a very soft, fine, bright thread, the work of an insect called bombyx, or the silk worm.
As the silk worm is a native of China, the culture of silk in ancient times was entirely confined to that country. We are told that the empresses, surrounded by their women, spent their leisure hours in hatching and rearing silk worms, and in weaving tissues and silk veils. That this example was soon imitated by persons of all ranks, we have reason to conclude; for we are informed that the Chinese, who were formerly clothed in skins, in a short time after were dressed in vestments of silk. Till the reign of Justinian, the silk worm was unknown beyond the territories of China, but silk was introduced into Persia long before that period. After the conquest of the Persian empire by Alexander the Great, this valuable commodity was brought into Greece, and thence conveyed to Rome. The first of the Roman writers extant by whom silk is mentioned, are Virgil and Horace; but it is probable that neither of them knew the nature from what country it was obtained, nor how it was produced. By some of the ancients it was supposed to be a fine down adhering to the leaves of certain trees or flowers. Others imagined it to be a delicate species of wool or cotton; and even those who had learned that it was the work of an insect, show by their descriptions that they had no distinct idea of the manner in which it was formed. Among the Romans, silk was deemed a dress too expensive and too delicate for men, and was appropriated wholly to women of eminent rank and opulence. Elagabalus is said to have been the first man among the Romans who wore a garment of fine silk: Aurelian complained that a pound of silk was sold at Rome for 12 ounces of gold; and it is said he refused to give his wife permission to wear it on account of its exorbitant price.
For several centuries the Persians supplied the Roman empire with the silks of China. Caravans traversed the whole latitude of Asia, in 243 days, from the Chinese ocean to the sea-coast of Syria, carrying fine silk. Sometimes it was conveyed to the Indian ports of Guzerat and Malabar, and thence transported by sea to the Persian Gulph. The Persians, with the usual rapacity of monopolists, raised the price of silk to such an exorbitant height, that Justinian, eager not only to obtain a full and certain supply of a commodity which was become of indispensible use, but solicitous to deliver the commerce of his subjects from the exactions of his enemies, endeavoured, by means of his ally, the Christian monarch of Abyssinia, to wrest some portion of the silk trade from the Persians. In this attempt he failed; but when he least expected it, he, by an unforeseen event, attained, in far greater measure, the object which he had in view. Two Persian monks having been employed as missionaries in some of the Christian churches, which were established (as we are informed by Cosmas) in different parts of India, had penetrated into the country of the Seres, or China. There they observed the labours of the silk worm, and became acquainted with all the arts of man in working up its productions into such a variety of elegant fabrics. The prospect of gain, or perhaps an indignant zeal, excited by seeing this lucrative branch of commerce engrossed by unbelieving nations, nations, prompted them to repair to Constantinople. There they explained to the emperor the origin of silk, as well as the various modes of preparing and manufacturing it, mysteries hitherto unknown, or very imperfectly understood in Europe; and encouraged by his liberal promises, they undertook to bring to the capital a sufficient number of those wonderful insects, to whose labours man is so much indebted. This they accomplished, by conveying the eggs of the silk worm in a hollow cane. They were hatched by the heat of a dunghill, fed with the leaves of a wild mulberry tree, and they multiplied and worked in the same manner as in those climates where they first became objects of human attention and care. Vast numbers of these insects were soon reared in different parts of Greece, particularly in the Peloponnesus. Sicily afterwards undertook to breed silk worms with equal success, and was imitated from time to time, in several towns of Italy. In all these places extensive manufactures were established and carried on with silk of domestic production. The demand for silk from the east diminished of course, the subjects of the Greek emperors were no longer obliged to have recourse to the Persians for a supply of it, and a considerable change took place in the nature of the commercial intercourse between Europe and India.
As silk is the production of a worm, it will be necessary to give a description of its nature and mode of manufacturing. But before we give any account of the most approved methods of managing silk worms in Europe, it will be proper to present a short description of the methods practised in China, the original country of the silk worm. These are two: they either permit them to remain at liberty on mulberry trees, or keep them in rooms. As the finest silk is produced by worms confined in rooms, and as the first method is very simple, it will suffice to describe the second.
To begin with the eggs, which are laid on large sheets of paper, to which they firmly adhere. The sheets are hung up on a beam of the room, with the eggs inward, and the windows are opened in the front to admit the wind; but no hempen ropes must ever come near the worms or their eggs. After some days the sheets are taken down, rolled up loosely with the eggs inward, and then hung up again, during the summer and autumn. At the end of December, or the beginning of January, the eggs are put into cold water, with a little salt dissolved in it. Two days after they take them out, hang them up again, and when dry roll them a little tighter, and enclose each separately, standing on one end in an earthen vessel. Some put them into a lye made of mulberry tree ashes, and then lay them some moments in snow-water, or else hang them up three nights on a mulberry tree to receive the snow or rain, if not too violent. The time of hatching them is when the leaves of the mulberry trees begin to open, for they are hatched or impeded according to the different degrees of heat or cold to which they are exposed. When they are ready to come forth, the eggs fwell, and become a little pointed.
The third day before they are hatched, the rolls of paper are taken out of the vessel, stretched out, and hung up with their backs toward the sun, till they receive a kindly warmth; and then being rolled up close, they are set upright in a vessel in a warm place. This is repeated the next day, and the eggs change to an ash-grey. They then put two sheets together, and rolling them close tie the ends.
The third day, towards night, the sheets are unrolled and stretched on a fine mat, when the eggs appear blackish. They then roll three sheets together, and carry them into a pretty warm place, sheltered from the south wind. The next day the people taking out the rolls, and opening them, find them full of worms like small black ants.
The apartment chosen for silk worms is on a dry ground, in a pure air, and free from noise. The rooms are square, and very close, for the sake of warmth; the door faces the south, and is covered with a double mat, to keep out the cold; yet there should be a window on every side, that when it is thought necessary the air may have a free passage. In opening a window to let in a refreshing breeze, care must be taken to keep out the gnats and flies. The room must be furnished with nine or ten rows of frames, about nine inches one above the other. On these they place rush hurdles, upon which the worms are fed till they are ready to spin; and, to preserve a regular heat, stove fires are placed at the corners of the room, or else a warming pan is carried up and down it; but it must not have the least flame or smoke. Cow-dung dried in the sun is esteemed the most proper fuel.
The worms eat equally day and night. The Chinese give them on the first day forty-eight meals; that is, one every half hour; the next thirty; the third day they have still less. As cloudy and rainy weather takes away their stomach, just before their repa't a wisp of very dry straw, the flame of which must be all alike, is held over the worms to free them from the cold and moisture that benumbs them, or else the blinds are taken from the windows to let in the full day-light.
Eating so often hastes their growth, on which the chief profit of the silk worm depends. If they come to maturity in 23 or 25 days, a large sheet of paper covered with worms, which at their first coming from the eggs weigh little more than a drachm, will produce 25 ounces of silk; but if not till 28 days, they then yield only 20 ounces; and if they are a month or 40 days in growing, they then produce but ten.
They are kept extremely clean, and are often removed; and when they are pretty well grown, the worms belonging to one hurdle are divided into three, afterwards they are placed on six, and so on to the number of 20 or more; for being full of humours, they must be kept at a due distance from each other. The critical moment for removing them is when they are of a bright yellow and ready to spin; they must be surrounded with mats at a small distance, which must cover the top of the place to keep off the outward air; and because they love to work in the dark. However, after the third day's labour, the mats are taken away from one o'clock till three, but the rays of the sun must not shine upon them. They are at this time covered with the sheets of paper that were used on the hurdles.
The cocoons are completed in seven days, after which the worm is metamorphosed into a chrysalis; the cocoons are then gathered, and laid in heaps, having first set apart those designed for propagation upon a hurdle, in a cool airy place. The next care is to kill the moths in those cones which are not to be bored. The best way of doing this is to fill large earthen vessels with cones. cones in layers of ten pounds each, throwing in four ounces of salt with every layer, and covering it with large dry leaves like those of the water-lily, and closely stopping the mouth of the vessels. But in laying the cones into the vessels, they separate the long, white, and glittering ones, which yield a very fine silk, from those that are thick, dark, and of the colour of the skin of an onion, which produce a coarser silk.
The silk worm is a species of caterpillar, which, like all others of the same class, undergoes a variety of changes, that, to persons who are not acquainted with objects of this kind, will appear to be not a little surprising.
It is produced from a yellowish coloured egg, about the size of a small pin head, which has been laid by a kind of greyish coloured moth, which the vulgar confound with the butterfly.
These eggs, in the temperature of this climate, if kept beyond the reach of the fire and sun shine, may be preserved during the whole of the winter and spring months without danger of hatching; and even in summer they may easily be prevented from hatching if they be kept in a cool place; but in warmer climates it is scarcely possible to preserve them from hatching, even for a few days, or from drying so much as to destroy them. Hence it is easy for a native of Britain to keep the eggs till the food on which the worm is to feed be ready for that purpose. When this food is in perfection, the eggs need only be exposed to the sun for a day or two, when they will be hatched with great facility.
When the animal is first protruded from the egg, it is a small black worm, which is active, and naturally ascends to the top of the heap in search of food. At this stage of his growth the silk worm requires to be fed with the youngest and most tender leaves. On these leaves, if good, he will feed very freely for about eight days, during which period he increases in size to about a quarter of an inch in length. He is then attacked with his first sickness, which consists in a kind of lethargic sleep for about three days continuance; during which time he refuses to eat, and changes his skin, preserving the same bulk. This sleep being over, he begins to eat again, during five days, at which term he is grown to the size of full half an inch in length; after which follows a second sickness in every respect like the former.
He then feeds for other five days; during which time he will have increased to about three quarters of an inch in length, when he is attacked with his third sickness. This being over, he begins to eat again, and continues to do so for five days more, when he is attacked by his fourth sickness, at which time he is arrived at his full growth. When he recovers this sickness, he feeds once more during five days with a most voracious appetite; after which he disdains his food, becomes transparent, a little on the yellowish cast, and leaves his silky traces on the leaves where he passes. These signs denote that he is ready to begin his cocoon, and will eat no more.
Thus it appears that the whole duration of the life of the worm, in this state of its existence, in our climate, is usually about 46 days; 28 of which days he takes food, and remains in his sick or torpid state 18; but it is to be observed, that during warm weather the periods of sickness are shortened, and in cold weather lengthened, above the terms here specified. In very hot climates it may be said to live faster, and sooner to attain maturity, than in those that are colder. Dr Anderson informs us, that at Madras the worm undergoes its whole evolutions in the space of 22 days. It appears, however, that it feeds fully as many days in India as in Europe, the difference being entirely occasioned by shortening the period of sickness. The longest sickness he had seen them experience there did not exceed two days; and during summer it only lasts a few hours.
When the worm has attained its full growth, it searches about for a convenient place for forming its cocoon, and mounts upon any branches or twigs that are put in its way for that purpose. After about two days spent in this manner, it settles in its place, and forms the cocoon, by winding the silk which it draws from its bowels round itself into an oblong roundish ball.
During this operation it gradually loses the appearance of a worm; its length is much contracted, and its sickness augmented. By the time the work is finished, it is found to be transformed into an oblong roundish ball, covered with a smooth shelly skin, and appears to be perfectly dead. In this state of existence it is called an aurelia. Many animals in this state may be often seen sticking on the walls of out-houses, somewhat resembling a small bean.
In this state it remains for several days entirely motionless in the heart of the cocoon, after which it bursts like an egg hatching, and from that comes forth a heavy dull looking moth with wings; but these wings it never uses for flying; it only crawls slowly about in the place it has been hatched. This creature forces its way through the silk covering which the worm had woven, goes immediately in quest of its mate, after which the female lays her eggs; and both male and female, without taking food in this stage of their existence, die in a very short time.
The silk worm, when at its full size, is from an inch and a quarter to an inch and a half in length, and about half an inch in circumference. He is either of a milk or pearl colour, or blackish; these last are esteemed the best. His body is divided into seven rings, to each of which are joined two very short feet. He has a small point like a thorn exactly above the anus. The substance which forms the silk is in his stomach, which is very long, wound up, as it were, upon two spindles, as some say, and surrounded with a gum, commonly yellowish, sometimes white, but seldom greenish. When the worm spins its cocoon, he winds off a thread from each of his spindles, and joins them afterwards by means of two hooks which are placed in his mouth, so that the cocoon is formed of a double thread. Having opened a silk worm, you may take out the spindles, which are folded up in three plaits, and, on stretching them out, and drawing each extremity, you may extend them to near two ells in length. If you then scrape the thread so stretched out with your nail, you scrape off the gum, which is very like bees wax, and performs the same office to the silk it covers as gold leaf does to the ingot of silver it surrounds, when drawn out by the wire drawer. This thread, which is extremely strong and even, is about the thickness of a middling pin.
Of silk worms, as of most other animals, there is a particular considerable variety of breeds, some of which are much attention more hardy, and possess qualities considerably different from others. This is a particular of much importance to silk worms. to be adverted to at the time of beginning to breed these creatures in any place; for it will make a great difference in the profit on the whole to the undertaker if he rears a good or a bad sort (a). This is a department in respect to the economy of animals that has been in every case much less adverted to than it deserves; and in particular with regard to the silk worm it has been almost entirely overlooked. A few eggs of the silk worm can be easily transported by post in a letter from any part of Europe to another, especially during the winter season. It would therefore be an easy matter for any patriotic society, such as the Society of Arts in London, to obtain a specimen of the eggs from every country in which silk is now reared, to put these under the care of a person who could be depended upon, and who undertook the management of them, with orders to keep each kind distinct from another, and advert to every particular that occurred in their management, so as to make a fair estimate of their respective merits. By these means the best might be selected, and those of inferior value rejected. Forty or fifty of each sort might be enough for the experiment; but it ought to be repeated several times before conclusions could be drawn from it that might be altogether relied upon; for it is well known that a variation of circumstances will make a change in the result; and it is by no means certain that the same particular would affect those of one breed exactly in the same manner as it would do those of a different breed. One may be more hardy with regard to cold, another more delicate in respect to food, and so on. It is experience alone that can ascertain the circumstances here inquired for.
From the above-mentioned particulars, it is evident, that the management of silk worms must be very different in hot climates from what is required in those that are colder. At Madras, it appears from Dr Anderson's experiments that it is very difficult to prevent the eggs from hatching for a very few days, so that many generations of them must be propagated in one year. "In this hottest season," says he, in a letter to Sir Joseph Banks, dated July 6, 1791, "the shortest time I have been able to remark for the whole evolutions of the silk worm is 40 days; that is to say, six days an egg, 22 a worm, 11 a grub in the cocoon, and one moth or butterfly." Fortunately, where the climate forces early their production so rapidly, nature hath been equally provident of food for their subsistence; for in these regions the mulberry continues to grow and push out leaves throughout the whole year. Though the silk worm be a native of China, there is no doubt but it might easily be propagated perhaps in most parts of the temperate zones. The eggs of this insect, indeed, require a considerable degree of warmth to hatch them, but they can also endure a severe frost. No less than 540 lbs of silk was raised in 1789 in the cold, sandy territories of Prussia. In the province of Pekin, in China, where great quantities of silk are fabricated, the winter is much colder than even in Scotland. From the information of some Russians who were sent thither to learn the Chinese language, we find that Reaumur's thermometer was observed from 10 to 15, and even 20 degrees below the freezing point. Nor is it difficult to rear the food of the silk worm in a temperate clime. The mulberry tree is a hardy vegetable, which bears, without injury, the winters of Sweden, and even of Siberia. Of the seven species of the mulberry (see Morus) enumerated by Linnæus, four of these (viz. the white, red, black, and Tartarian), there is every reason to believe could be reared both in Britain and Ireland. The white grows in Sweden; the red is abundant round Quebec; the black delights in bleak situations, exposed to wind on the sea shore; and the Tartarian mulberry is represented as growing in the chilly regions of Siberia.
As to the superior qualities of the different species, whether probably there is very little to be pointed out amongst all species of mulberry, except what may be drawn from the following fact: that superior to the first three are laid down together, the silk worm others will first eat the white, then the red, and next the black, in the order of the tenderness of the leaves. The Tartarian seems to hold as high a place in its esteem as either the red or black; but all must yield to the white, which seems to be its natural food.
In Calabria the red mulberry is used; in Valencia the white; and in Granada, where excellent silk is produced, the mulberries are all black. The white seems to prosper very well in a moist stiff soil; the black agrees well with a dry, sandy, or gravelly soil; and the white is most luxuriant in a moist rich loam.
It may justly be asserted, that Britain possesses some advantages in the raising of raw silk which are not enjoyed by warmer countries. Even in the south of France, Mr Arthur Young informs us, the mulberry leaves are often nipped by frost in the bud; but this is for raising scarcely ever the case with us. It is well known that silk, thunder and lightning are hurtful to the silk worm. Now our climate can boast that it is almost wholly exempted from those dreadful storms of thunder and lightning which prevail so much in hot climates. Nature has then furnished us with every thing requisite for the silk manufacture; it remains only for us to improve the advantages which we possess. Let mulberry trees be planted by proprietors of lands, and let a few persons
(a) As the success of the silk manufacture must depend on the breed of worms, it is of great consequence to bring them from those countries where they are reckoned best.
Mr Andrew Wright, an ingenious silk manufacturer of Paisley, has given the following directions for conveying the eggs of the silk worm from distant countries by sea: As soon as the moth has laid her eggs, dry them immediately, and put them into glass vials; seal them so close that damp air or water will not penetrate into them. Put these phials that contain the eggs into earthen pots filled with cold water; and as often as the water becomes warm renew it. Place the earthen vessels in the coldest place of the ship, and let them remain until the end of the voyage. It must be observed, that the ship chosen for this purpose ought to be one that would arrive in Britain in the months of June or July. of skill and attention devote their time to the raising of silk worms. This is an employment that will not interfere with any manufacture already established; on the contrary, it would afford a respectable, a lucrative, and agreeable employment to ladies, or to females in general, who have at present too few professions to which they can apply. The society instituted at London for the encouragement of arts, manufactures, and commerce, much to their honour, have offered premiums to those who shall plant a certain number of mulberry trees.
The following method of raising mulberry trees from seed is practised in the south of France, and has been repeated with success in the East Indies by Dr Anderson of Madras. "Take the ripe berries of the mulberry when it is full of juice and of seeds. Next take a rough horse hair line or rope, such as we dry linen on, and with a good handful of ripe mulberries run your hand along the line bruising the berries and mashing them as much as possible as your hand runs along, so that the pulp and seeds of the berries may adhere in great abundance to the rope or hair line. Next dig a trench in the ground where you wish to plant them, much like what is practised in kitchen gardens in England for crops of various kinds. Next cut the rope or hair line into lengths according to the length of the trench you think fit to make, and plunge the line full of mashed berries into the trench, and then cover it over well with earth, always remembering afterwards to water it well, which is essential to the success. The seeds of the berries thus sown will grow, and soon shoot out young suckers, which will bear young leaves, which are the best food for the silk worm.
"The facility and rapidity with which young leaves may by this means be produced is evident, for as many rows of trenches may thus be filled as can be wished; and it can never be necessary to have mulberry trees higher than our raspberry, currants, or gooseberry bushes. Whenever they get beyond that, they lose their value; and if these trenches succeed, you may have a supply coming fresh up day after day, or any quantity you please." Thus abundance of these trees might be reared. But as mulberry trees are not yet found in abundance in this country, it were to be wished that some other food could be substituted in their place: attempts have accordingly been made by those who have reared silk worms, and it has been found possible to support the silk worm upon lettuce (a).
Miss Henrietta Rhodes, a lady who has made some successful experiments on raising silk worms in England, had found that the silk worm could with safety be kept on lettuce for some time. This is pretty generally known by ladies who have turned their attention to this subject; but she found that in general they could not with safety be kept upon that food above three weeks. If longer fed upon that plant, the worms for the most part die without spinning a web at all. She found, however, that they did not always die, but that in some cases they produced very good cocoons, even when fed entirely on lettuce. She therefore with reason suspected that the death of the animal must be occasioned by some extraneous circumstance, and not from the poisonous quality of the food itself; the circumstance she suspected, from some incidental observations, was the coldness of that food; and therefore the thought it was impossible, but if they were kept in a very warm place, while fed on lettuce, they might attain, in all cases, a due perfection.
General Mordaunt having been informed of this conjecture, resolved to try the experiment. He got some silk worms eggs, had them hatched in his hot-house, and caused them to be all fed upon lettuce and nothing else. They prospered as well as any worms could do, few or none of them died; and they afforded as fine cocoons as if they had been fed upon mulberry leaves. As far as one experiment can go, this affords a very exhilarating prospect in many points of view. If one kind of food has been noxious, merely on account of an improper temperature, others may be found which have been hurtful only from a similar cause; so that it is not impossible but we may at last find that this delicate creature may be supported by a variety of kinds of food. Few, however, could be more easily obtained than lettuce; and this plant, when cabbaged (the cobs, or ice lettuce especially), would possess one quality that the mulberry leaf never can possess, from the want of which many millions of worms die in those countries where silk is now reared; for it is observed, that when the leaves are gathered wet, it is scarcely possible to preserve the worms alive for any length of time; so that during a continuance of rainy weather many of them are unavoidably cut off; but a lettuce, when cabbaged, resists moisture. If gathered, even during rain, the heart of it is dry; so that if the outer leaves be thrown aside at that time, the worms would be continued in perfect health. The expense, too, of cultivating and gathering lettuce, would be so much less than that of gathering mulberry leaves, as to occasion a saving that would be much more than sufficient to counterbalance the expense of heating the conservatory, as a little reflection will show.
But the great point to be now ascertained is, whether it is a fact that worms fed on lettuce, if kept in a due temperature, will continue in good health, in general, till they shall have perfected their cocoon? One experiment is too little to establish this fact with perfect certainty. It would therefore be necessary that more experiments should be made on this subject.
It is said that Dr Lodovico Bellardi, a learned and ingenious botanist of Turin, has, after a number of experiments, discovered a new method of feeding silk worms, when they are hatched before the mulberry leaves have produced leaves, or when it happens that the frost destroys the tender branches. This new method consists in giving the worms dried leaves of the mulberry-tree. One would think that this dry nourishment
(a) It is not improbable, says Dr Anderson, to whose valuable work entitled the Bee, we have been much indebted in the drawing up of this article, that other kinds of food may be found which will answer the same purpose. The chicory intybus and common endive might be tried, as they have the same lacteal quality with the lettuce. ment would not be much relished by these insects; but repeated experiments made by our author, prove that they prefer it to any other, and eat it with the greatest avidity. The mulberry leaves must be gathered about the end of autumn, before the frosts commence, in dry weather, and at times when the heat is greatest. They must be dried afterwards in the sun, by spreading them upon large cloths, and laid up in a dry place after they have been reduced to powder. When it is necessary to give this powder to the worms, it should be gently moistened with a little water, and a thin coat of it must be placed around the young worms, which will immediately begin to feed upon it.
We have mentioned all the different kinds of food, which, as far as we have heard, have been tried with any success to nourish the silk worm; not, however, with great confidence, but as experiments which it might be worth while carefully to consider and perform. We must not omit to mention that one person, who has had much experience in the managing of silk worms, assures us, that the silk produced from any other food than mulberry leaves is of an inferior quality, and that the worms are fickle. We think, however, that there is reason to suppose that the experiment has not been skillfully performed; and therefore, before every other food except mulberry leaves is discarded, the experiment ought to be performed with more attention and care.
We know that many animals in a domestic state can live upon food very different from that which supported them when running wild in the fields. Certain it is, however, that every animal, in its state of nature, partakes of a food peculiar to itself, which is rejected by other animals as if it were of a poisonous quality; and it may be mentioned as a curious fact, as well as an admirable instance of the care of that Being who feeds the fowls of heaven, that notwithstanding the numberless insects that prey upon animals and vegetables, the mulberry tree is left untouched by them all, as the exclusive property of the silk worm, the chief of the insect tribe, which toils and spins for the use of man.
Having now considered the food proper for the silk worm, we shall next consider what situation is most favourable to them. In the opinion of some persons in this country who have been in the practice of rearing silk worms, they ought always to be kept in a dry place, well sheltered, and possessing a considerable degree of warmth, and which is not exposed to sudden transitions from heat to cold. If the weather be too cold, a small fire must be made; this is of most importance when the worms are ready for spinning. A southern exposure is therefore preferable. Some think light is of great utility to silk worms, others think that they thrive better in the dark. As to what arrangements are best accommodated for promoting the health of silk worms, and most convenient for those who have the care of them, they may be various according to the extent of the manufacture or the wealth of the proprietors. Silk worms may be kept in boxes or in shelves. When shelves are to be used, they may be constructed in the following manner: The shelves may be of wicker, ranged at the distance of a foot and a half, and fixed in the middle of the room; their breadth ought to be such, that any person can easily reach to the middle from either side. This is perhaps the simplest and cheapest apparatus for rearing silk worms; but there is another apparatus which may be recommended to those who are anxious to unite some degree of elegance with convenience. This apparatus is the invention of the Rev. George Swayne of Pucklechurch, a gentleman who, greatly to his honour, has studied this subject much, in order to find out the way for promoting the culture of silk among the poor. This apparatus, with the description of it, we have borrowed from that valuable and patriotic work, the Transactions of the Society for encouraging Arts, Manufactures, and Commerce, Vol. VII. p. 148. The apparatus consists of a wooden frame four feet two inches high, each side 16 inches and a half wide, divided into eight partitions by small pieces of wood which form grooves, into which the slides run, and are thus easily thrust into or drawn out of the frame. The upper slide (a) in Plate CCCCLXVI. is the model sent to the society by Mr. Swayne is of paper only, and designed to receive the worms as soon as hatched; the two next (b, b) are of catgut, the threads about one-tenth of an inch distant from each other; these are for the insects when a little advanced in size; the five lower ones, marked c, c, c, c, c, are of wicker work; but, as Mr. Swayne afterwards found, netting may be substituted with advantage instead of wicker bottoms. Under each of these, as well as under those of catgut, are sliders made of paper, to prevent the dung of the worms from falling on those feeding below them.
The management of silk worms is next to be attended to. The proper time for hatching them is when the leaves of the mulberry are full grown, or nearly so; that as soon as these insects are capable of receiving food they may obtain it in abundance. To attempt to hatch them sooner would be hurtful, as the weather would not be sufficiently warm. Besides, as leaves are necessary to the life of a vegetable, if the young leaves of the mulberry-tree are cropped as soon as they are unfolded, the tree will be so much weakened as to be incapable of producing so many leaves as it would otherwise have done; and if this practice be frequently repeated, will inevitably be destroyed.
When the proper season is arrived, the eggs may be hatched either by the heat of the sun, when it happens to be strong enough, or by placing them in a small room moderately heated by a stove or fire; and after being exposed for six or seven days to a gentle heat, the silk worm issues from the egg in the form of a small black hairy caterpillar. When Mr. Swayne's apparatus is used, the worms are to be kept on the drawers with paper bottoms till they are grown so large as not readily to creep through the gauze-bottomed drawers; they are then to be placed on those drawers, where they are to remain till their excrements are so large as not readily to fall through; when this is the case, they must be removed to the drawers with the wicker or netting bottoms, and fed theron till they show symptoms of being about to spin. It is scarcely necessary to mention, that the paper slides beneath the gauze and wicker drawers are intended to receive the dung, which should be emptied as often as the worms are fed, at least once a day; or to direct, that when the worms are fed, the slides are to be first drawn out a considerable way, and the drawers to rest upon them.
It has been already mentioned, that wet or damp food is exceedingly prejudicial to these insects. It produces contagious and fatal diseases. To prevent the necessity of giving them wet or damp food, attention is directed. ought to be paid to the weather, so that when there is an immediate prospect of rain, a sufficient quantity of leaves may be gathered to serve the worms two or three days. In this country, the leaves of the black or red mulberry tree may be preferred good for food, although kept four or five days, by the following method: When new gathered, lay them loosely in glazed earthen vessels, place these in a cold place, well aired, not exposed to drought.
The utmost attention must be paid to preserve the place where silk worms are kept as clean as possible: the house or room must be well ventilated, that no noxious vapors be accumulated. By some experiments of M. Faujas de St Fond, which are recorded in his history of Languedoc, it appears that the silk worm is much injured by foul air. All decayed leaves must be removed from them, as it is now well known that they emit bad air in great abundance.
One of the most difficult branches of the management of silk worms has hitherto been the cleaning without bruising them. To avoid this inconvenience, the peasants in France and Italy frequently allow the whole litter to remain without ever cleaning them, which is the cause of that unwholesome stench that has been often remarked by those who visit the places for rearing silk worms in these countries. This difficulty may be effectually removed by providing a net, or, what would be still better, a wire-bottomed frame, wrought into large meshes like a riddle. Have that made of a size exactly sufficient to cover the wooden box in which the worms are kept. When you mean to shift them, spread fresh leaves into the wire basket; and let it down gently over the worms till it comes within their reach. They no sooner perceive the fresh food than they abandon the rubbish below, and creep through the meshes, so as to fix themselves upon the leaves; then by gently raising the fresh basket, and drawing out the board below (which ought to be made to slip out like the flip bottom of a bird's cage), you get off all the excrements and decayed leaves, without incommending the worms in the smallest degree; and along with the litter you will draw off an inch or two in depth of the foulest mephitic vapors. To get entirely rid of these, the board, when thus taken out, should be carried without doors, and there cleaned; and the flip board immediately replaced to receive all the excrements and offals. After it is replaced, the wire frame that had been elevated a little, may be allowed to descend to a convenient distance above the board without touching it. Thus will there be left a vacant space for the mephitic air to fall below the worms, so as to allow them to inhabit a wholesome region of the atmosphere.
When a fresh supply of food is to be given before cleaning, the wire frame ought to be let down as close to the board as can be fairly done, and another wire-bottomed frame put over it, with fresh leaves, as before described. When the worms have abandoned that in their turn, let the flip-board, together with the lower wire frame, be drawn out and removed, and so on as often as necessary. To admit of this alternate change, every table, consisting of one flip-board, ought to have two sets of wire-bottomed frames of the same size; the flip board to be always put into its place immediately after it is cleaned, and the wire frames referred to be afterwards placed over the other. By this mode of management, it is probable that the worms would be saved from the diseases engendered by the mephitic air, and the numerous deaths that are the consequence of it avoided.
Dr Anderson, to whom we have already acknowledged our obligations, and to whom this country has been much indebted for valuable works on agriculture, the fisheries, &c., advises those who have the management of silk worms to throw a thin stratum of fresh flaked quicklime upon the flip-board each time it is cleaned, immediately before it is put into its place. This would absorb the mephitic gas, for as soon as it is generated it would descend upon the surface of the quicklime. Thus would the worms be kept continually in an atmosphere of pure air (c). Were the walls of the apartments to be frequently washed with quicklime and water, it would tend much to promote cleanliness at a small expense, and augment the healthiness of the worms as well as that of the persons who attend them.
When the silk worm refuses its food, and leaves silky traces on the leaves over which it passes, it is a proof that it is ready to begin its cocoon. It is now necessary to form a new receptacle, which is commonly done by pinning together papers in the shape of inverted cones with broad bases. "This method (says Mr Swayne), being to spin, where there are many worms, is exceedingly tedious, translations wastes much paper, and uses a large number of pins; of the Society for the Encouragement of Arts, vol. vii. p. 123; thod I make use of is, to roll a small piece of paper (an uncut octavo leaf, such as that of an old magazine, is sufficient
(c) To put this question beyond a doubt, Mr Blancard made the following comparative experiments, which were several times repeated. "I procured (says he) four glass jars nine inches high and five in diameter, closing the mouth with cork stoppers. After which I placed in each of them, in their second life (so may be translated which means the stage between the different sicknesses), twelve silk worms, which were fed four times a day; and which I confined in this kind of prison all their life, without taking away either their dead companions or their ordure or litter. I sprinkled with chalk the worms of only two of these jars, and kept the two others to compare with them.
"In those without lime, I never obtained neither more nor less than three small and imperfect cocoons (chiques ou bouffards), and in the two that were sprinkled with lime, I had very often twelve, and never less than nine fine full-sized firm cocoons."
This experiment affords the most satisfactory proof of the utility of this process. From a number of trials he found, that even when the worms were covered with a very large proportion of lime, they never were in any way inconvenienced by it. The cocoons which are kept for breeding are called royal cocoons. For selecting and preserving these, we have been favoured with some valuable instructions by Mr Wright of Paisley, which we shall present to our readers.
The largest and best cocoons ought to be selected for breed, about an equal number of males and females; the cocoons that contain the former are sharper pointed at the ends than those that contain the latter. Although it should happen that there are more females than males, little inconvenience or ill consequences can arise from it, as one male will serve two or three females, if the time of their coming out of the cocoons allow. About 12 or 15 days after they begin to spin, the cocoons for breed may be laid on sheets of white paper; about this time the moth opens for itself a pallage through the end of its cocoon, and flies out. When the female has laid her eggs, which on an average may amount to 250, they are spread upon sheets of paper and hung up to dry in some place where they may not be exposed to the heat of the sun; after being dried they must be kept in a cool well-ventilated place, where neither vapours nor moisture can reach them. That they may be preserved from external accidents, as insects of different kinds will destroy them, and mice is their enemy in all the stages of their existence, they should be kept in stone pots or glass bottles with their mouths stoppered, and there remain until brought out next season to be hatched.
The cocoons from which the silk is to be immediately wound must be exposed to the heat of an oven, in order to kill the chrysalis or aurelia, which would otherwise eat its way through the cocoon, and render it useless. The following directions are given for managing this process by one of the first silk manufacturers in Italy.
Put your cocoons in long shallow baskets, and fill them up within an inch of the top. You then cover them with paper, and put a wrapper over that. These baskets are to be disposed in an oven, whose heat is as near as can be that of an oven from which the bread is just drawn after being baked. When your cocoons have remained therein near an hour, you must draw them out; and to see whether all the worms are dead, draw out a dupion from the middle of your basket and open it; if the worm be dead, you may conclude all the rest are so; because the contexture of the dupion being stronger than that of the other cocoons, it is consequently less easy to be penetrated by the heat. You must observe to take it from the middle of the basket, because in that part the heat is least perceptible. After you have drawn your baskets from the oven, you must first cover each of them with a woollen blanket or rug, leaving the wrapper behind, and then you pile them above one another. If your baking has succeeded, your woollen cover will be all over wet with a kind of dew, the thickness of your little finger. If there be less, it is a sign your cocoons have been too much or too little baked. If too much baked, the worm, being over-dried, cannot transpire a humour he no longer contains, and your cocoon is then burnt. If not enough baked, the worm has not been sufficiently penetrated by the heat to dilute the liquor he contains, and in that case is not dead.
You must let your baskets stand thus covered five or six hours if possible, in order to keep in the heat, as this makes an end of stifling those worms which might have avoided the first impression of the fire. You are like-
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**Sufficient for three), round my fore-finger, and to give it a twist at the bottom; which is done with the utmost expedition, and gives no occasion for the use of pins. These rolled paper-cakes being likewise of a form more nearly resembling that of a cocoon, with a much narrower opening on the top than the others, takes away the necessity of wasting much silk in the outer web, and consequently leaves more to be employed in forming the ball. The silk is readily taken out of these cakes by untwisting the bottom; and if this be done with moderate care, and the papers are preserved, they will serve several times for the like purpose."
Others advise, that when the silk worms are preparing to spin, little bushes of heath, broom, or twigs, should be stuck upright near the felt or box in which they are inclosed: the worms mount these, and attach their web to them.
When the worms are ready to mount, in order to spin, if the weather be hot, attended with thunder, you will see them in a languishing condition; your care must then be to revive them, which is effected thus: Take a few eggs and onions, and fry them in a pan with some stale hog's lard, the ranker the better, and make pancake; which done, carry it smoking hot into the room where they are kept, and go round the chamber with it. You will be surprised to see how the smell revives them, excites those to eat who have not done feeding, and makes the others that are ready to spin climb up the twigs.
In about ten or twelve days, according to the accounts which we have received from Mr Andrew Wright of Paisley, it may be safely concluded, that if the worms have finished their work, the cocoons may be collected.
We shall now differ with the cocoons from one another according to their value or their use, and consider the method of managing each. They may be distinguished into the good and bad. The good cocoons may be known by these marks: they are little, strong, and firm; have a fine grain, both ends are round, and they are free from spots. Among the good cocoons also may be arranged those which are called culled cocoons, in which the worm, in consequence of sickness, is petrified or reduced to a fine powder. These cocoons produce more silk than others, and are sold in Piedmont at half as much again. They may be distinguished by the nozzle which the worm makes when the cocoon is shaken. Of the bad cocoons there are six species: 1. The pointed cocoons, one extremity of which ends in a point; the silk which covers the point is weak, and soon breaks or tears. 2. The cocoonets, which are bigger, but the contexture is weak. 3. The dupions, or double cocoons, which have been formed by the joint labour of two and sometimes of three worms. 4. The soufflons, which have a loose contexture, sometimes so loose that they are transparent. 5. The perforated cocoons, which have a hole at one end. 6. The bad chouquettes, which is composed of defective cocoons, spotted or rotten. Besides these there is the good chouquette, which does not properly belong to either of these two classes: it is formed of those cocoons in which the worm dies before the silk is brought to perfection. The worms adhere to one side of the cocoon, and therefore when the cocoon is shaken will not rattle: the silk is as fine, but is not of so bright a colour, nor is so strong and nervous, as that which is obtained from good cocoons.
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**Trans. of the American Phil. Soc., vol. ii.**
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**Diff. kinds of cocoons.** wife to take great care to let your cocoons stand in the oven the time that is necessary; for if they do not stand long enough, your worms are only stunned for a time and will afterwards be revived. If, on the other hand, you leave them too long in the oven, you burn them: many instances of these two cases are frequently to be met with. It is a good sign when you see some of the butterflies spring out from the cocoons which have been baked, because you may be certain they are not burnt. For if you would kill them all to the last worm, you would burn many cocoons which might be more exposed to the heat than that particular worm.
The next operation is the winding of the silk. Before you begin to wind, you must prepare your cocoons as follows:
1. In stripping them of that waste silk that surrounds them, and which served to fasten them to the twigs. This burr is proper to fluff quilts, or other such uses; you may likewise spin it to make stockings, but they will be coarse and ordinary.
2. You must sort your cocoons, separating them into different classes in order to wind them apart. These classes are, the good white cocoons; the good cocoons of all the other colours; the dupions; the coccalons, among which are included the weak cocoons; the good choquette; and, lastly, the bad choquette. In sorting the cocoons, you will always find some perforated cocoons amongst them, whose worm is already born; those you must set apart for fleuret. You will likewise find some foulflons, but very few; for which reason you may put them among the bad choquette, and they run up into waste.
The good cocoons, as well white as yellow, are the easiest to wind; those which require the greatest care and pains are the coccalons; you must wind them in cooler water than the others, and if you take care to give them to a good windster, you will have as good silk from them as the rest. You must likewise have careful windsters for the dupions and choquettes. These two species require hotter water than the common cocoons.
The good cocoons are to be wound in the following manner: First, choose an open convenient place for your filature, the longer the better, if you intend to have many furnaces and coppers. The building should be high and open on one side, and walled on the other, as well to screen you from the cold winds and receive the sun, as to give a free passage to the steam of your basins or coppers.
These coppers or basins are to be disposed (when the building will admit of it) in a row on each side of the filature, as being the most convenient method of placing them, for by that means in walking up and down you see what every one is about. And these basins should be two and two together, with a chimney between every couple.
Having prepared your reels (which are turned by hands, and require a quick eye), and your fire being a light one under every basin, your windster must stay till the water is as hot as it can be without boiling. When everything is ready, you throw into your basins two or three handfuls of cocoons, which you gently brush over with a whisk about six inches long, cut stumpy like a broom worn out: by these means the threads of the cocoons stick to the whisk. You must disengage these threads from the whisk, and purge them by drawing these ends with your fingers till they come off entirely clean. This operation is called la Battue.
When the threads are quite clear, you must pass four of them (if you will wind fine silk) through each of the holes in a thin iron bar that is placed horizontally at the edge of your basin; afterwards you twist the two ends (which consist of four cocoons each) twenty or twenty-five times, that the four ends in each thread may the better join together in crossing each other, and that your silk may be plump, which otherwise would be flat.
Your windster must always have a bowl of cold water by her, to dip her fingers in, and to sprinkle very often the said bar, that the heat may not burn the thread.
Your threads, when thus twisted, go upon two iron hooks called rampins, which are placed higher, and from thence they go upon the reel. At one end of the axis of the reel is a cog-wheel, which catching in the teeth of the post-rampin, moves it from the right to the left, and consequently the thread that is upon it; so that your silk is wound on the reel crossways, and your threads form two hanks of about four fingers broad.
As often as the cocoons you wind are done, or break or diminish only, you must join fresh ones to keep up the number requisite, or the proportion; because, as the cocoons wind off, the thread being finer, you must join two cocoons half wound to replace a new one: Thus you may wind three new ones and two half wound, and your silk is from four to five cocoons.
When you would join a fresh thread, you must lay one end on your finger, which you throw lightly on the other threads that are winding, and it joins them immediately, and continues to go up with the rest. You must not wind off your cocoons too bare or to the last, because when they are near at an end, the bairre, that is, the hulk, joins in with the other threads, and makes the silk foul and gouty.
When you have finished your first parcel, you must clean your basins, taking out all the stripped worms, as well as the cocoons, on which there is a little silk, which you first open and take out the worm, and then throw them into a basket by you, into which you likewise cast the loose silk that comes off in making the battue.
You then proceed as before with other two or three handfuls of cocoons; you make a new battue; you purge them, and continue to wind the same number of cocoons or their equivalent, and so to the end.
As was already mentioned, the windster must always have a bowl of cold water by her, to sprinkle the bar, to cool her fingers every time she dips them in the hot water, and to pour into her basin when necessary, that is, when her water begins to boil. You must be very careful to twist your threads a sufficient number of times, about 25, otherwise your silk remains flat, instead of being round and full; besides, when the silk is not well crossed, it never can be clean, because a gout or nub that comes from a cocoon will pass through a small number of these twists, though a greater will flop it. Your thread then breaks, and you pass what foulness there may be in the middle of your reel between between the two hanks, which serves for a head-band to tie them.
You must observe that your water be just in a proper degree of heat. When it is too hot, the thread is dead, and has no body; when it is too cold, the ends which form the thread do not join well, and form a harsh ill-qualified silk.
You must change the water in your bath four times a day for your dupions and choquette, and twice only for good cocoons when you wind fine silk; but if you wind coarse silk, it is necessary to change it three or four times. For if you were not to change the water, the silk would not be so bright and glossy, because the worm contained in the cocoon foul it very considerably. You must endeavour as much as possible to wind with clear water, for if there are too many worms in it, your silk is covered with a kind of dust which attracts the moth, and destroys your silk.
You may wind your silk of what size you please, from one cocoon to 1000; but it is difficult to wind more than 30 in a thread. The nicety, and that in which consists the greatest difficulty, is to wind even; because as the cocoon winds off, the end is finer, and you must then join other cocoons to keep up the same size. This difficulty of keeping the silk always even is so great, that (excepting a thread of two cocoons, which we call such) we do not say a silk of three, of four, or of six cocoons; but a silk of three to four, of four to five, of five to seven cocoons. If you proceed to a coarser silk, you cannot calculate so nicely as to one cocoon more or less. We say, for example, from 12 to 15, from 15 to 25, and so on.
What number of worms are necessary to produce a certain quantity of silk has not been ascertained. And as different persons who wished to determine this point have had different results, the truth seems to be, that from various circumstances the same number of worms may produce more silk at one time than at another. It is related in the second volume of the Transactions of the Society for encouraging Arts, &c., that Miss Williams obtained nearly an ounce and a half of silk from 242 cocoons. Mr Swayne from 50 cocoons procured 100 grains. Miss Rhodes obtained from 250 of the largest cocoons, three quarters of an ounce and a dram.
From a paper in the second volume of the American Transactions, which we have before referred to in the course of this article, we are informed that 150 ounces of good cocoons yield about 11 ounces of silk from five to six cocoons; if you wind coarser, something more. But what appears astonishing, Mr Salvatore Bertezzi, an Italian, to whom the Society for encouraging Arts, &c., adjudged their gold medal, raised five pounds of excellent silk from 12,000 worms.
The cocoons produce a thread of very unequal length; you may meet with some that yield 1200 ells, whilst others will scarcely afford 200 ells. In general, you may calculate the production of a cocoon from 500 to 600 ells in length.
As there is every reason to hope that the silk manufacture will soon be carried on with ardour in this country, and to a great extent, we are happy to learn that the silk-loom has been much improved lately by Mr Sholl of Bethnal-Green. It appears from the evidence of several gentlemen conversant in that branch of silk weaving to which this loom is particularly adapted, that the advantages of this construction are, the gaining light, a power of shortening the porry occasionally, so as to suit any kind of work, being more portable, and having the gibbet firmly fixed, together with the diminution of price; which, compared with the old loom, is as five pounds, the price of a loom on the old construction, to three pounds ten shillings, the price of one of those contrived by Mr Sholl; and that, as the proportion of light work is to strong work as nine to one, this sort of loom promises to be of very considerable advantage, particularly in making modes, or other black work.
As a plate of this loom, with proper references, will render its advantages most intelligible, we shall subjoin it:
Plate CCLXVI. A, A, The fills; B, B, The breast-rolls; C, C, The cut tree; D, D, The uprights; E, E, The burdows; F, F, The battens; G, G, The reeds; H, H, The harnesses; I, I, The breast-roll; K, K, The cheeke; L, L, The gibbet; M, M, The tredles; N, N, The tumblers; O, O, Short counter-meshes; P, P, Long counter-meshes; Q, Q, The porry; R, R, Cane roll pots; S, S, The cane-roll; T, T, The weight bar and weight; U, U, Counter-weights; W, W, The breaking rod; X, X, Cross rods.