machinery can be, and often is, employed from three to six hours after the hands have left work. When water-power is used, the portion of the silk-machinery which contains the swifts, generally works all night without being tended.

NATURE AND OPERATIONS OF A SILK FACTORY.

The silk worm was first rendered serviceable to man in China, about 2700 years before the Christian era. From that country the art of rearing it passed into India and Persia. It was only at the beginning of the sixteenth century that two monks brought some eggs of the silk worm to Constantinople, and promulgated some information on the growth of the caterpillars. This knowledge became, under the emperor Justinian, productive of a new source of wealth to the European nations. In 1564, Traucat, a common gardener of Nismes, laid the first foundation of a nursery of white mulberry trees, with such success as to enable them to be propagated within a few years over all the southern provinces of France.

This insect is first an egg, which the warmth of spring brings forth and this, as it enlarges, progressively casts its skin three or four times, according to the variety of the insect. This caterpillar at the end of twenty-five or thirty days having attained maturity of size, ceases to eat for the remainder of its life, merely discharges its excrementitious matter by spinning a cocoon, within which it is changed into a chrysalis. In fifteen or twenty days they come out, a couple of butterflies, male and female.

The eggs of the silk worm are covered with a liquid, which glues them to the piece of paper on which the female lays them; and they may be freed from it by dipping them in cold water, and afterwards drying them. They should be preserved at the temperature of from 54° to 59° Farenheit. When the heats of April begin to be felt, they must not be suffered to act on the eggs, because they would bring on incubation before the first shoots of the mulberry have come forth to supply food to the young worms. This period should be kept back also, becanse it is proper to hatchi almost all the eggs together, or at least in successive broods corresponding to the extent of the breeding establishment. The eggs may be laid in a stove room, and exposed to a warmth gradually increasing, till it reaches the temperature of 86° Fahrenheit, at which it must be kept stationary. Nature finishes the work of incubation in eight or ten days. The teeming seed is now covered with a sheet of paper pierced with holes, about one twelfth of an

inch in diameter, through which the young worms creep upwards instinctively to get at the mulberry leaves previously placed above. Whenever the leaves become loaded with worms, they are transferred to plates of wicker work covered with grey paper. This transfer is repeated twice every day.

In the course of from forty-eight to seventy-two hours the whole of the eggs should be hatched. The nursery for breeding the worms ought to be a well aired apartment, free from damp, cold, and excess of heat, from rats and other destructive vermin. For breeding twenty-one ounces avoirdupois of seed, the chamber should be thirty-three feet wide by eighty feet long, and be provided with fire-places for heating and ventilating it; the window casements should be glazed. The temperature must not be allowed to fall under 66° Fahrenheit; it may be raised to 92° Fahrenheit, or even higher; but from 68° to 86° Fahrenheit, is the ordinary range. A current of air should be admitted to purify the atmosphere from the fetid emanations of the caterpillars, their excrements, and the decayed leaves. Light is nowise unfavourable; but may be regarded as in some respects advantageous. A spare room should be set apart for the diseased worms.

A few osier mats may suffice while the worms are young, but more are required in proportion as they grow larger, to prevent their getting piled on each other. The supply of leaves must be proportional to the age of the brood, and ought to be increased when nothing but their ribs are left. The very young should be fed with leaves minced small, and should not be troubled with the removal of the litter, which is trifling. At a future stage it must be removed with delicacy, to give the worms more air, on the new wicker frames, without parting them too far.

Before each moulting, the worm has a keen appetite, but during that process it loses it entirely, and falls into a languid state, from which it immediately revives on casting its skin. The pieces of paper are withdrawn from the bottom of the wicker-frames to permit a free transmission of air between their interstices, whenever the worms have become large enough not to fall through them. After the second moulting, they are half an inch long, and may then be transported from the smaller apartment, in which they are hatched, into the larger one, where they are to be reared to maturity. They must be well cleaned from the litter on this occasion, laid upon fresh leaves, and supplied with a succession of them, cut in pieces, every six hours. After the third moult, the worms may be fed with entire leaves; for they are then extremely voracious, and must not be stinted in their diet. The same remark is still more

applicable to the period after the fourth moult. The heat should now be limited to 68° or 70° Fahrenheit. In every period of their existence, the silk worms are liable to a variety of diseases, under which they derive benefit from the exposure of portions of chloride of lime in their nurseries. When they have reached the fifth stage, they cease to eat; they void their excrements, diminish in bulk, become somewhat semi-transparent, abandon the leaves, try to crawl on the upright posts, and to conceal themselves in corners. These symptoms indicate the development of the spinning instinct. Green oak twigs are to be laid in parallel rows on the wicker tablets in the form of little alleys, eighteen inches wide, with their little ramifications interwoven above. The worms of two tablets are to be collected on one, and freed from all their litter. Little coils of paper and of wood shavings are placed alongside of the diligent worms first, and, after a while, of the lazier ones. The creature sets itself to construct its cocoon, throwing about its thread in different directions, forming the floss, filoselle, or outer open net work. But it soon begins its regular operation of winding round about, in nearly parallel lines, a fine thread into an eggshaped form, in the centre of which the caterpillar sits at work. The matter of the silk is liquid in the body of the worm, but it hardens in the air. The twin filaments, which the animal always spins through its double tubular mouth, are agglutinated by that liquid cement. The same matter may be extracted in a lump from the body of the worm, and drawn out artificially into a thin transparent web, or into threads of variable diameters. The cocoons are completed in the course of three or four days, after which they must be removed from the branches and sorted, the finest being reserved for seed worms. The cocoons which are to be unwound must not be allowed to remain with the worms ten or twelve days alive within them; for if the chrysalis has time to come out, the cocoon would be cut through, and be useless. The animal must be killed by suffocation, which is effected either by exposing the cocoons for five days to the sunshine, by placing them in a hot oven, or in the steam of boiling water.

The erection of the first mill in England for the manufacture of silk was at Derby. The original mill, called the Silk Mill to denote its pre-eminence, being the first and largest of its kind ever erected in England, stands upon an island in the river Derwent. Its history remarkably denotes the power of genius, and the vast influence which even the enterprises of an individual has on the commerce of a country. The Italians were long in the exclusive possession of the art of silk throwing, and the merchants of other