The upper slide a is of paper, and designed to receive the newly-hatched worms. The two slides, bb, are formed of catgut, the threads of which are about one tenth of an inch apart: these are for the insects in their second and third ages. The five slides c c are of wicker-work or netting, and are appropriated to the insects in their more forward stages. Beneath each of the drawers, with the exception of that marked a, other slides of paper are inserted to receive the litter of the worms, which, by this means, may be frequently removed without occasioning any disturbance to the insects. These must not be retained in the upper drawers bb after they have become so large that their litter will not fall through the catgut bottoms: at this time they must be transferred to the wicker or netting slides, which, the inventor imagined would, from their greater number, offer space enough for the accommodation of as many full-grown caterpillars as the upper drawer would contain of those newly hatched. Under this arrangement the litter may be removed as often as the worms are fed.

It has been computed, that three square feet of surface afford ample space for the worms proceeding from an ounce of eggs, until the period of their first sickness is passed; and that this space should be multiplied thrice at each succeeding age. Count Dandolo considered that silkworms would be injuriously crowded in these dimensions, and recommended, that eight square feet should be allotted to the worms during their first age; fifteen feet for the second age; thirty-five feet for the third; eighty-two and a half feet for the fourth; and about two hundred feet for the fifth age. According to these proportions Mr. Swayne's apparatus is very imperfect, but this defect may easily be remedied in practice.

The mulberry leaves given to the newly-hatched brood should be young and tender, and chopped into minute portions. These should be strewed evenly over the whole space of the shelves, that there may not be any unnecessary crowding of the insects in one spot. It is indeed advisable, when -as they sometimes will- the worms get heaped upon one another, that a leaf should be presented over them; to this some will quickly attach themselves, and may then be removed to a less crowded situation.

The worms proceeding from one ounce of eggs will consume six pounds of chopped leaves before their first moulting. Their second age is of shorter duration, but the greater size of the worms requires a more abundant supply of food; and eighteen pounds of leaves, chopped less finely than be

fore, must be given, during its continuance, to the same number. In the third age, sixty pounds of leaves, still a little chopped, must be given; one hundred and eighty pounds will be consumed during their fourth age; and in their fifth and longest age, one thousand and ninety-eight pounds of leaves are devoured by these insects, which, when hatched a few weeks before, weighed less than an ounce.

These quantities are stated on the supposition that the worms are uniformly healthy. If many of them should die in the intermediate time, the weights mentioned will be in excess. On the other hand, if the season should be wet, the leaves will not contain the usual nourishment, with reference to their weight, and more must be given; whereas, if the season should prove more dry than ordinary, the nutriment in the leaves will be greater, and the quantity given may be diminished with advantage. The skill of the cultivator is shown by the weight of silk obtained in proportion to the leaves consumed; and his judgment is tasked to apportion these according to their nutritive properties. There will be no real economy in keeping the consumption of food too low: this, however, is not a common fault, and evils occur much more frequently from over-feeding and waste of leaves.

The worms should be fed with regularity four times a day; and intermediate repasts may be occasionally given, where their appetites appear to be increased in voraciousness. The advantage of chopping the leaves for young worms consists in the economy it introduces. Many thousand insects may, by this means, feed simultaneously upon a few ounces of leaves; whose fresh-cut edges seem better adapted to their powers when newly hatched. If the leaves were given to them whole, a much greater number must be supplied than would be consumed while their freshness lasted, and great waste would be the consequence. The worms will always quit stale leaves for those which are newly gathered. Availing themselves of this fact, some persons provide wire-bottomed frames, which they cover with fresh leaves, and lower them within reach of the worms. These instantly make their way through the reticulations of the wire, and fixing upon the leaves above, the frame may be raised and the litter removed without touching the worms, which might be injured by even the gentlest handling. This plan, as it occasions more trouble, does not appear so eligible as that of Mr. Swayne.

When the silkworms give indications that they are about to spin, little bushes must be provided for the purpose. These

may be of broom, heath, clean bean-stalks, or, in short, any bush or brushwood that is tender and flexible. These should be arranged upright in rows between the shelves, with intervals of fifteen inches between the rows. The bushes should be so high as to be bent by the shelf immediately above into the form of an arch. They should be so spread out, that a supply of air should freely reach every part, and ample space should be afforded for the worms to fix themselves and spin; otherwise, there is great hazard of their forming double cocoons, in which two worms assist in the preparation of one dwelling for both: the silk in these is so much less adapted to the purposes of the reeler, that a double cocoon is worth only one half the price of a single one. Inattention to this point is very common, and occasions constant losses. When the twigs already erected appear to be adequately furnished

with worms, other similar hedges should be formed, parallel to the first. The spaces between the shelves will thus present the appearance of small avenues or arbors covered in at the top.*

The worms at this time require much careful watching, and occasional assistance must be afforded to those which are sluggish, that they may find an eligible spot for forming their cocoons. Those worms which appear still inclined to feed must be supplied with leaves: so long as the slightest inclination for food remains, they will not attempt to form their cocoons. It will sometimes happen, that even after they have climbed among the branches for the purpose of spinning, they will again descend to satisfy their last desire for food.

*Note X.

"I have seen them," says a minute observer, "stop when descending, and remain with the head downwards, the wish to eat having ceased before they reached the bottom." In such a case, they should be turned with their heads upwards, as the contrary position is injurious to them. If, at this time, many appear weak and inert, remaining motionless on the leaves, neither eating nor giving any sign of rising to spin, some means must be taken to stimulate them to the exertion. It was the ancient practice and found to be efficacious for this purpose, to convey some pungent article, such as fried onions, into the apartment, the effluvia from which revived the worms, inciting some to take their last meal, and inducing others, whose desire for food had ceased, to climb the twigs and begin their labors. The same end is now generally and unfailingly attained, by removing the sluggish worms into another apartment, the temperature of which is higher.

All these minute directions may perhaps appear frivolous; but it is only by an unceasing attention to these and the like minutiæ, that any tolerable success can be secured. When all the previous cares and labors of an establishment have been satisfactorily accomplished, if the hedges be not well formed, are irrégular, or too thick in any parts, so as either to impede the circulation of air, or too far to limit the space in proportion to the number of worms, ill success will be sure to follow. Instead of the proper number of fine single cocoons, many will be double, others imperfect or soiled, and even some of the silkworms will be suffocated before the completion of their labors.

It is essential, in every age of the worms, to attend to the regulation of temperature in their apartments; and at no time is this more necessary than while they are forming their cocoons. If, at this time, they are exposed to much cold, they desist from their labors. Should the balls be sufficiently thin, the insects may be discerned, either quite inactive, or moving very slowly. On the temperature being raised, they will immediately resume their work with renewed activity, and will once more desist, if the cold be again allowed to exert its influence. After they have remained inactive from this cause for a short time, they put off their caterpillar form, and assume that of the chrysalis, without having sufficient energy to complete their silken covering.

The fifth volume of the transactions of the Society for the Encouragement of Arts, &c. contains a letter upon this subL

ject from a gentleman, who relates, that in the summer of 1786 he had successfully reared to their full growth more than thirty thousand silkworms, when at the beginning of July, and just as they appeared about to spin, a chilling northeast wind set in, and many of the worms became chrysalides, without attempting to spin. On the examination of these, it appeared that the glutinous matter in their silk reservoirs had become so congealed by the cold, as to resemble strong tendons, both in appearance and tenacity; which sufficiently accounted for the inability of the insects to draw forth the silk in filaments. Thousands of the worms changed in this profitless manner daily, until at length, the survivors being removed into an apartment artificially warmed, they immediately applied themselves to the performance of their usual functions. It is desirable that while silkworms are in the act of spinning, the temperature of their apartment should be maintained as high as 70 degrees, and it is at the same time equally important that free ventilation should be secured.

The opinion has been very generally entertained that violent noise disturbs, and injuriously affects the worms, and that any sudden report, as of fire-arms or thunder, will cause them to fall from their arbors. The peasants in Italy who attend on silkworms are so strongly of this opinion, that if the caterpillars omit to rise and spin after thunder has been heard, they consider its noise as the sole reason of the failure: they are always desirous of removing every cause for noise from about the establishment. This opinion appears, however, to be badly founded, and has been satisfactorily refuted by persons who have made experiments to ascertain the fact. Silkworms have been reared in all the bustle of a town, exposed to the barking of dogs, and to concerts of music, without in any way exhibiting signs of being affected by the noise, The following statement is conclusive. It is taken from the "Cours d'Agriculture," written by Monsieur Rozier, and recounts an experiment performed in the establishment of Monsieur Thomé, a considerable silk cultivator, and one of the earliest writers on the subject. These gentlemen, Messrs. Rozier and Thomé, in the presence of many witnesses, fired several pistol-shots in the apartment where silkworms were either spinning, or rising preparatory to their labor; and the only worm that dropped was evidently a sickly insect, that could not have formed its cocoon under any circumstances.

It is seldom that any opinion upon a point of practice is entertained, without some ground for its existence. The