequently contain- ing yellowish marrow; lumen usually not line-shaped, but irregu- lar; a broad yellow median layer always present, from which the blue inner strata are easily distinguished; stratification very dis- tinct, as with hemp. QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 367 Longitudinal appearance, as with hemp, except in dimen- sions, which are: length 4 to 12 mm., breadth 25 to 50 ft. Sunn hemp. (6) LEAF FIBRES. (With vascular tissue; without jointed structure. Esparto and pineapple fibre.) FIG. 123. Esparto-grass. (X340.) (Hohnel.) s, short sclerenchymous elements; /, cells; /, fibres; h, hairs; e, epidermal cells. i. Cross-sections in large, compact, often crescent-shaped groups; very small; pale blue or violet with iodin and sulphuric acid; surrounded by a thick, shell-like network of median layer; rounded or polygonal; lumen like a point or streak; thick cut- tings appear greenish or even yellow; frequently bundles of vascular tissue with one or two rows of thick, yellow-colored fibres. Longitudinal appearance: Fibres slender, regular, very thick- walled, smooth; lumen often invisible, generally as a fine 368 THE TEXTILE FIBRES. line; ends are tapered with needle-like points; color with iodin and sulphuric acid, blue, often but slightly pronounced; frequently present short, thick, stiff, completely lignified fibres from vascular tissue; length 5 mm., breadth 6 p. Pineapple fibre. 2. Cross-sections in groups; with iodin and sulphuric acid, mostly blue, though also yellow; often with pronounced stratifi- cation; the outer strata frequently yellow, while the inner are blue; rounded or oval, seldom straight-sided; lumen like a point. Longitudinal appearance: the fibres are short; blue with iodin and sulphuric acid; thin, very firm, smooth, uniform in breadth; lumen yellow, line-shaped; ends are seldom pointed, mostly blunt or chiselled off, or forked; length 1.5 mm., breadth 12 fj. Esparto (see Fig. 123). B. Fibres Colored Yellow with Iodin and Sulphuric Acid. (a) DICOTYLEDONOUS FIBRES. (Without vascular bundles; lumen showing remarkable contractions. Including jute, Alel- moschus, Gambo hemp, Urena, and Manila hemp; the latter sometimes shows vascular tissue.) I. Cross-sections in groups; polygonal and straight-lined, with sharp angles; lumen round or oval, smooth, and without marrow; cross-sections with narrow median layers showing the same color as the inner strata with iodin and sulphuric acid; lengthwise appearance shows the lumen with contractions. 1. Cross-sections polygonal, straight-lined; lumen, in general, large, round, or oval. Longitudinal appearance: fibres smooth, without joints or stripes; lumen distinctly visible; broad; with contractions; the ends always blunt and moderately thick; ends have wide lumen; length 1.5 to 5 mm., breadth 20 to 25 /* Jute. 2. Cross-sections in general somewhat smaller than jute; sides straight, with sharp angles; lumen frequently like a point or line, oval, occasionally pointed; not so large as with jute. Longitudinal appearance: fibres quite even in thickness, smooth, with occasional joints or stripes; lumen narrow, irregu- lar in thickness, contractions frequent; the ends are broad, QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 369 blunt, frequently thickened; length i to 1.6 mm., breadth 8 to 20 // Pseudo-jute or Musk mallow of Abelmoschus. II. Cross-sections in groups, lying close together; polygonal, with sharp lines and sharp or rounded angles; lumen without marrow; the median layer is broad, and with iodin and sul- phuric acid is colored perceptibly darker than the inner layer of cell- wall; the lumen in places is completely lacking. 1. Cross-sections more or less polygonal, with sharp or slightly rounded angles; the lumen is small, becoming broader and more oval as the section is more rounded; the median layer is broad, and is colored considerably darker than the cell-wall with iodin and sulphuric acid; stratifi- cation occasional and indistinct. Longitudinal appearance: the fibres vary much in thickness; lumen generally narrow, with de- cided contractions, and in some parts totally absent; the broader fibres often striped; ends are blunt and generally thickened; length 2 to 6 mm., breadth 14 to 33 fj. Gambo hemp. 2. Cross-sections always in groups; small, polygonal, with sharp angles; lumen very small, appearing as a point or a short line. Longitudinal appearance: occasionally jointed or striped; lumen with decided contractions, in some places altogether lack- ing; ends blunt and sometimes thickened; length i.i to 3.2 mm., breadth 9 to 24 //. Pseudo-jute from Urena sinuata (see Fig. 124). (b) MONOCOTYLEDONOUS FIBRES. (Occurring as vascular bundles together with bast; the lumen exhibits no contractions; FIG. 124. Pseudo-jute (Urene sinu- ata}. (X34Q.) (Hohnel.) ^longi- tudinal view; v, interruption of lumen; e, end with thick wall; q, cross-section; m, median layer; L, small lumen. 370 THE TEXTILE FIBRES. in Manila hemp vascular bundles often lacking. Includes New Zealand flax, Manila hemp, Sansevieria or bowstring hemp, Pita hemp, and Yucca fibre.) I. Cross-sections generally rounded, occasionally polygonal; the lumen is always rounded, without contractions longitudinally; median layer indistinct, or only as a narrow line; vascular tissue small in amount, or altogether lacking. 1. Cross-sections small, generally rounded, lying loosely sepa- rated; very rounded angles; lumen small, round, or oval, without marrow. Longitudinal appearance: the fibres are stiff and thin; the lumen is small but very distinct, and uniform in width; the ends are pointed; no markings and no joints; length 5 to 15 mm., breadth 10 to 20 /* New Zealand flax. 2. Cross-sections polygonal, with rounded angles, in loosely adherent groups; lumen large and round, often containing yellow marrow. Longitudinal appearance: fibres uniform in diameter; walls thinner than those of New Zealand flax; lumen large and distinct; ends pointed or slightly rounded; silicious stegmata adhering to the fibre-bundles and to be found in the ash as bead- like strings, insoluble in hydrochloric acid; length 3 to 12 mm., diameter 16 to 32 fj. Manila hemp. II. Cross-sections polygonal; lumen large and polygonal, with angles quite sharp; median layer lacking or only in the form of a thin line. 1. Cross-sections distinctly polygonal, often with blunt angles, lying compactly together; lumen large and polygonal, with sharp angles; no stratification in cell- wall. Longitudinal appearance: fibres thin and smooth; lumen large and distinct; ends pointed; length 1.5 to 6 mm., diameter 15 to 26 fi. Sansevieria fibre. 2. Cross-sections polygonal, not many sections to a group, but lying compactly together; angles slightly rounded; lumen not very large, polygonal, often having blunt angles; besides the bast-fibre sections are to be noticed some vascular bundles in the form of large spirals. QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 371 Longitudinal appearance: fibres uniform in diameter; lumen not very large, but uniform; no structure; ends pointed and sometimes blunt; length 1.3 to 3.7 mm., diameter 15 to 24 jj.. Aloe hemp. 3. Cross-sections polygonal, with straight lines; angles sharp, though sometimes blunt; sections lie compactly together; lumen large and polygonal, though angles not so sharp. Longitudinal appearance: fibres stiff, and often very wide towards the middle; lumen large; ends broad, thickened, and often forked; large, shining crystals to be found in the ash, which FIG. 125. Yucca Fibre. (X4OO.) A, longitudinal view; B, cross-section; m, median layer; /, transverse markings. (Micrograph by author.) are derived from the chisel-shaped crystals of calcium oxalate clinging to the outside of the fibre; these crystals are often J mm. in length; length of fibre i to 4 mm., diameter 20 to 32 /*. Pita hemp. III. Cross-sections polygonal and small, sides straight, with very sharp angles; lumen small, usually as a point or line-shaped; sections lie compactly together and are surrounded by a thick, distinct median layer. i. Cross-sections as above. Longitudinal appearance: fibres very narrow; lumen also very narrow; longitudinal ridges frequent; ends usually sharp- pointed; length 0.5 to 6 mm., diameter 10 to 29 /*. Yucca fibre (see Fig. 125). 37 2 THE TEXTILE FIBRES. C. Analytical Review of the Chief Vegetable Fibres. 1. Those occurring as thick, fibrous bundles, also with vascu- lar tissue (monocotyledonous fibres) (see 2). Vascular tissue absent; sections and fibres always single; round or kidney-shaped by being pressed together; fibres with a thin external cuticle insoluble in concentrated sulphuric acid, and not swelling (vegetable hairs) (see 7). Vascular tissue absent ; the fibres are bundles of bast fila- ments; sections occurring two or more together (mostly true dicotyledonous fibres) (see 13). 2. Lumen very narrow, line-shaped, much thinner than the wall (see 3). Lumen in thickest fibres almost as wide, or even wider, than the wall; completely lignified (see 4). 3. Sections polygonal, sides straight, with sharp angles; com- pletely lignified; diameter 10 to 20 ft. .Yucca fibre (see Fig. 125). Sections rounded to polygonal; often flattened or egg- shaped; the inner strata at least not lignified; diameter 4 to 8 p. Pineapple fibre. 4. Thick, strongly silicified stegmata occurring at intervals on the fibre-bundles in short to long rows, sometimes but few ; these are four-cornered, have serrated edges, and show a round, bright, transparent place in the middle; they are easily seen after the fibre has been macerated with chromic acid, and are about 30 /z in length; in the ash of fibres previously treated with nitric acid, they appear in the form of pearly strings, often quite long, and insoluble in hydrochloric acid; they are joined together length- wise; the fibres are thick- walled, with fissure-like pores; 3 to 12 mm. long; the fibre-bundles are yellowish and lustrous. Manila hemp. Stegmata present, sometimes in small, sometimes in large quantities; they are lens- shaped, small (about 15 /* wide), and are fastened to the exterior fibres of the bundles by serrated edges; in the ash of the fibre they melt together in the form of indistinct globules; in the ash of fibres previously boiled in nitric acid they QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 373 appear as yeast-cells, joined together in round skeletons of silica; the fibres are often thin- walled, with numerous pores; i to 2 mm. in length; the raw fibres generally brown and rough Coir. Stegmata absent, hence the fibres are not accompanied by silicified elements (see 5). 5. Fibre-bundles covered externally at intervals with crystals of calcium oxalate, at times up to 0.5 mm. in length; lustrous, with quadrangular sections, chisel-shaped at the ends, hence they appear as thick, needle-shaped crystals; when present in large numbers these crystals occur in long rows which are frequently visible to the naked eye, and always easily recognizable under the microscope, especially in the ash. The fibre-bundles are mostly thick, and their outer fibres (as a result of their preparation) frequently contain fissures or are torn; thickness of the walls very uneven; fibres often much widened at the middle. Pita hemp. Without crystals, generally thin; in cross-section usually less than 100 fibres to a bundle; thickness of walls and lumen very uniform (see 6). 6. Sections mostly round, not very compact; lumen usually thinner than the wall, but never a single line; in section round or oval; vascular tissue in but small amount New Zealand flax. Sections, on one side at least, polygonal; section of lumen polygonal, with angles more or less sharp; generally as wide or wider than the wall; vascular tissue frequent. Aloe hemp. 7. Fibres mostly rope-shaped, twisted, externally streaked, generally possessing fine granules or marked with little lines, therefore rough; thin to thick walls; cross-sections squeezed together, or round to- kidney-shaped, hence the fibre has more or less the shape of a flat band; section of lumen more or less arched, line-shaped, frequently containing yellow marrow; con- sists of pure cellulose with the exception of the thin cuticle. Cotton. Fibres not twisted, smooth externally, and without longi- tudinal markings; fibres not flat, sections round; walls generally 374 THE TEXTILE FIBRES. very thin; sometimes, however, they are thick; lignified, scarcely swelling in ammoniacal copper oxide . . . Vegetable down | Vegetable silks j ^ 8. Fibres on the inside possess from 2 to 5 broad ridges, which at times are very noticeable, at others scarcely visible; they run lengthwise in the fibre, and in section are semicircular; on this account the walls appear unequal in thickness when viewed ongitudinally; the maximum thickness is about 35 //. Vegetable silks (see 9). Fibres without ridges; maximum thickness mostly 30 to 35 // Vegetable down (see 12 ). 9. Largest diameters 50 to 60 ^; length 3.5 to 4.5 cm. . (see 10). Largest diameters 35 to 45 /*; length 1.5 to 4 cm. .(see n). 10. Fibres contracted at the lower end, and directly above abruptly swelling, becoming 80 /* thick; the under portion of the swollen area contains numerous pore-canals; fibres feather-like or brush-like, arising from a straight shaft. Vegetable silk jrom Sengal. Contrary to the above the fibres originate from one point, like a fan; remarkably strong, curved backwards; very firm. Vegetable silk from India. Like the foregoing, but the fibre is stiff, straight, weak, and brittle Calotropis procera. 11. Thickened ridges very noticeable; in the cross-sections often occurring in the form of a semicircle; bound together in a strictly reticulated manner. Vegetable silk from Asclepias cornutii. Thickened ridges indistinct, projecting but slightly in the cross-section Vegetable silk from Asclepias curassavica. 12. Raw fibre, yellowish; broadened at the lower end (up to 50 /*); also reticular thickening or transverse markings; wall i to 2 jy. thick. Bombax cotton. Raw fibre, brown; the lower end contracted and not showing reticulated thickenings; fibre almost altogether thin- walled, though just at the lower end very thick- walled. Cochlospermum gossypium. 13. Thick fibre-bundles, whose outer surface contains at inter- QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES. 375 vals series of thick -silicious plates, having sharp indented edges and a round, hollow space Manila hemp (see under 4). Silicious plates absent; lengthwise the lumen often exhibits remarkable contractions, while the wall is very uneven in thick- ness; at intervals, indeed the lumen is almost entirely inter- rupted; joints and transverse fissures along the fibre; transverse markings and lines, which appear somewhat like zones or knots, are completely lacking, or are very rare and indistinct; com- pletely lignified, hence colored yellow with iodin and sulphuric acid (see 14). Silicious plates absent, also remarkable contractions of the lumen; thickness of the walls very uniform; joints and fissures along the fibre, transverse lines and markings frequent, hence the fibre often appears as if it contains swollen knots; unligni- fied, or only lignified on the external layer of membrane, hence lengthwise the fibre is colored blue with iodin and sulphuric acid or violet or green, or at the most colored yellow in places . . (see 17). 14. Exterior layers of membrane narrow and showing the same coloration with iodin and sulphuric acid as the inner layers, hence the same as the entire cross-section; the lumen hardly ever completely interrupted (see 15). Median layer in sections wide; colored considerably darker with iodin and sulphuric acid; lumen often completely interrupted (see 16). 15. Lumen in general large, diameter as wide or only a little narrower than the wall; in section round or oval, seldom as a point ; no crystals of calcium oxalate True jute. Lumen usually small, diameter much narrower than the thick walHn section frequently as a point; crystals of calcium oxalate of frequent occurrence (detected by ignition). Pseudo-jute (Abelmoschus) (see Fig. 126). 16. Lumen almost always considerably smaller than the wall; ends usually very thick- walled and narrow; calcium oxa- late crystals of frequent occurrence. Pseudo-jute (Urena sinuata). Lumen frequently as wide as or wider than the wall, mostly narrower however; ends broad and blunt Gambo hemp. 376 THE TEXTILE FIBRES. 17. The lumen in the middle portion of the fibre generally line-shaped, much narrower than the wall; ends never blunt, always sharply pointed; sections isolated or in small groups, regular in diameter, sharp-angled and straight-sided polygonals; without separate median layer; iodin and sulphuric acid colors the entire section blue or violet; the lumen in the cross-section is FIG. 126. Abelmoschus Jute. (X325.) (Hohnel.) /, longitudinal view; q, cross- section, e, ends; L, small lumen; v, narrowing of lumen; m, median layer. very small, or as a point, containing a marrow which is colored yellow with iodin and sulphuric acid Linen or Flax. Lumen, at least in the central portion of the fibre, always much thicker than the walls; in section generally more or less flattened, narrow to broad, egg-shaped or oval. Fibre ends blunt, never sharply pointed ; sections almost never sharp-angled polygonals, but more or less oval or elliptical, and with a rounded boundary (see 18). QUALITATIVE ANALYSIS OF THE TEXTILE FIBRES, 377 1 8. Breadth of fibre up to 80 //; maximum length 15 to 60 mm. ; sections always in compact groups, which often consist of many fibres, with thinner or thicker layers of membrane, which are col- ored yellow with iodin and sulphuric acid, hence the fibre is never colored a pure blue, but dirty blue to greenish, and in places yellow; ends often have side branches projecting (see 19). 19. Lignified exterior membranes very thin; lumen in sec- tion narrow, very seldom broad, fissure-like or line-shaped, often branched, without marrow Hemp. Lignified exterior layers often as wide as the interior layers, or wider; the interior layers are often loosened in places from the exterior ones where they are thin; lumen in section scarcely ever narrow or fissure-shaped, but broad, oval, or long ; often contain- ing a yellowish marrow Sunn hemp. CHAPTER XVIII. QUANTITATIVE ANALYSIS OF THE TEXTILE FIBRES. i. Wool and Cotton Fabrics. The finishing materials and coloring-matters should be removed as far as possible by boiling the sample to be examined first in a i per cent, solution of hydro- chloric acid, then in a dilute solution of sodium carbonate (about a one- twentieth per cent, solution), and finally in water. A por- tion of the material is then dried at 100 C. for an hour (or until constant weight is obtained) and weighed; this weight will repre- sent the actual amount of true fibre present in the sample, and the loss will correspond to moisture. Then steep for twelve hours in a mixture of eque 1 parts of sulphuric acid and water, and mix with three volumes of alcohol and water; filter off the dissolved cotton and wash the residue of w r ool well with alcohol. Dry at iooC., and weigh; this will give the amount of wool present.* The following example will illustrate this method: Grams. Sample weighed 3 . 62 After treatment with acid and alkali 3 J 7 Finishing materials, etc o . 45 After drying at 100 C 2.77 Loss as water o . 40 Wool left after treating with acid 1.96 Cotton, by difference 0.81 Hence the composition of this sample would be as follows: Per Cent. Finishing materials 1 2 . 43 Moisture , 1 1 . 05 Wool 54.14 Cotton 22 . 38 * By this treatment the wool suffers a loss of about 2 per cent. 378 QUANTITATIVE ANALYSIS OF THE TEXTILE FIBRES. 379 Another, and perhaps a better, method for determining the relative amounts of wool and cotton in a mixed fabric or yarn, especially when the cotton is present in rather large proportion, is to remove the wool by treatment with a dilute boiling solution of caustic potash. The estimation is carried out in the following manner : The sample to be tested is treated with hydrochloric acid and sodium carbonate solutions as before, in order to remove finish- ing materials, and after thorough washing is dried at 100 C. and weighed. This gives the weight of the dry fibres. The weighed sample is then boiled for twenty minutes in a 5 per cent, solution of caustic potash.* The residue is well washed in fresh water, and redried at 100 C. and weighed. The residue consists of cotton, the wool having been dissolved by the caustic potash. f If the residue becomes disintegrated and cannot be washed and dried as one piece, it should be collected on a tared filter (one which has been dried at iooC. and weighed) and well washed with water, then dried at 100 C. and weighed. The tared weight of the filter subtracted from the latter will give the weight of the cotton particles. Examples: (a) Analysis of a cloth sample: Grams. Weight of sample 5.42 After treatment with acid and alkali 5 . 10 Finishing materials, etc 0-32 After drying at 100 C 4.26 Loss as water o . 84 Cotton left after boiling with caustic alkali 2.82 Wool, by difference i . 44 * It is not advisable to use caustic soda instead of caustic potash, as the results obtained are not as satisfactory. f In case yarns are to be analyzed, the preliminary treatment should consist of a thorough scouring with soap. After drying in the air, the loss in weight should be recorded as grease and miscellaneous dirt. On then drying at 100 C. to constant weight, the loss will represent moisture, and the residue dry fibre. This is then analyzed as in the manner above described. THE TEXTILE FIBRES. Hence the composition of this sample would be: Per Cent. Finishing materials , . . . 5 . 98 Moisture 15 . 50 Cotton 52 . 03 Wool 26 . 49 Since the cotton itself suffers a slight loss on boiling with caustic potash, it is customary, as a correction, to add to the cotton found 5 per cent, of its weight,* and to subtract a corresponding amount from that of the wool. On applying this correction the result of the above analysis would become: Per Cent. Finishing materials 5 . 98 Moisture 15 . 50 Cotton 54-63 Wool. , 23.89 Figured on the weight of the dry fibre, the relative amounts of the two fibres in the above samples would be : Per Cent. Cotton 69-5 Wool 30.5 IOO.O Since, however, in making mixes, the dry weights of the fibres are not taken, we may assume the weight to include the normal amount of moisture held by each fibre. As the normal amount of moisture for cotton is about 8 per cent., and for wool about 1 6 per cent., we may approximate very closely to the true compo- sition of this sample by adding to the dry weights of the fibres their respective amounts of moisture; the relative amounts of cotton and wool then become : Grams. Weight of cotton found 2.82 Add 5 per cent, correction , o. 14 2.96 * The author has found that the cotton will not lose, as a rule, more than 3 per cent. QUANTITATIVE ANALYSIS OF THE TEXTILE FIBRES. 381 This represents 92 per cent, of air-dry cotton. Grams. Hence air-dry cotton would be , 3.22 Weight of wool found i . 44 Subtract correction for cotton . o. 14 1.30 This represents 84 per cent, of air-dry wool. Hence air-dry wool would be i . 54 Therefore the relative amounts of cotton and wool on this basis would be: Per Cent. Cotton 67 . 6 Wool 32.4 (b) Analysis of a yarn: Grams. Weight of sample 5 . 65 Scoured in soap, washed, and air-dried 4-97 Grease, etc o . 68 Dried at 100 C 4.32 Loss as moisture o . 65 Weight of filter-paper dried at 100 C 1.16 Weight of filter and residue of cotton dried at 100 C 3 . 66 Weight of dry cotton 2.50 Add 5 per cent, correction 2 . 62 Correct for moisture at 8 per cent 2 . 85 Weight of dry wool by difference (with correction) i . 70 Correct for moisture at 16 per cent 2 . 02 Hence the composition of this yarn may be expressed as: Per Cent." Grease, etc 12 . oo Moisture 1 1 . 50 Cotton 44- 25 Wool 32 . 25 And the relative proportion of the two fibres would be as follows : 3 82 THE TEXTILE FIBRES. Dry at 100 C. Air-dry. Cotton 60 . 7 58.5 Wool 39.3 41.5 The following scheme for the analysis of a fabric contain- ing wool and cotton is given by Herzfeld : * (a) Estimation oj moisture. Five grams of the fabric are dried at 100 C. until the weight is constant. The loss indicates the amount of moisture present. (b) Estimation oj cotton. Five grams of the fabric are boiled for J hour with 100 cc. of a o.i per cent, solution of caustic soda, then washed with water and treated with lukewarm 10 per cent, caustic potash solution, until the wool fibres are completely dissolved, if necessary the liquid being raised to the boil. The residue is washed with water, then treated for \ hour with dilute hydrochloric acid,f then washed again with water, boiled for J hour with distilled water, washed with alcohol and ether, and finally dried at 100 C. until constant weight is obtained. The residue is cotton. (c) Estimation of wool. Five grams of the cloth are boiled with 100 cc. of a dilute solution of soda- ash for J hour, washed with water, and steeped for 2 hours in sulphuric acid of 58 Be.,t then washed with water, and boiled for J hour with water, and finally washed with alcohol and ether, and dried at 100 C., until constant weight is obtained. The residue is wool. (d) Dressing and dye are found by difference. When a rough, approximate analysis of a wool-cotton is desired, it will be sufficient only to weigh the sample, boil for fifteen minutes in a 5 per cent, solution of caustic potash, wash well in acidulated water, then in fresh water, and dry in the air. On reweighing, the amount of cotton will be ascertained, while * Yarns and Textile Fabrics, p. 145. f The object of washing with dilute hydrochloric acid is to neutralize the excess of caustic alkali in the fibre, so that it may be more readily removed, as caustic alkali remains in the fibre very pertinaciously. % Acid of this strength is somewhat too strong, as it will decompose the wool to a considerable extent. It is not safe to employ sulphuric acid of greater strength than one part of acid to one part of water by volume. QUANTITATIVE ANALYSIS OF THE TEXTILE FIBRES. 383 the loss in weight will represent the amount of wool. Results attained by this process are usually sufficiently accurate to give one a practical idea of the approximate relative amounts of wool and cotton present in a sample of mixed goods. Another method for the separation of wool from cotton in their quantitative estimation is treatment of the mixed fibres with an ammoniacal solution of copper oxide, whereby the cotton is dissolved ; and after washing and drying, the residue of wool is weighed. This method, however, is not very satisfactory, as it is difficult, in the first place, to obtain a complete and thorough solution of the cotton; and in the second place, the wool will be considerably affected by this treatment and more or less decom- posed. Consequently the results obtained by this method are not very accurate, and it cannot be recommended. 2. Wool and Silk. Silk is soluble in strong hydrochloric acid, whereas wool is not soluble in this reagent to any extent. Hence this method may be utilized for the quantitative estima- tion of the two fibres when occurring together. The sample is first treated with acid and alkali in the manner already described in order to remove foreign materials other than actual fibre. It is then dried and weighed; then immersed in cold concentrated hydrochloric acid (about 40 per cent, strength). The silk dissolves almost immediately. The residue is collected, washed thoroughly, dried again, and weighed. The loss in weight repre- sents silk, while the weight of the residue represents wool. Another method, and one which is very satisfactory, is to dissolve the silk by treatment with an ammoniacal solution of nickel oxide, in which reagent the silk is very readily soluble even in the cold. It only requires a treatment of about two minutes to completely dissolve the silk in most silk fabrics other than plush. Richard- son * found that by this treatment cotton lost only 0.45 per cent, in weight and wool only 0.33 per cent. As silk in plush goods and similar fabrics is much more difficult to dissolve, it is recom- mended to boil such material with the nickel solution for ten minutes under a reflux condenser. By this treatment cotton will * Jour. Soc. Chem. Ind., vol. 12, p. 430. 3^4 THE TEXTILE FIBRES. lose only 0.8 per cent, in weight. The nickel solution is best prepared by dissolving 25 gms. of crystallized nickel sulphate in 80 cc. of water; add 36 cc. of a 20 per cent, solution of caustic soda, carefully neutralizing any excess of alkali with dilute sul- phuric acid. The precipitate of nickel hydroxide is then dis- solved in 125 cc. of strong ammonia, and the solution diluted to 250 cc. with water. Instead of the above reagent, a boiling solution of basic zinc chloride may be employed for the purpose of dissolving the silk. This latter solution is obtained by heating together 1000 parts of zinc chloride, 850 parts of water, and 40 parts of zinc oxide until complete solution is effected. Rich- ardson recommends that the sample to be examined should be plunged two or three times into the boiling solution of zinc chloride, care being taken that the total time of immersion does not exceed o ne minute. The zinc chloride solution should be sufficiently basic and concentrated in order to obtain good results. Under the best conditions, cotton loses about 0.5 per cent, in weight, and wool from 1.5 to 2.0 per cent.* 3. Silk and Cotton. The methods given above for separating silk from wool may also be used for the separation and quantita- tive determination of silk in fabrics containing this fibre in con- junction with cotton. Another method for separating silk from cotton is by the use of an alkaline solution of copper and glycerol, which serves as an excellent solvent for the silk. The reagent is prepared as follows : Dissolve 1 6 gms. of copper sulphate in 150 cc. of water, with the addition of 10 gms. of glycerol; then gradually add a solution of caustic soda until the precipitate of copper hydrate which is at first formed just redissolves. This solution readily dissolves silk, but is said not to affect either wool or the vegetable fibres. Richardson, however, has found that cotton heated with this solution for twenty minutes (the time necessary to dissolve silk in plush) lost from i to 1.5 per cent, in weight and became friable * The chief difficulty attached to the use of the zinc chloride solution is that it requires a long and tedious washing to remove all of the zinc salt from the resid- ual fibres. It is best to wash with water acidulated with hydrochloric or acetic acid. QUANTITATIVE ANALYSIS OF THE TEXTILE FIBRES. 385 and dusty on drying; while woolen fabrics lost from 9 to 16 per cent, in weight. Hence the reagent would be useless in the analy- sis of fabrics containing wool. 4. Wool, Cotton, and Silk. Samples of shoddy frequently contain all three of these fibres present in greater or lesser amount, and often it is desirable to know at least the approx- imate amounts of each fibre in the mixture. A method of pro- cedure recommended is the following: A weighed sample of the material is boiled for thirty minutes in a i per cent, solution of hydrochloric acid, washed, and then boiled for thirty minutes in a 0.05 per cent, solution of soda-ash. This preliminary operation is similar to that above described in the preceding analyses, and is for the purpose of freeing the fibres as far as possible from extra- neous foreign matter. After thorough washing and air-drying, the weight of the sample is again taken, and the loss will represent misc-llaneous foreign matter. The sample is then dried at 100 C. to constant weight; the loss in weight will represent moisture. The sample is then divided into two weighed portions; the first is treated for five minutes with a boiling solution of basic zinc chloride prepared as above described, washed thoroughly with acidulated water, then with fresh water, and dried at 100 C. again. The loss in weight will represent the amount of silk present. The second portion of the sample is boiled for ten min- utes in a 5 per cent, solution of caustic potash; washed thor- oughly, dried at 100 C. and weighed. This weight, with a cor- rection of 5 per cent, added to it, will represent the amount of cotton present. The amount of wool is obtained by taking the difference between the total weight of the combined fibres and .the sum of the weights of the silk and cotton. Example: Grams. Sample of loose shoddy weighed 5 . 06 Treated with acid and alkali, and air-dried 4-23 Loss as foreign matter o . 83 Dried at 100 C 3 . 62 Loss as moisture o . 61 386 THE TEXTILE FIBRES. Divided into two portions: Grams. (a) weighed i 95 (b) weighed i . 67 (a) treated with zinc chloride * 1.73 Loss as silk 0.22 (6) treated with caustic potash, residue as cotton o . 34 Loss as wool 1.33 Hence the composition of this sample on the basis of dry fibre would be: Per Cent. Silk II-3 Cotton 21.5 Wool 67 . 2 Von Remont gives the following method for analyzing fabrics containing a mixture of silk, wool, and cotton. Four quantities (A,B,C,D) of 2 gms. each of the air-dried material are weighed out. Portion A is kept aside, and each of the other three is boiled for fifteen minutes in 200 cc. of water containing 3 per cent, of hydrochloric acid. The liquid is decanted, and the boiling repeated with more dilute acid. This treatment removes the size and the major portion of the coloring-matter. Cotton is nearly always decolorized quite rapidly, wool not so readily, and silk but imperfectly, especially with black-dyed fabrics. The samples should be well washed and squeezed in order to remove the acid liquor. Portion B is set aside. Portions C and D are then placed for two minutes in a boiling solution of basic zinc chloride (of 1.72 sp.gr., and prepared as above described), which dissolves any silk present. They are then washed with water containing i per cent, of hydrochloric acid, and again with pure water, until the washings no longer show the presence of zinc. Portion C is squeezed and set aside. Portion D is boiled gently for fifteen minutes with 60 to 80 cc. of caustic soda solution (1.02 sp. gr.) in order to remove any wool. The sample is then care- fully washed with water. The four portions are next dried for an hour at 100 C., and then left exposed to the air for ten hours in order to allow them to absorb the normal amount of hygro- QUANTITATIVE ANALYSIS OF THE TEXTILE FIBRES. 387 scopic moisture. The four samples are then weighed, and call- ing a, b y c, and d their respective weights, we shall have a b=dye and finishing material; b c = silk; c d= wool ; d= cotton (or vegetable fibre). This method is open to objections, as the plan of using air- dried material, then drying at iooC., and subsequently expos- ing to the air again before reweighing, is liable to give very errone- ous results. Richardson recommends that the samples should be thoroughly dried at 100 C. before being weighed out, and the treated portions should subsequently be dried at the same temperature before weighing. In order to prevent the sample from absorbing moisture during weighing, it is best to use a weighing -botte for holding the dried fibre. The sample before drying is placed in a weighing-bottle (the weight of which has been ascertained previously) and heated in an air-oven at 100 C. for the time specified, during which the cover of the weighing- bottle is removed. After the drying process is completed the stopper is replaced in the weighing-bottle; the latter is taken from the oven, allowed to cool, and is then weighed. The dif- ference between this weight and the weight of the empty bottle will give the amount of dry fibre. Treatment with a boiling solution of 3 per cent, hydrochloric acid for the purpose of removing finishing materials is rather too severe, as the acid will act on the wool and the cotton, some- times causing considerable error. Boiling with a i per cent, solution of acid for ten minutes is to be preferred. The following is given as a practical method to determine if shoddy contains, cotton and silk fibres: Boil 10 gms. of the shoddy to be tes ed for one hour in 400 cc. of water containing 0.8 gm. of alum, 0.3 gm. of tartar, i cc. of hydrochloric acid, o.i gm. of chrome, and 0.05 gm. of bluestone. Rinse and dye with 0.3 gm. of logwood extract. Rinse and dry. The undyed fibres are then picked out and examined; cotton will remain white, while silk will be colored a dingy red. 3 88 THE TEXTILE FIBRES. The analysis of heavy pile fabrics containing a mixture of fibres is especially difficult unless the fabric is disintegrated. In the analysis of plush for the amount of silk present, Richardson suggests treating the sample with a boiling solution of basic zinc chloride in the manner previously described; but when silk is to be determined in light fabrics (especially in the presence of wool), it is best to treat the sample for one to three minutes with a cold solution of ammoniacal nickel oxide. He gives the following comparison of results in the analysis of a sample of plush, using the three different methods for dissolving the silk: By Solution of Ammoniacal Nickel Oxide. By Solution of Basic Zinc Chloride. By Copper- glycerol Reagent. ^Moisture and finish II - 34 II .OO IO O4 Silk 4? . 60 4 3 22 326 Cordia latifolia 133 Cordonnet silk 112 INDEX. 449 PAGE Cork tissue 151 Cortical layer of wool 24 cells in 24 Corypha umbraculifera 134 Cosmos fibre 71 Cotted fleeces 38 Cotton, absorbent, quality of 208 absorption of acids by 230 absorption of alkalies by 230 acetylation of 231 action of acid dyes on 231 action of acid salts on 231 action of ammoniacal copper oxide on 199 action of basic dyes on 231 action of basic salts on 231 action of coloring-matters on 231 action of dilute sulphuric acid on 224 action of enzymes on 232 action of high temperatures on 222 action of hydrochloric acid on 224 action of hydrofluoric acid on 227 action of metallic salts on 231 action of mineral acids on 223 action of natural dyes on 231 action of nitric acid on 224 action of organic acids on 227 action of oxidizing agents on 231 action of saliva on 232 action of Schweitzer's reagent on 222 action of strong sulphuric acid on 223 action of substantive dyes on 231 action of zinc chloride on 223 active chemical groups in ' 231 albuminous matter in 212 "botany of 1 60 chemical constitution of 209 chemical reactions of . . 222 coloring-matter in 210 diameter of different varieties of t 187 dry distillation of 222 effect of bleaching on strength of 233 effect of mercerization on strength of 238 estimation of, in fabrics 378,379, 382 fermentation of 232 first cultivation of, in America 160 grading of, as to value 179 historical data concerning 157 450 INDEX. PAGE Cotton, hygroscopic quality of 206 influence of chemical properties of, in dyeing 231 influence of moisture on strength of 208 introduction of, into China 158 introduction of, into Europe 157 introduction of, into Japan 158 length of different varieties of 187 mention of, by Herodotus 157 microscopic classification of 202 microscopical properties of 201 mineral matter in 209, 211 names given to, in various countries 172 natural impurities in 209 Origin and growth of 1 60 pectin compounds in 211 phosphoric acid in 211 physical changes in, by mercerizing 236 physical properties of 203 physical structure of 186 regain in conditioning 207 thermochemical reactions of 230 time for sowing 163 use of, by early American races 159 use of, in Egypt 159 use of, in India : 157 use of, in Peru 1 60 Cotton and linen, distinction between 342 Cotton fabrics, analysis of 408 Cotton fibre 365, 373 analysis of 213 conditions influencing quality of 171 development of 169 elasticity of 204 microchemical reactions of 202 microscopy of 360 physiological development of 168 structural parts of 198 tensile strength of 204^ twist in 200 Cotton grass 144, 357 Cotton plant 161 analysis of 166 best soil for cultivation of 172 best temperature for growth 171 chemical constituents of 168 cross-fertilization of 178 cultivation of. . .162 INDEX. 451 PAGE Cotton plant, fertilizing constituents in 167 influence of weather on growth of 172 list of species of 173 time required for maturity of 165 varieties of 173 Cotton-tree 249 Cotton-wax 209 Cotton yarns, tensile strength of 205 Cottonized ramie 145, 293 Cottonseed, constituents of 168 Count of cotton yarns, method of ascertaining 180 Courtrai flax, grades of <. 272 Cow-hair 85 microscopy of. . J 85 Cox Royal Arch Silk cotton.. 420 Crawford Premium cotton 420 Peerless cotton 420 Craping of silk fabrics 125 Cretan hemp 297 sheep 10 Crimean sheep 10 Crin vegetale 136, 144 Crossland cotton 420 Crotolaria juncea 133, 297, 306 retusa , 308 sericea 308 striata 308 tenuifolia 253, 298 Cryptostemma calendulaceum 356 hairs 358 Cuba bast 138 Cuban hemp 298, 306 Cuprammonium silk 262 solution, preparation of 263, 341 reaction of fibres with 340 Cupric sulphate, reaction of fibres with 336 Curumbar sheep 10 Cutose 151,221 CycadcB macrozamia 355 Cyprian gold thread 7 Cystisus scoparius 343 D Dacca cotton 173 Dalkeith Eureka cotton 420 Datisca cannabina '. 297 "Dead" cotton 186 45 2 INDEX. PAGE Dean cotton 420 Bearing cotton 420 Deccan sheep 10 Degumming of silk 1 1 6 Denier 112 international 113 Deniers, conversion tables for 114,115 varieties of 112 Deo cotton 174 Deora jute 286 Desi jute 286 Deswal jute 286 Dharwar cotton 183, 190 Dhollerah cotton 183, 191 Diamond cotton 420 Diazotized wool 45 acid number of 45 action of phenols on 45 iodin number of 45 Dickson Cluster cotton 420 cotton 420 Improved cotton 420 Dicotyledonous fibres 368 plants 134 Discharging silk 1 1 6 Dixon cotton 420 Doe-hair 17 Domestic sheep i o Double silk cocoons 98 Drake Cluster cotton 420 Drought-proof cotton 420 Drying of wool 53 Duklum sheep i o Duncan cotton 420 Mammoth cotton 420 Dutch flax, grades of 272 Du Vivier's silk 260 Dyeing, influence of chemical groups in wool in 49 structure of wool fibre with reference to 28 E Early Carolina cotton 421 East cotton 421 Improved Georgia cotton 421 Echappe silk 112 Economic classification of fibres 137 INDEX. 453 PAGE Edgeworthia papyrifera 142 Edisto Sea Island cotton ^9 Edredon vegetate 251 Egyptian cotton 175 Bamia variety of 181 use of, for mercerizing 243 Elairerin 39 Elais guineensis 134 Elasticity of wool fibre 25 Elephant grass '. 144 Ellsworth cotton 421 Embroidery silk 112 Enzymes, action of, on cotton 232 Epidermal scales, absence of, in wool 16 arrangement of, on wool 21 number of, on wool fibres 22 Eria silk 102 Eriodendron anfractuosum 251, 362 Ejriophorum angustifolium 357 latifolium 356 Esparto 134, 368 grass 133 Estimation of cotton in fabrics 378, 379, 382 moisture in fabrics. . . 382 wool in fabrics 3?8, 382 Ethridge cotton 421 Eupatorium cannabinum 298 Eureka cotton 421 "Excelsior" 136 Excelsior cotton 421 Exogens 134 Extra Early Carolina cotton 421 Extract wool 70, 71 F Fabric fibres 137 Fagara silk 102 False hemp 298 sisal hemp 298, 319 Farrar Forked Leaf cotton 421 Prolific cotton 421 Feather grass 134 substitutes 140 Fehling's reagent, preparation of 394 Felting, cause of, in wool 19 Fermentation of, in cotton * 232 454 INDEX. " PAGE Ferric sulphate, reaction of fibres with 336 solution, preparation of 337 Fezzan sheep i o Fibre-cells, method of isolating 341 Fibre sections, method of preparing 341 Fibre-testing machine 415 Fibroin 116 action of polarized light on 123 amount of, in raw silk 118 chemical composition of 1 1 8 chemical reactions of 120 comparison of, with keratin 119 composition of 120 decomposition products of 119 preparation of pure 118 presence of amido group in 119 Fibro- vascular fibres 134 Fiji sea-island cotton 181, 189 Fimble hemp 298 Finishing materials, estimation of, in fabrics 382, 407 Flacherie 100 Flax, commercial grades of 271 countries cultivating 271 cultivation of, in America 271 dimension of fibre elements in 278 methods of retting 273 Flax cellulose, isolation of pure ' 278 fibre, bast cells of 280 properties of the wax on 281 strength of 279 Flax-like fibres 141 Flax plant, cultivation of, for seed 272 description of 272 species of 271 Flax-retting, chemistry of 276 Fleece, amount of fibre in . 33 Flemish flax 272 Florette silk 112 Florida bowstring hemp o 330 sea-island cotton 181,189 Floss silk 98, 1 1 1 French flax, grades of 272 Friesland flax, grades of 272 Frisonnets silk 98 Prisons silk 98 Fruit fibres 131, 142 Fuchsin reaction of fibres with , . . , 336 INDEX. 455 Fuchsin solution, preparation of 336 Fur 9 spinning of 9 Purer 3 50 Dana's System of Mineralogy Large 8vo, half leather, 12 50 First Appendix to Dana's New "System of Mineralogy." 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