SILK, the web or envelopement of the caterpillar, of a species of moth called the Phalena mori ; which, being converti ble to various purposes of utility and elegance, forms an important article in commerce, as the.material of a valuable manufacture. The caterpillar, or silk worm, when full grown, encloses itself in a loose web, in the midst of which it forms a much closer case or covering, of an oval form, and varying in colour from white to a deep orange, but usually of a bright yellow colour. In this case, or ball, the animal becomes a chrysalis, and remains enclosed about fifteen days ; when, having resumed active life, in the form of a moth, it makes a hole at one end of its prison and comes out. This, as it destroys the silk ball, is prevented, in those countries where silk is cultivat ed, by killing the chrysalis by means of heat. See PlIALENA.
The silk-worm is supposed to be a na tive of China, at least the Chinese were the first nation in the world acquaipted• with the manufacture of silk. It was lit tle known in Europe before the time of Augustus. Galen, who lived about the year 160, mentions silk as in use no where but at Rome, and only among the rich. The Emperor Heliogabalus, who died in the year 220, is said to have been the first man that wore a holosericum, or dress made wholly of silk ; princes, as well as subjects of the greatest quality, wearing only a stuff made of silk mixed with other materials. In the time of Aurelian, silk was sold in Rome for its weight in gold, and long continued to bear a great value, from the expense attending the mode in which it was pro cured. The only silk then known was that of China, which was brought from thence, in the raw state, to Berytus and Tyre, in Phiznicia, where it was maim factored ; but this branch of commerce being interrupted by the conquests of the Scythians, the Emperor Justinian be came desirous of establishing the culture of silk within his dominions ; for which purpose he employed two monks, who had been in India, to procure the eggs of the insect from China. This was accom plished about the year 555; the eggs were hatched at Constantinople, and the breed of the insect being carefully en couraged, raw silk was soon produced in abundance, which was worked up into manufactures at Athens, Thebes, Corinth, and other places. It appears, however, that for many years after the establish ment of the culture of silk in Greece, garments of this material continued to be very highly valued ; as, about the year 790, Charlemagne sent two silken vests as a present to Offa, king of Itilercia. About the year 1130, the silk manufac ture had made such progress in the island of Sicily as to excite the jealousy of the Venetians, from its interfering with their importations of silks from Greece.—From
Venice and Sicily the silk manufacture spread through Italy, from whence it was introduced into the southern provinces of France.
As soon as the worms have produced their balls, or cocoons, they become an article of trade, for in those countries where silk is cultivated few persons reel off their cocoons, but sell them to others, who make this operation a separate busi ness. The silk, as formed by the worm, is so very fine, that if each ball, or cocoon was reeled separately, it would be totally unfit for the purposes of the manufacturer ; in the reeling, therefore, the ends of several cocoons are joined and reeled together out of warm water, which,softening their natural gum, makes them stick together, so as to form one strong smooth thread. As coften as the thread of any single cocoon breaks, or comes to an end, its place is supplied by a new one, so that, by continually keep ing up the same number, the united thread may be wound to any length: the single threads of the newly added co coons, are not joined by any tie, but simply laid on the main thread, to which they adhere by their gum ; and their ends are so fine as not to occasion the least perceptible unevenness in the place where they are laid on. The apparatus for reeling consists merely of a small open kettle of water, under which is a fire to keep it hot, and a reel of a very simple construction. Care should be taken in the operation, that the silk when reeled off may consist of a smooth thread, of equal thickness and strength, not flat, but of a round form, having the small threads of which it is composed as equal. ly stretched and firmly united as possi ble ; and that the several rounds, as they lie on the reel, should not be glued to gether. When the skein is quite dry, it is taken off the reel, and a tie is made with some of the refuse silk on that part of the skein where it bore upon the bars of the reel, and another tie on the op posite part of the skein ; after which it is doubled into a hank, and usually tied round near each extremity, when it is laid by for use, or sale. In this state, in which all the silk that is brought from India, and a considerable part of what comes from Italy and other parts, arrives, it is called raw silk ; the principal part of it is afterwards sent to a mill to be thrown ; that is, to have two ends of it doubled and twisted together, by which it is converted into tram, or organzine, according to the fineness of the silk, and the purposes to which it is intended to be applied in the manufacture. See