This section is from the "A Complete Dictionary of Dry Goods" book, by George S. Cole. Also available from Amazon: A complete dictionary of dry goods and history of silk, cotton, linen, wool and other fibrous substances,: Including a full explanation of the modern processes ... together with various useful tables.
Spun Silk. - Fabrics made of silk are of two kinds, according as they are made of reeled or spun silk. In working the latter there is no attempt made to use the continuous thread as spun by the silk worm within the cocoon, but the cocoon is treated as a bundle of fibers, and spun like wool or cotton). The cocoons for this purpose are imported in bales, largely from Lyons, the centre of the European silk commerce, and from China and India. The cocoons on arrival are picked over, freed from adhering dirt, and assorted with regard to color. They are then ready for the first process in the spun-silk industry - the freeing of the silk fiber from the gum with which the silk worm has glued it together to make its cocoon, and the loosening of the fiber itself. This is done by boiling in soap-water. They are then rinsed in clear water, dried by steam, and exposed to free air in great drying-rooms. They emerge no longer cocoons, but puffy little balls ready to be beaten out into sheets of fiber something like cotton batting. These sheets of silken batting, formed not only of pierced and inferior cocoons, but also of the "waste" from throwing processes and all other stages through which the reeled silk has passed, are next food for combing or carding machines. There are several patterns or varieties of these machines, all serving the same purpose of combing and cleaning the fiber, much as one combs out his hair. In the first combing the largest and strongest fibers, called the first "draft," left on the cards are used for the finest goods; the waste left on the cards becomes food for the next combing machine. The poorer fiber goes through 4 or 5 machines, until the possibilities of the material is exhausted. The last fiber that can be used is roughly spun into the irregular noil yarn, which is the material composing the lustreless "raw silk" goods, so called, of the upholsterer, a fabric which frequently defies an expert to determine whether of cotton or silk. The spun silk, after passing through 16 or 18 machines from its original shape in the cocoon, is now in a yarn, or thread, corresponding to the "reeled" silk as it is ready for the weaver. The finished yarn is often very lumpy and requires severe improving. A curious process sometimes used is the "gassing" or singeing, in which the yarn is run continuously through a gas flame at a speed carefully regulated so that the flame shall burn off the loose filaments and clean up the fiber without burning the body of the thread itself. If the thread slackens, a clever device called a guide-wire instantly turns off the flames. The last machine, the "reeler," delivers the thread upon a reel, which permits the making of skeins, in which shape all the dyeing, except for piece-dyed or printed silks, is done. Printed silk is made in much the same fashion as calico. When the figure is white upon a dark ground the silk is bleached, then run between rollers that print the ground, leaving the figure blank. Colored figures on white or light grounds simply reverse the process. Complex patterns, employing many colors, have a separate roller and printing for each tint.
Dyeing, Adulterating and Tests for Silk. - Next to wool, silk is the easiest fiber to dye. In fact it runs riot in the whole gamut of color. The aniline dyes evolved by German chemists from coal tar give many of the most delightful tints. For the rest there is madder and Brazil wood, tumeric, and cochineal, saffron, indigo, logwood, fustic, Prussian blue, and many more. There is no shade, no tint, no cloud of color applied to any known fiber but may be caught and repeated upon silk. Dyeing is always a hand process, as the color of a dyer's hand suggests, and here machinery does not attempt to interfere. Long wooden troughs fill the sloppy and steamy room, into which the great skeins of silk yarn are dipped by parti-colored human beings, who move them to and fro to make sure all parts of the skein are touched by the dyeing fluid. There is good dyeing and bad dyeing, honest dyeing and false dyeing, and a silk maker inspired with intent to deceive can make his yarn take 300 per cent of extra weight by the use of heavy chemicals in the dye-trough. Silk, we have seen, loses about one-fourth of its weight in scouring. To make up for this loss, it has long been the practice to dye dark-colored silks "in the gum," the dye combining in these cases with the gum or gelatinous coating. Such silks are known as souples. Both in the gum and in the scoured state, silk has the peculiar property of absorbing heavy dye-matters, though remaining to outward appearances undiminished in strength and lustre, but much added to in weight and thickness. Silk in the gum, it is found, absorbs these heavy dyes more freely than the scoured; so to use it for weighting there are these great inducements - a saving of the costly and tedious scouring; a saving of the 25 per cent weight which would have been lost; and a surface on which much greater deception can be practiced. In dyeing silk black, a certain amount of weight must be added; and the common practice in former times was to make up on the silk the 25 per cent that was lost in scouring. Up to 1857, the utmost the dyer could add was "weight for weight," but an accidental discovery in that year put dyers in the way of using tin salts and nitrate of iron in "weighting," with the result that they can now add 40 ounces per pound to scoured silk, 120 ounces per pound to souples, and 150 ounces per pound to spun silks, and yet these compounds are called silk. The use of different chemicals enables dyers to weight all colors the same as black. The apparent lustre of the fabrics is preserved because the silk fiber absorbs the heavy chemicals to a degree truly wonderful, and there is a semblance of silk with a good "body" that attracts customers. Very brief wear reveals the deception. It will crack and grow rusty in a night. The cohesiveness, the elasticity, and the real strength of the fiber are greatly reduced. As a further evidence the goods have become highly combustible, and, when burned with a match, fail to give the usual odor of animal matter by which good silk is so readily recognized. This manner of dyeing accounts for some of the cheapness as well as the bad wear of certain foreign fabrics which look as well at first sight as goods at a much higher price. Some of the foreign black dress silks are so highly "loaded" with nitrate of iron as to give color to the belief in "spontaneous combustion" of silk, which caused the steamship companies in 1879 to refuse to freight the heavier foreign silks. The carbon of the silk and the nitrate make a compound closely parallel to gunpowder, which is simply cotton fabric soaked with nitric acid. The silk mills of the United States manufacture the finest and most honest fabrics in the world, and challenge consumers to test the purity of their silks, which can be done by raveling out the threads. If heavily loaded, they will be sure to break easily, feel rough to the touch because of the particles of dye, taste inky to the tongue, and burn smoulderingly into a yellow, greasy ash, instead of crisply into almost nothing.
After dyeing, the huge skeins are washed and dried, and are now ready for the process of weaving. Like all fabrics, woven silk is composed of a series of continuous threads lengthwise in the piece, called the warp, and of cross-threads woven in and out of the warp according to the pattern of cloth, called the weft, or filling. As previously stated, warp yarn is first spun, then doubled, then close-twisted, and is called "organzine;" weft yarn is first doubled, then spun, is but slightly twisted, and is called "tram." The first process of the weaving must be to get the warp, and the weaver gives word that he wants a warp 250 yards long, and of 3,000 to 6,000 "ends" or threads, which last number would make a very wide piece of goods. The original bolts of silk as they come off the loom are usually about 200 to 225 yards in length. In a good gros grain dress silk there are about 4,800 warp threads lying side by side in the width of the fabric, being 240 to the inch. (In the best standard calico there are 64 to the inch.) The Jacquard loom, with its marvelous power of producing infinite detail of figure, is the machine upon which all American silks are woven. It will be found described under the head of Jacquard. The invention of this simple improvement in the year 1800 won for Jacquard a bronze medal, the notice of Napoleon, and a pension of 1,000 crowns. Besides the varieties of pattern made by the arrangements of the harness-frames, which includes the difference between silk and satin, there are other means of varying goods. In satin the warp is thrown mostly to the upper surface, and as the silk warp is the most lustrous, the satiny effect is produced. Grenadine is produced by threading the warp only into alternate eyelets in the reed and harness, and by feeding the weft slowly, so that a mesh is formed. Stripes, if in the length are made by warp threads of different colors; if in the width, by feeding the weft from shuttles carrying different colors of thread, each of which, by an automatic device, is lifted into position to be thrown at the proper moment. Gros grain is made by plain weaving, the woof being of a thickness to correspond with the rib or grain. Bedford cords, Ottomans, and Faille are made in the same manner - a heavy thread of weft making the rib across the goods. Foulard is simply the general name for plain-woven silks not dyed in the yarn. After silk cloth is woven it is taken from the loom for finishing. This a is considerable business in itself. Two of the preliminary processes are gassing and burling. Gassing is a repetition of the process used for the yarn, viz., the passing quickly in contact with a light flame, which burns off any stray filaments without injury to the fabric. In burling, the fabric is unwound from one roller and wound at a short distance away upon another, the quick eye of a woman being on the alert to catch any knots or "burls" in the silk, which she removes with a pair of tweezers. The fabric is then calendered or "glossed" by being run between copper rollers, after which it is folded in 1 1/4 yard lengths and is ready for the packer. In some kinds of finishing the silk is subjected to a steam spray of gum and shellac, which improves its luster; and foreign silk is sometimes refinished in this way by American finishers. If, however, the material is not yarn-dyed, it must go from the loom to the dye shop, or to the printing-press. Silk, like calico, is printed on a stout upright press, having a roller for each color that is to be used. On this roller, which is of copper, is cut the portion of the pattern to be printed in this color, and when the silk carried around a great cylinder in the center, has been pressed in turn against each of these rollers, the pattern is complete. In either case it must be washed, dried and calendered before it is ready to sell.
Velvet is made in two ways, that of the finest grade being woven by looping the warp threads over fine wires, which give by their size any desired length of pile. When the weaver has made a few inches of web, requiring several hundred of these wires he stops the loom and with deft hand runs a keen knife along each of these wires, guided by a fine groove in its upper surface. The other system is that made possible by the power loom for the production of pile fabrics. In this two cloths are really woven together the pile binding the two, until a blade working like a knife or sickle cuts them apart. Velvets must be carefully looked over to obviate imperfections, and are then ironed, brushed, and if necessary, sheared to the finest possible degree of evenness. Watered silks and moire antiques are now made by the pressure of hot rollers upon the parts showing the "water lines" - a method which has superseded the old hand process of scraping down or hammering in the lines. Brocades are simply figured goods, the figure being produced by throwing the warp or the weft thread to the top in the Jacquard weaving. The cost of putting a brocade figure to a plain background varies greatly with the material used for the brocade, the number of colors used in the figure, and the elaboration of the pattern. The simplest brocaded figure can be added to a piece of silk at a cost of about 15 cents a yard; and it may add ten times that sum to the cost of a yard if it be an elaborate all-over design.
Half-silk Goods. - By this term is meant fabrics which are made partly of silk and partly of cotton; sometimes the warp is of cotton and the weft of silk, or the reverse may be the case. It is obvious that these fabrics cannot have the same luster as whole silk fabrics, and the aim of finishers is to make them appear as lustrous as if made entirely of silk. After weaving, these goods are generally boiled off, and if required are then dyed and dried. In the condition this leaves them, the fibers of which they are composed are distinctly visible, the silk being lustrous, the cotton dull and heavy. The object of the finisher is to give the whole a similar appearance by imparting a gloss to the cotton, and in this silk-finishers have been successful, for they make half-silk goods look as if they were composed entirely of silk. Two kinds of finish are distinguished in the trade: one, known as "atlas," is finished or is bright on one side only; the other, called the "ottoman" finish, is bright on both sides. To obtain either of these results a finishing agent is first applied to the goods, and they are then dried and as a general thing calendered. The materials used for the finishing are gum tragacanth and glue, of the purest and palest quality. For the "atlas" finish the fabric is wound on a roller as free from creases and wrinkles as possible, and the face of the goods filled with the composition of glue and gum. This is applied by means of a roller. The fabric is then dried, and afterwards calendered just enough to give them the required gloss. It will now be stiff; especially if a large proportion of glue - has been used on them. In order to soften them they are steamed by passing through a fan-steaming arrangement, which does not destroy the gloss, while it gives the fabric a softer and more pliable feel. For the "ottoman" finish the goods are treated on both sides as in the case of the atlas finish. The stiffness of the finished goods will depend upon the relative proportions of glue and gum tragacanth in the stiffening mixture, glue giving a hard feel and gum a softer. Zinc sulphate is always added to prevent the growth of mildew in the finished goods on keeping. The luster so produced will remain until fabric is washed. A large proportion of medium-priced silks are filled with cotton or with jute, more especially the cheap corded goods.
Some all-silk fabrics sell for $1 a yard, others sell for $5, on account of two things - the quality of the silk thread, and the amount of it. The raw silk, as it comes from the cocoons, is of very different kinds. Some of it is long and even and smooth, while inferior qualities are rough and brittle, and in short lengths. The poor qualities do not stand wear as well as the best ones do, and, not being worth so much money, are utilized for the cheaper grades of silk fabrics. The long, glossy threads go into the best silks, and because in these beauty is sought before cheapness; a greater amount of silk is put into a yard—that is, the silk is heavier.
Although there is an abundance of durable, inexpensive silk in the markets of the United States, there is also, at the same time, plenty of shining cloth which, when purchased, turns out a reproach and a shame upon ordinary judgment in the investment of money. As a general rule, it may said that the softest silks are the best silks - that is, silks possessing a softness combined with weight, which feel as if they had no stiffening in them. By twisting a piece of silk around the finger a buyer can tell something about it. If it smoothes out without creases, it will wear well. By touching a match to a thread, it can be ascertained if there is cotton in it. If it is all silk, it will burn with difficulty; if there is cotton in it, it will light readily. Good silk is strong, and when it breaks it will fly into many little ends. Pure silk does not stiffen when wetted and dried ; and, if black, the dye should have a slight tinge of green when the light is seen through it. Stiff silks do not wear well, as they cannot be pure. The inexperienced buyer of silk should be wary of the bargain that can " stand alone." The lower the price of a heavy silk the more likely it is to be of shimmered cotton, or to be weighted with dyestuffs ; hence the only wonder is that it will bend at all. If silk be crushed together in the hand, and suddenly released, it should spring out quickly, leaving but little crease. This spring is caled the verve, of which poor silks have little or none; those adulterated with jute are also deficient in this characteristic. Buyers should look to it that the silk is not piece-dyed. However good the quality, the garment, upon very brief wear, soon collapses into matted limpness. The "dipped" silk may be easily detected by a brackish stiffness, and by a "flat-iron shine," that a careless inspector mistakes for a gloss. Cheap China and Japanese silks are filled with jute. Silk of any description can be identified in a mixture with any other fiber, animal or vegetable, by means of concentrated hydrochloric acid, which dissolves it immediately and completely, without appreciably affecting any woolen or vegetable fiber with which the silk may have been interwoven. Silk is also dissolved by cold nitric acid, which does not affect wool. A common test is to rub one corner of a piece of silk, as though washing it. After this operation, if the silk be good, it will, on being brushed out, look as smooth as ever; and if, on holding it up to the light and looking through it, no trace of the rubbing is discernible, be sure the silk is good. [See Linen, Fibers]
Pure silk is practically indestructible, though wearers of silk dresses may not think so. The reason, however, is that even in garments made up of pure silk, the dyeing affects its wearing qualities. A prominent silk manufacturer is authority for the statement that if one would get a heavy, undyed silk dress, it would last forever. To prove this theory, a story is told to the effect that some years ago a silk mill was robbed of a large quantity of raw silk. The thieves set fire to the mill, in order to conceal their work, but the fire was extinguished in time to reveal the robbery of several barrels of silk that had just been skeined. Search was made for the missing silk, but it was not found until eight years afterward, when, by accident, it was discovered buried some distance from the old mill. The barrels and the hoops had been completely rotted by this long burial, but the silk remained in such perfect condition that it was made into sewing silk. The silk remained smooth, even and strong, showing that even this harsh treatment had not injured its qualities. Pure silk of any description is an agreeable and healthy material. Used in dress, it retains the electricity of the body; in the drapery of rooms and furniture-covers it reflects the sunbeams, giving them a quicker brilliancy, and it heightens colors with a charming light. It possesses an element of cheerfulness, of which the dull surface of wool and linen are destitute. It also promotes cleanliness, will not readily gather dirt, and does not harbor vermin as kindly as wool does. Its continually growing use, accordingly, is beneficial in many ways. Grace and beauty, even, owe something to silk. The more silk ribbons, the more silk kerchiefs and robes are used - instead of linen and wool - the more graceful becomes the outward aspect of mankind. The fluttering of ribbon, the rustling and flowing skirts of silk, the kerchief knotted loosely around the neck, have materially contributed to make the prevailing customs more natural and pleasing to the eye.