While it remains in the state of a caterpillar, the Silk-worm changes its coat four times, and previous to each moult refuses its food, and appears in a very sickly condition. As soon as its nest or cocoon is finished, and it has changed into the pupa-state, the cocoons are carefully removed from the place where the animal had formed them; and after those which it is intended to keep, that they may perfect their changes and lay eggs for the ensuing year, are removed, the remainder are placed in large vessels, each covered with a thick blanket; they are then exposed to heat sufficiently powerful to destroy the life of the pupæ. This is generally accomplished by placing the vessels in an oven, heated to about the same degree as that of a baker after his loaves are drawn; here they are suffered to remain for about an hour, they are then withdrawn, but the blanket that covers them, is not removed for the space of five or six hours.
The first process in preparing the silk, is winding it off the cocoons: for this purpose, after the rough outsides are removed, several handfuls at a time are thrown into a vessel containing water, and placed over a gentle fire, the water is then allowed to be heated to nearly the boiling point; a short stunted brush formed of heath or any other shrub of that description, is now gently moved about among the cocoons, and on withdrawing it from the water, the ends of the silk are found to have adhered to it in several places; the winder then gathers together with her fingers, as many ends as she intends the first description of thread to consist of, and hands them to an assistant, whose office it is to turn the reel as soon as the silk is laid upon it; the principal workwoman, in the mean time, continually adds to the thread the ends of fresh cocoons, as soon as the first are exhausted.
The silk, when reeled off in this manner, is called singles, and is used in weaving to form the weft, that is, the thread that crosses the cloth from side to side. Another description of silk threads, are called trams, and these consist of two or three singles twisted together; but the strongest and most valuable sort is the organzine, which is formed by placing skeins of singles upon a reel, and as they are wound off, they are, by the assistance of machinery, strongly twisted. Two or three of these are then taken, and the whole again twisted together to form a stronger thread; this thread is the organzine, and is used for the warp or length of the cloth.
The process of making organzine, is called throwing, and the throwsters form a very important branch of the silk business. Before the year 1719, the whole of the thrown silk used in England came from abroad, but at that time Sir Thomas Lombe and his brother erected a large mill at Derby for the purpose of forming organzine, and obtained an exclusive patent for its manufacture, for the term of fourteen years; at the expiration of that term, they applied for a renewal of their patent, but it was refused by Parliament, and the trade has since then been open to competition. Some idea may be formed of the extent to which the silk manufacture is carried on at present in England, by the fact that no less a quantity than four million, six hundred and ninety three thousand, five hundred and seventeen pounds of raw silk were imported for home consumption, in the year ending January 1831.
The substance on which this valuable caterpillar feeds, is the leaf of the Mulberry Tree; and Providence as if to ensure the continuance of this useful species, has so ordained it, that no other insect will partake of the same food; thus ensuring a certain supply for the little spinster.
The engravings which illustrate this article are copied from original Chinese drawings: the first shows the apartment in which the worms are fed, and the manner in which the little trays containing them are arranged. In the second, the cocoons being completed by the insect, are being cleared of dirt and dead leaves, before they are removed from the frames on which they had spun. The third represents the winding off the silk into singles, but the windster appears for the moment to have left her post for the purpose of blowing the fire. In the fourth engraving, a Chinese silk-loom, is shown; the figure seated above, among the machinery, appears to assist the labour by means of her weight.
WINDING THE SILK FROM THE COCOONS.
