Mr Zalmon Storrs mentions, in his letter to Governor Wolcott, that there are at least three varieties of silkworms in Connecticut. The first is the dark brown or flask worm, 'which,' observes he, 'is considered the best, the largest, and makes the most silk. The second a pale white worm, nearly or quite the size of the first, but which does not live so long, or make as much silk; and the third is a smaller, pale white worm, which passes through its transmigration twice in one season, producing two crops of silk; but as it produces less silk than either of the others at one crop, it is not much used, though the silk possesses one property, which that of the others does not; namely, when spun and used in its native state, it retains its clear whiteness, and does not turn yellow by washing and exposure to sun and air.' MS. Letter.

The silkworms are reared in the open air or in laboratories. The first method is followed in some parts of China; and as the mean temperature of that country is not very high, it has been thought that there would not be any danger in adopting it in some parts of Europe. The Austrian government at one time directed the experiment to be tried by some of its regiments on the Illyrian and Wallachian frontiers. Mr Hazzi furnishes, in extenso, the reports of the commanding officers, and they are not of a nature to encourage any farther trial. Count Dandolo constructed, for his own use, a laboratory, which is now imitated in several parts of Italy. It is minutely described in his work Dell' Arte di governare i Bachi da Seta, and the most important details are transcribed or extracted in the congressional document. The principal object to be attended to in the erecting of such a building is, to construct it in such a manner, as to make it possible to regulate the degrees of light and air to be admitted into it, so as to correspond to the variable necessities of the worms. A free circulation of air is, however, the most indispensable condition of any room, or building, in which the business is pursued, on a great or a small scale. Considering the climate of this country, a cool and shady situation would be the principal point to be aimed at. An apparatus, invented by the Rev. Mr Swayne, offers this, among other advantages, that it requires a very moderate space, and that it can easily be kept clean, a circumstance essential to the health and preservation of the worms. Mr Rush's report contains a wood cut of this apparatus.

When the mulberry leaves are about to appear, the eggs are

washed either with the cloth upon which they lie, or after having been carefully scraped off. They are then dried, and as the weather is not at that season warm enough, they must be deposited either in a hot-house, or in a room perfectly dry, the temperature of which can be regulated by means of a thermometer. The most indispensable implements and articles of furniture are a stove, several boxes of thin boards or thick pasteboard, some wicker trays or tables intended to support the boxes, and a few portable ones for transporting the young worms from one place to another. The wicker hurdles must be far enough apart to prevent the insects from wandering from bed to bed. The temperature, during the first two days, ought to be kept up to sixty-four degrees of Fahrenheit, either by artificial heat or by creating a draught to cool the internal air, according to the weather. On each of the following days, till the ninth, the temperature must be increased by two degrees; and on the three following days, it should not exceed eighty-one degrees.

The worms are formed when the eggs begin to whiten. Papers pierced with holes, proportioned to the age of the insect, are then extended upon them, with small twigs of mulberry. Healthy worms, on their first apperance, are of a dark or chestnut color, and never red or black. As their whole existence depends upon the state of forwardness of the tree upon which they feed, and as a sudden change in the weather retards sometimes the shooting of the leaves, the hatching must be regulated accordingly; and the mode of retarding it, is to diminish the heat of the laboratory. Independent of the temperature, a great deal also depends upon the quality of the eggs. The best hatching takes place between the first and third days after the eggs have been laid in the boxes. It is very essential that the worms to be reared come forth on the same day; and those of the first and after the third day are equally useless, and ought to be cast away, since the difference of their growth would render it impossible to attend equally to their necessities. According to Count Dandolo, thirty-seven thousand four hundred and forty eggs weigh an ounce; and the worms proceeding from them require, until their first moulting, a space of about seven feet square; from that time till the second moulting, double that extent; till the third, about five times the first space; and till the fourth, eightytwo feet square. But when there is but a single room for the breeding, a greater attention must be paid to the temperature.

The worms are kept on wider trays, lined with paper, turning upwards at the edges, to prevent their falling out. The temperature ought to be kept at seventy-five degrees, the insects requiring less heat upon growing older. It is highly important however, to shelter them against sudden changes, and against transitions from moderate to violent heat.

In the breeding of no animal, is the exact quantity of food with which it must be supplied, of so great importance as in the rearing of the silkworm. Sanctorius, who passed a portion of his life on a pair of scales to ascertain the effects of perspiration upon the human body, cannot have managed his experiments with greater care than is necessary in the distribution of the mulberry leaves to the newly hatched insects. The silkworms proceeding from an ounce of eggs, consume, in their first age, seven pounds of leaves; in the second, twenty-one pounds; in the third, sixty-nine pounds; in the fourth, two hundred and ten pounds, and in the fifth, one thousand two hundred and eighty-one pounds (French weight). The leaves must be chopped very small during the first period, and gradually less in the three following. At each moulting, the worms eat little for a short time; they become afterwards very voracious, and at last they cease to eat. The quantity of cocoons depends so much on the feeding, that the worms of one ounce of eggs, to produce one hundred and ten or twenty pounds of cocoons, require about one thousand six hundred and fifty pounds of leaf; and when only one thousand and fifty pounds of food have been expended, the same weight of eggs will give only from fifty-five to sixty pounds of cocoons. It is not indifferent whether the same quantity of cocoons proceeds from one or more ounces of eggs, for the quality is, in the one case, always better than in the other.

The following comparative results are mentioned in the document of Congress.

'If one ounce of eggs shall have produced, by the means stated, one hundred and twenty pounds of cocoons, they will be fine; three hundred and sixty, at most, will produce a pound and a half; and eleven or twelve ounces, at most, of these cocoons, will yield an ounce of exquisite, fine silk. When only fifty or sixty pounds of cocoons come from one ounce of eggs, it may generally be presumed, that they are of an inferior quality to the above, and it will require four hundred, at least, to make one pound and a half; and above thirteen ounces of these cocoons, instead of eleven or

twelve ounces, to form one ounce of silk. Moreover, when the worms have not been properly managed, there is no certainty, as to the quantity of the cocoons that will be gathered; and it happens continually, that the same cultivator will, from the same quantity of eggs, and the same quality of the leaves, obtain, at one time, a number of cocoons, at another time few, and sometimes none.' P. 64.

It would be impossible for us to go into any further detail of the rearing of the silkworm. Nothing but a general glance can be given, in the few pages that are allotted to us for treating of a subject so extensive, in which repetitions are unavoidable, and which does not admit of conciseness. Most of the writers on this subject, have, independently of a minute exposition of the daily proceedings in the feeding and treatment of the worm, recapitulated their directions in tables, in which are indicated, in the fewest words that can be employed, the task of each day, though the several ages of the insects; the quantity of food that must be administered; the temperature and the space which the worms require; and the care which must be taken for their cleanliness and the preservation of their health. Such a table may be found in the report of Mr Rush, borrowed from M. Bonafon's Treatise on the rearing of silkworms.' (Paris, 1824.) We regret that our limits do not permit us to lay it before the reader.

We take it now for granted, that the worms have attained their perfect maturity, though many dangers have beset their existence, and a host of enemies,-fowls, mice, rats, weasels, ants, and spiders, may have lain in wait for them, and notwithstanding the various diseases to which they are liable. We suppose that they have already a deeper yellow color, that their rings have a more gold-like hue, and that their muzzle has become of a brighter red than before, which are the signs that they are near the close of their fifth age. The fumigations which must also have taken place during the former ages, should now be repeated twice a day, the air frequently renewed, and the attention to cleanliness redoubled. Generally on the last day of the fifth age they cease to eat, and move their heads as in search of something. They become transparent like ripe, yellow plums, and seek a change of place; their skins become wrinkled, and their bodies soften.

Bundles of twigs, which must be ready and arranged in bunches, are then put above the wicker trays, so as to touch

the lower part of them, and bent in the form of an arch, to enable the worms to climb up without falling. On the first day they often need some assistance in that migration, and much care.

When the worms begin to spin their cocoons, it is very essential that no noise should disturb them in their labor, otherwise they would break their thread, and the cocoon would, consequently, be less perfect. Though the formation of the cocoons requires only three days, or three and a half, it is, nevertheless, thought prudent not to take them from the hurdles before the eighth or ninth day after the worms' first rising. They are then laid in baskets, and the floss, in which they have been formed, is taken off. A selection is made for future breeding, whilst the rest are destined for the reel. For the former purpose, two ounces may be saved out of one pound and a half of male and female cocoons. There are, besides, double cocoons, which, according to Sauvage, invariably produce a moth of each sex, and, according to Mr Nysten, contain moths of both sexes in unequal proportion. The seed cocoons are laid on tables, in layers, disposed in such manner as to be accessible to the air; the temperature of which must not exceed seventy-three degrees. In this state of the atmosphere of the laboratory, they lose in ten days seven and a half per cent. by the dying of the chrysalis alone.

We must omit saying anything in regard to the last period of the silkworms in the state of moths, their coming forth, the laying of the eggs, and the means by which these may be preserved. It will be sufficient to mention, that 'fourteen ounces of cocoons produce, on an average, an ounce of eggs, which supposes a hundred pair of moths.' (Doc. p. 105). Eight pounds of cocoons, of the first quality, yield from sixteen to eighteen and a half ounces of silk. Fifty-five pounds of the second quality produce one hundred and nine ounces of raw silk. In Languedoc, one quintal of cocoons (104 lbs. Amer.) yields from nine to ten pounds of spun silk; and the produce of one ounce of eggs varies between five and ten pounds of silk. (Trans. Soc. Arts. London. vol. XLIII.)

Before the cocoons can be reeled, the floss or loose silk which covers the outside, must be stripped off; the white ones must be separated from the yellow; the good from the useless (and there are nine different qualities in regard to the silk they yield.) The sorted cocoons are thrown into hot water, the VOL. XXVII.-NO. 61.

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