SILK-WORM

SILK-WORM. Although the article now known to our-
selves under the name of silk is "familiar as household
words," yet its nature and origin were but obscurely, if at
all ascertained in ancient times. Pliny, whose judgment
and discrimination as a compiler are not greatly to be re-
lied upon, reports that the bombyx (or silk-worm) is a na-
tive of Kos, an island of the Mediterranean archipelago.
It is known that silk was manufactured there at a very
early period, but Aristotle had previously explained that
bombyxia, or the stuff produced from the bombyx,
was respun and rewoven by the women of that island. The
inventress of this process was Pamphilia. "She unwove
the precious material to recompose it in her loom into
fabrics of a more extended texture; thus converting the
substantial silks of the Seres into thin transparent gauze,
obtaining in measure what was lost in substance. Attempts
have been made to rob the inventress of all the merit be-
longing to this process, by identifying the bombyxia with
the raw material, which it is said Pamphilia and her nymphs
procured from Seres, and spun or wove into sericum or
silk. But the fact of the re-weaving rests upon too good
authority to be doubted."

Had Pliny been right in supposing that silk was a na-
tural product of the island in question, it is by no means
probable that so laborious a process as that of converting
foreign wrought articles into threads for reweaving, would
have been resorted to. Indeed, the Byzantine historians
inform us, that prior to silk-worms being imported into
Constantinople in the sixth century, no one in that capital
knew that silk was the produce of a caterpillar. Although
Aristotle gives an account of the silk-worm, which he de-
scribes as a horned caterpillar, he does not indicate its na-
tive country. Assyria is named by Pliny as the original
region of the bombyx, and he adds the extraordinary state-
ment, that the stuff which the women of Rome unraveled
and wove anew, was made from a woollen substance combed
by the Seres from the leaves of trees, and that draperies
formed from it were imported from the country of the
Seres. These ancient people, we need scarcely remark,
are generally believed to be the same with those we now
name Chinese. Silk, in their language, is called se or ser,
the latter term corresponding with that used by the Greeks,
who, we cannot doubt, derived both the material itself, and
the name by which it was designated, from the Chinese
nation. According to Latreille, the city of Turfan, in
Little Bucharia, was for a long time the rendezvous of the
western caravans, and the chief entrepôt of the Chinese
silks. It was the metropolis of the Seres of Upper Asia,
or of the Serica of Ptolemy, situate, according to that au-

thor, between the Ganges and the Eastern Ocean. Hence the Serica vestis of the Romans, and the word Sericum, their name for silk. The most ancient languages in India have names for "silk-worms," and for "wrought-silk." Ancient Hindu books mention, as separate classes, "silk-worm-feeders," and "reelers of silk." Heavy silks from China, India, and Persia, were unraveled and rewoven, of lighter texture, at Gaza: thence called "La Gaze"—gauze. Fig. 23 represents an ancient Indian reel.

The growth of silk has been considered by the Chinese for 4000 years next in extent and importance to that of rice; and the annual initiatory processes of the hatching eggs of silk-worms, and gathering mulberry-leaves, by the empress, as of the emperor's holding the plough for preparation of the ground in the cultivation of rice, are ordered in the book of rites, printed by Chinese authority, and composed by Confucius 2300 years ago, giving religious ceremonial authority to them. One of their kings was deified because he encouraged the cultivation of the mulberry, and one of their queens on account of her improvements in the art of weaving silks. It is not generally known to European silk-growers, that works have been composed, many ages ago, by the Chinese, describing minutely (and with many particulars not noticed by any one of the nearly fifty French and Italian writers on the subject usually consulted) each process, from sowing the mulberry-seed and hatching the silk-worm's eggs, to the winding of the silk from the cocoon, the doubling and dyeing the filaments, weaving these materials into their truly gorgeous stuffs, and fashioning the latter into garments. Such a volume is now lying before us, published at an astonishingly low price, and illustrated by wood-cuts facing every page. Fig. 24

is an ancient Chinese reel. M. Julien published, about twenty-five years ago, a translation, made by himself, of a valuable work found by him in the Imperial Library at Paris, accurately describing the Chinese method of managing their annual silk-worms, and in producing their best raw silk. This treatise insists much upon the necessity of pure air and wholesome food for the worm, and sug-

gests many important points for improvement on the part of European unprejudiced silk-growers.¹ Nevertheless, while the strength and colour of China silks are in the main still unrivalled, the unevenness arising from the defects in their reeling is no small deterioration of their value, in comparison with the best silks of France and Italy. It is probable that, for a long time to come, we shall have to resort to China for fresh supplies of silk-worms' eggs, when, from epidemic disease, those hatched from acclimated worms cannot be depended upon. About fifty years ago, the eggs of the Chinese white species were successfully introduced into the department du Gard, France, and from them silk of double value in the market has been ever since obtained.

This substance was but slightly known in Europe before the time of Augustus, and in the days of Aurelian was valued at its weight in gold. This was probably owing to the mode in which it was procured by the merchants of Alexandria, who had no direct intercourse with China, the chief country in which the silk-worm was then reared. Though so highly lauded both by Greek and Roman writers, it was in frequent use for many centuries before any certain knowledge was obtained either of the country from which the material was derived, or of the means by which it was produced. By some it was supposed to be a fine down adhering to the leaves of trees and flowers; by others it was regarded as a delicate kind of wool or cotton,² and even those who had some idea of its insect origin, were incorrectly informed of the mode of its formation.³ The court of the Greek emperors, which surpassed even that of the Asiatic sovereigns in splendour and magnificence, became profuse in its display of this lustrous ornament; but as the Persians, from the advantages which their local situation gave them over the merchants from the Arabian Gulf, were enabled to supplant them in all those markets of India to which silk was brought by sea from the East, and had it in their power to cut off the caravans which travelled over land to China through their northern provinces, Constantinople thus became dependent on a rival power for an article now deemed essential to the enjoyment of civilized life. The Persians, with the rapacity inseparable from the power of monopolists, exorbitantly raised its price. Procopius says the price per ounce for silk of common colours was equal to L. 2, 12s., and of royal purple, L. 9, 8s. English money; and many attempts were made by Justinian to free his subjects from their exactions. An accidental circumstance is said to have accomplished what the wisdom of the great legislator was unable to achieve. Two Persian monks, who had been employed as missionaries in one of the Christian churches established in India, had penetrated to the country of the Seres, that is, to China, where they observed the operations of the silk-worm, and acquired a knowledge of the art of working up its produce into so many rich and costly fabrics. The love of lucre, mingled, it is said, with a feeling of indignation that so valuable a branch of commerce should be enjoyed by unbelieving nations, induced them to repair to Constantinople, where they explained to the emperor the true origin of silk, and the various modes by which it was prepared and manufactured. Encouraged by the most liberal promises, they undertook to transport a sufficient supply of these extraordinary worms to Constantinople, which they effected by conveying the eggs of the parent moth in the interior of a hollow cane. They were hatched, it is alleged, by the heat of a dunghill, and the larvae were fed with the leaves of wild mulberry. They worked, underwent their accustomed metamorphoses, multiplied their kind,

Silk-worm, and in the course of time have become almost universally cultivated throughout the southern countries of Europe, thus effecting an important change in the commercial relations which had so long existed between our continent and the east.¹

The cultivation of the silk-worm spread, at the period of the first crusades, from the Morea into Sicily, the kingdom of Naples, and several centuries afterwards, more especially under the administration of Sully, into France, to which kingdom it is now a source of great wealth. It is indeed curious to consider how the breeding of a few millions of small caterpillars should occasion such a disparity in the circumstances, or at least in the outward show, of different tribes of the human race. When the wife and empress of Aurelian was refused a garment of silk on account of its extreme costliness, the most ordinary classes of the Chinese were, we doubt not, clad in that material from top to toe; and although, among ourselves, weekday and holiday, we see the great mass of our female population clothed externally in silk attire, yet our James the Sixth was forced to borrow a pair of silken hose from the Earl of Mar, that his state and bearing might be more effective in the presence of the ambassador of England, "for ye would not," said the uncouth pedant, "that your king should appear as a scrub before strangers." Queen Elizabeth, in the third year of her reign (1560), was highly gratified by receiving from her silk-woman, Mrs Montague, a pair of knit black-silk stockings, with which she is said to have been so delighted as never afterwards to have worn those of cloth. Even Henry the Eighth, notwithstanding his expensive magnificence, could not indulge himself as did his daughter, but wore cloth hose, except on gala days, for which he sometimes contrived to obtain a pair or two of silken ones from Spain.

It was long supposed that the cultivation of the white mulberry required a high temperature, but the contrary is proved by the fact of its thriving well in so many northern provinces of Germany. Even in Russia it is reared with considerable success. In France, however, it is not raised in large quantities with a view to the feeding of silk-worms, except in the central and southern provinces, as far north as the environs of Lyons. It might be easily grown throughout France, as also silk produced. A double crop might be obtained in the south, as in Naples. The white mulberry is by no means nice in regard to the constituent character of its soil, and it is known to flourish in a great variety of situations. At the same time, the nature both of soil and situation seems to exercise considerable influence over the produce of the caterpillars which feed upon its leaves; the silk being cleaner, ampler, and more resistant, in proportion as the plant is successfully cultivated in a dry and rather elevated position. In the south of France it is customary to cut off all the medium-sized branches every year, with a view to facilitate the production of a greater number of young shoots, these bearing the largest and most numerous leaves. The leaves of the black mulberry (Morus nigra), and in general those of all the other species of the genus, are adapted to the nourishment of the silk-worm cultivated in Europe, which is the same as that which produces the greater proportion of the Chinese manufacture. But in Bengal and other parts of India, and to a very large amount in China, valuable silk is procured from the cocoons of other species of moth. The first of these is described by Dr Roxburgh under the title of Phalœna paphia, and occurs in such abundance over many parts of Bengal, and the adjoining provinces, as to have afforded to the natives, from time immemorial, an abundant supply

of a very durable and dark-coloured silk, called Tussah, much silk-worm, used by the Brahmins and other sects of Hindoos. The thread is too fine to be reeled off; the cocoon is softened, carded, and spun. Fig. 25 represents Tussah worms and

cocoons. This species, however, cannot be domesticated; so the hill people go into the jungles, and when they perceive the dung of the caterpillars under a tree, they immediately search for them among the branches, and carry off what they require. These they distribute on the Asseen trees (Terminalia alata glabra of Roxb.), and as long as they continue in the caterpillar state, the Pariahs guard them from birds by day and from bats by night. The natural food of this species is the Byer tree of the Hindoos, called Rhamnus junuba by botanists. The Jaroo cocoons are produced from a rare variety of the kind just mentioned. The tussah silk-worm moth appears to be synonymous with Bombyx mylitta of Fabricius, and is figured by Drury.² The curious silk band, hard as leather, by which this worm secures its cocoon on the tree, is seen in fig. 26. Fig. 25, 2, is the Arrindy worm and cocoon. The

Arrindy silk-worms, however, belong to an entirely different species, Phalœna cynitha of the last named author.³ It seems to be peculiar to two districts in the interior of Bengal,

viz., Rumpore and Dinagepore, where it is reared in a domestic state. The food of this kind of silk-worm consists entirely of the leaves of the common Ricinus, or Palma Christi, which the natives call Arrindy, and hence the name by which the insect is itself distinguished. The cocoons in general are about a couple of inches in length, three inches in circumference, and pointed at both ends. They are of a white or yellowish colour, and their texture is extremely soft and delicate. The filament, indeed, is so extremely

Silk-worm. fine, that the silk cannot be wound off, but must be spun like cotton. The yarn is wove into a kind of coarse white cloth, of a seemingly loose texture, but of such extreme durability, that the life of one person seldom suffices to wear out a garment of it, so that the same piece frequently descends from parent to child. It must always be washed in cold water.¹ Fig. 27 shows the four principal wild silk

by a natural viscosity. The period of hatching may be hastened or retarded by a higher or lower temperature, and the chief point for the breeder to bear in mind is, that the worms should not make their appearance till an abundance of natural food is near at hand. The eggs are at first of a very pale hue, but such as are to produce worms speedily become of a bluish grey colour; the unproductive ones continuing of a pale yellow. As there are tricks in all trades, the foreign dealers often favour their old useless eggs with a wash in dark-coloured muddy wine, which gives them for a time a deceptive healthy aspect. A stove-room, or other apartment, with a temperature of 64° will suffice for the hatching of eggs, and the heat may afterwards be raised with advantage a few degrees every other day, for about ten days, but not so as to exceed about 80°. They will, however, thrive well enough in summer in any comfortably kept apartment, though a continuous warmth by night as well as by day is of great advantage. Whatever parts of a brood are hatched at the same period should be kept together; and those of

moths of India: 1. Tusseh; 2. Arrindy male; 3. Female; 4. Religiosa; 5. Moogha. All these are so easily reared in India, and at so low a cost, as to be used there in immense quantities, and might be imported into Europe with great advantage. The Chinese have wild worms, feeding on the oak, the ash, the pepper tree, and probably other kinds; one produces cocoons monthly, others three-monthly, others one crop a-year.

The silk-worm represented in fig. 28 is found at the roots

of trees in Australia. These caterpillars often become (as those received are) entirely lignified, and from the mouth of each proceeds a root (apparently) of 6 or 8 inches in length.

The practice of rearing silk-worms in this country is usually followed rather as an amusing occupation than for purposes of gain. Abroad, it is pursued with skill and energy as one of the most profitable businesses of life. The female moth is induced to lay her eggs, about 300 in number, upon sheets of paper, to which they adhere

same age, or which shed their skins at same time, ought to be kept and fed together, so that they may pass through the changes of their course with proper care and safety.

The best and simplest apparatus for keeping silk-worms is that used in France and Italy. It consists of small tables to be used from hatching to the time when, by reason of increasing size of the worm, more extensive accommodation is necessary. To meet this, wooden stages about 6 feet wide, and the length which will allow of passing round them, are placed, the lowest one, 3 feet from the ground, then another and another, &c., above it at intervals of 12 or 15 inches. The insects are gradually spread over these till their full size is attained, when, for each ounce of eggs hatched, 300 square feet of boarding superficies must be allowed. When cleansed, it is by turning up the leaves and sweeping off the offal. The worms having six claw-feet and eight that stick by pressure, will not easily fall off the boards. The worm, 1; its head, 2; feet, 3 3; and silk-bags, 4 4, are shown in fig. 29.

Silk-worms ought to be fed with regularity at least four times a day; additional or intermediate meals being given when their extraordinary appetite is manifested. The duration of the lives of these animals depends, to a certain extent, upon temperature and locality; warmth, well kept quarters, and abundance of food, being found to hasten the spinning process. All these things should be very sedulously attended to by those who rear silk-worms in large quantities with a view to profit, time being so important an element in all commercial undertakings.

In the south of France 40 days is the average time elapsing from hatching to beginning to spin the cocoon. Dandolo got the time reduced in his experiments to 30 days; Bronski to 22, 23, and 24 days. The Chinese get to the commencement of cocoon spinning in 24 days. In the United States the best kind of cocoons feed 20 days, the worst 50 days. In England worms hatched from foreign eggs were 56 days before spinning. Others have been 45 days in one case, 70 days in another. Experience can alone decide how far food and warmth may be safely supplied so as to lessen the time.

When the silk-worm makes its first appearance, it is of a dark colour, and measures only one or two lines in length; after the lapse of eight days, it is attacked by a lethargic sickness. The creature is about to cast its skin, and for about three days it remains motionless, refusing food. On the termination of this period the old skin opens at the anterior end, the fore-legs are disengaged, and the new and delicately attired worm escapes forth, to enjoy itself once more on pastures green. It had previously exuded a peculiar fluid, and had also, by means of its silken string (how provident is benign nature!) fastened down its old and useless coat, that it might not be dragged after it when the hour of delivery has arrived. This coating is so complete, that even the skin which covers the eyes, and the teeth are thrown away. Immediately after this renewal, the body of the worm appears grey and somewhat wrinkled, the new coat being made full size to admit of future growth; but the latter attribute speedily disappears. It feeds freely for five additional days, during which it grows to about half an inch in length, and is then seized by its second sickness, and again casts its skin. Then succeed other five days of feasting, in the course of which it increases to three quarters of an inch, when it sickens a third time, and acquires in a similar manner a third suit. Again five days of feeding; again a removal of the outer garment, or a fourth casting of the skin. The caterpillar now measures from an inch and a half to two inches long, and for a continuous period of about ten days it eats voraciously, and increases greatly both in length and thickness. On the expiry of this last-mentioned period, it has attained the full size of a silk-worm, being from two and a half to three inches long. Its desire for food abates, it nibbles and wastes its leaves, then ceases to eat, and becomes restless and uneasy, moving circularly from side to side, owing to some instinctive feeling of desire to secure a quiet haven in which to spin its silken shroud. Its colour is now of a palish-green, with a mingling of a deeper hue. In the course of about twenty-four hours from the time of its having ceased to feed, the silky fluid becomes abundantly supplied to its interior reservoirs; the green colour disappears; the body becomes of a soft yellow, and somewhat transparent towards the neck. Previous to spinning, the general dimensions rather decrease than otherwise, but greater firmness of substance is acquired.

When the desire to spin is thus unequivocally manifested, art must come in aid of nature. In China, netting is extended on frames. In India, paper tubes are placed; into these caterpillars will creep and weave their golden wool incessantly till the work is done. Those who rear extensively in Europe, supply their caterpillars with small

twigs or branches of broom, heath, or any other brush-wood, which happens to unite suppleness and tenacity. These are placed carefully so as to form arches across the tables, leaving in the arcades room for the worms to adjust themselves comfortably to spin (fig. 30).

Great attention must now be paid in regard to keeping up a moderately warm temperature. The observations of a writer in the fifth volume of the Society for the Encouragement of Arts, amply illustrate this important point. He had successfully reared 30,000 silk-worms, when in the beginning of July, just as they were about to spin, there came a chilly north-east wind, and many assumed the chrysalis state, without making any attempt to form a protecting covering. On examining these individuals, it was apparent that their silken reservoirs had been congealed by cold, so that the insects were unable to draw out the filaments in their usual slender state, their own capacity of movement and exertion being no doubt at the same time chilled. Even when they have commenced to spin, or have made some progress in their labours, they will cease if exposed to damp and cold, and if the surrounding web is still of sufficient transparency, they may be seen lying idle and inactive in the interior of their cocoons. But if the temperature is raised, they will immediately resume their work. A heat from 65° to 70° is thought advisable at this time. The opposite extreme of oppressive heat or close temperature must be equally avoided.

These beautiful silken coverings, or cocoons as they are called, are generally completed in three or four days. They are commenced by the formation of a loose decomposed structure of an oval form, made of what is denominated floss silk. Within this, in the course of the ensuing days, the firmer cocoons are completed. These are rounded somewhat oval balls, varying in tint, but some species give cocoons of a golden hue, some others of a straw-colour, and some white. Those of a bright yellow yield the greater weight of reeled silk, but as the finer colouring substance is contained chiefly in the gum which is boiled out before weaving, less advantage is reaped by the grower. Raw silk, of a pale colour, is moreover preferred, on account of its better reception of certain dyes. Whether the insect sleeps or not during spinning, it rests. Its daily work may, by cutting the cocoon lengthwise, be separated, and the different layers found indicate the rests, and are also distinguished by great difference in the proportions of gum, albumen, and colouring matter found in each. The included worm, having finished its labour, casts its skin once more, but never appears again as a caterpillar, as it now assumes that rounded shapeless form termed chrysalis. The cocoons may be selected for reeling in about a week, and then comes the ungrateful and ungracious task of destroying the peaceful tenants of the tomb. This is variously accomplished, either by exposure (in sunny climates) for some hours to unclouded solar light and heat; by

Silk-worm steam; or by placing the cocoons in a temperature corresponding to that of an oven from which loaves have just been withdrawn after being baked.

If not killed, the chrysalis remains in its natural dormant state for a longer or shorter time, in accordance with the climate in which it has had its birth. In eastern countries this is not more than eleven days; in the most southern parts of Europe from eighteen to twenty; in France about three weeks; in England, if unaided by artificial means, about a month. After these respective periods, according to climate, whether natural or acquired, the perfect moth emerges, and the reason for destroying the chrysalis is this, that, in emerging, the moth makes an opening by softening the gum and putting aside the silk thread, and so by letting in the water prevents the cocoon being reeled. A few, however, are of course spared for the sake of a future progeny, sound cocoons being selected, and in equal numbers as to sex. The worms break out of the egg in due season, go up to spin, and eventually emerge from the cocoon, for the most part, from two to three hours after the morning light reaches them.

Such as have been killed for reeling are, before the commencement of that process, placed in warm water, so that their gummy nature may be partly softened, but not dissolved. The length of silken thread which may be unwound from a single cocoon, is in truth astonishing. Count Dandolo found it occasionally to exceed 600 yards. The French commissioners, examining Count Bronski's cocoons, saw one reeled which they certify to have been 982 metres in length. The length must, to some extent, be indicated by the weight of the cocoon, an Indian one of $1\backslash frac\{1\}\{2\}$ grains, and an American one of 8 grains, may well be supposed to differ greatly in length of thread; more facts are needed to decide on any true average. The only English filature of any magnitude for reeling silk was put into operation at Tiverton in 1825, by J. Heathcoat, Esq., who caused 35,000 lb. of Florentine cocoons to be reeled there. The quality and quantity of raw silk (about 3300 lb.) were satisfactory, and this produce was wrought into lace. There was no profit over silk grown abroad.

The following statements are intended to explain those points which are necessary to the production of the raw silk of commerce of the best quality, and at the least cost. The silk-worm cultivated on the continent of Europe is of the same family as that which produces the white silk we import from China. So far as is at present known, the Chinese cultivate the production of that domesticated annual worm, which gives the pure white silk only, when they wish to use the raw silk reeled from them in the manufacture of their woven, plain, or flowered broad fabrics, crapes, &c. They have, however, other species, some monthly, or rather reproducing eight times; and some three-monthly, or producing four successive hatchings and four crops of cocoons, in the year. Like those of India (with which they are probably identical in origin), these cocoons are all inferior in weight, and, from the greater fineness of filament, much more difficult to reel in an even size of thread; therefore are much less valuable in commerce. These silks, as also those from their wild silk-worms (of which an immense quantity are gathered every year), are spun and woven into the heavy silk cloths with which the Chinese cover themselves in cold weather, and are cheap enough for every common purpose. Those which were brought into Europe originally produce chiefly yellow silk; but about one-tenth of the worms in each yellow hatching give cocoons of a spurious, inferior white colour. This domesticated silk-worm of China, Bengal, or Europe, is the larva of the Bombyx mori, a pale coloured moth, with two or three obscure and transverse streaks, and a lunate spot on the superior wings. This caterpillar feeds on the leaves of the mulberry; and before assuming the chrysalis

form, it spins a protective covering. This cocoon is oval silk-worm. in shape, if by a female; but if by a male, the cocoon is round at each end, but of less circumference in the middle part. The engraving (fig. 31) shows two species, 1, 2, of

Italian worm; the moth, 3; the cocoon of a male, 4; that of a female, 5; and the chrysalis b, with the last skin of the worm, c in the latter. On the cocoon of the male is shown, a a, the zig-zag mode in which the thread of silk is laid in patches by the worm when forming its temporary abode. The finest of each sex in size, weight, colour, and compactness of make, are carefully selected and secured for next year's eggs; any discoloured, or ill-made, are reeled off without killing the chrysalis; the remaining good ones are, in China, killed by being placed in hot dung; in India, under the heat of the sun, or dung, or by baking; in Europe, by baking (or which is best), by placing the cocoons in a steam bath.

Domesticated silk-worms will live, and even a small portion of a hatching may spin cocoons, if fed upon lettuce; but their existence is a weak and languid, because an unnatural one. A healthy, full-grown worm shows, along each ring on its back, from tail to head, an expansion and contraction, indicating pulsation of 40 to 45 beats in a minute. If fed on lettuce, this is reduced to 20 or 25, and often lessens till the insect ceases to live. The mulberry-

leaf, therefore, furnishes its only natural aliment. This in Italy and France is for the most part the produce of the

Silk-worm, white variety (Morus alba). The wild leaf, 1; grafted, 2; black, 3; and large Multicaulis, 4, are shown in fig. 32. The worm is always most safely and easily fed upon the white kind until it has completed its last sloughing of the skin; by that time the black mulberry (Morus nigra) will usually have come into leaf; and will, if the silk to

be produced be of the yellow colour, furnish superior brilliancy in dyeing the darker hues. For white silks, and the lighter shades of dyed colours, no doubt the white, or rose variety of mulberry, should furnish exclusively food for the worms. Valentia silk is, to a large extent, produced by worms fed on black mulberry-leaves. An experiment, by the hatching of about 10,000 worms at Nottingham, in 1839, showed a loss of seven-eighths of the worms which were partly fed on lettuce. Of those fed (by necessity in this case, from the absence of any white mulberry-trees) upon the leaves of the black mulberry, the loss, before spinning of the worms hatched, was between 30 and 40 per cent. The loss in Europe, under peasant manage-

ment (which includes half the production of ordinary years), is generally 40 to 60 per cent., fed upon white mulberry. Larger proprietors suffer less loss from ordinary diseases, often rearing 70 per cent. of the worms hatched. Epidemics are, however, very fatal, when large numbers of worms are bred together.

The mulberry-tree is well described, from its important uses, by a French writer, Olivier des Serres, as "full of the blessing of God." It is found growing in most temperate climates in the Old World, and several varieties in the New. Long before the time of Justinian it had been brought from China or India into Persia and Asia Minor; and, at length, was spread around the Bosphorus, and throughout Greece, probably giving the name Morea to the Peloponnesus. In 1130, Roger King of Sicily transported the tree, together with silk-worms, and persons used to their cultivation, into his own country. It became well known in Naples; from whence, in 1493, certain nobles, who had followed Charles VIII. to Italy, on their return from that unfortunate expedition, brought the mulberry, and planted it at Monteli-

mart; where, a few years since, these trees, the source of so rich a branch of commercial industry to France, were still the objects of almost religious veneration. Our James I., desirous of emulating the successful efforts put forth on the continent to establish the growth of silk, caused black mulberry-trees to be planted in nearly every parish in England, where thousands of them are still flourishing in a fruitful old age. Experiments have frequently been made for raising silk-worms in this country. The few in which French or Italian eggs, and the black mulberry, have been employed, proved successful. Berthezen thus took the medal of the Society of Arts seventy years ago, by producing good cocoons and raw silk, no doubt hatching French eggs, and using the black mulberry-leaf. The attempt, before mentioned, made at Nottingham, was perfectly successful. Specimens of the cocoons are placed in the Adelphi, London, and in museums in Birmingham, Glasgow, Manchester, &c. Three hundred of these cocoons weighed a pound. In France and Italy two hundred and fifty are usually required. The time from hatching to spinning was prolonged about fourteen days by the humidity of our climate. Cocoons spun by the common English silk-worm average, when dry, each 1 to 1½ grains (fig. 33); Bengal

rainy crop (November), 1½ to 2 grains (fig. 34); Italian vary from 3 to 6 grains (fig. 35); Nottingham experiments from foreign eggs, 2½ to 5 grains (fig. 36). In New Jersey, U.S., by two hatchings a-year, cocoons have been obtained from one kind of silk-worm averaging about 5 grains (fig. 37); and from another, an annual worm (Mammoth), weighing, when dry, 6 to 8 grains (fig. 38). Though silk of good quality may be produced in England, yet its cost, as compared with that of drier climates, would render it unprofitable.

The mulberry-tree and the silk-worm thrive best in a pure, dry air, in the neighbourhood of mountains, and in ill districts, upon a dry soil. The tree should be trained

to a standard form, and an open head, being annually pruned, and the stem and principal branches freed from insects. Thus treated, the trees will bear being stripped of the leaves each year, for ages. At thirty years of age an average tree will supply 50 lb. weight of leaves annually, and 250 lb. weight of leaves will feed 2500 worms, equal to the

production of 12 oz. weight of raw silk. The following short particulars of a certain French "recolt" (crop) will show consumption of food, and results:—The manager hatched 11 oz. of eggs; i.e., about 33,000 per oz., or 363,000, reduced gradually before spinning to 241,000. He supplied, during 32 days, up to 30th May, and before

last change of skin, 10,600 lb. weight of leaves. On 31st May, 1000 lb.; June 1, 1500 lb.; 2d, 2500 lb.; 3d, 2500 lb.; 4th, 2500 lb.; 5th, 2000 lb.; 6th, 500 lb.; i.e., during these seven days of their great appetite, and filling silk bags for future cocoons, these insects ate 12,500 lb. weight of leaves; in all, they consumed 23,100 lb. weight of leaves;

1050 lb. weight of cocoons were spun, from which 87½ lb. of raw silk was reeled. To the peasant breeder, the cost of this process is the labour of his family and himself, in planting,

pruning, hatching, gathering leaves, and feeding; and the silk-worm proceeds paid to him for his cocoons in hard cash is usually entirely additional to his ordinary income. The average of many years' cost and prices, computed by a French grower of high character, is, that the proprietor of large crops gains 12½ per cent.; and the purchaser and reeler of cocoons for the market makes about 12½ per cent. upon his outlay in capital, risk, and skill. A rough calculation is thus made in France:—An ounce of eggs requires 20 quintals of leaves, and will bring 1 quintal of cocoons, to be reeled into 120 ounces of silk. The temperature of the air in which silk-worms are bred should be at hatching about 85 deg. Fahr., and gradually lowered to 75 during great appetite, and 65 at spinning, and with adequate means provided for its frequent change. As the insect progresses in age and size, the air without renewal soon becomes vitiated. Cleanliness is imperative necessary to its health; therefore vegetable refuse and excrementitious matter must be withdrawn; at first weekly, then half-weekly, daily, and during the great appetite, constantly. The leaves must be given to it free from moisture, not heated, or even damp, however wet when gathered. If there have been diseases amongst the worms in the previous year, the walls, boards, and tools for cutting off branches, and spreading out leaves, must be most carefully scraped, washed, and purified. We have known disease continue in a building, the wood-work and even walls becoming leprous, and necessitating destruction, or disuse for this purpose, of the place altogether. Late experience for several years of the loss of half or two-thirds of the crop in Europe, by epidemics amongst silk-worms, renders this a most interesting and important point in management. Foreign writers have enumerated as the diseases of silk-worms "Calcinés" and "Lusettes," "Gras" and "Tripes" and "Muscadine";—the two former produced by electrical and atmospheric causes; the next two by improper state or quality of food; the last as an ineradicable plague or leprosy—the cause unknown. Each of the first-named four diseases, if it invades a breed of worms within the last ten days of their eating course, or when going up the twigs for the purpose of spinning their cocoons, is dangerous and difficult to remedy. Lessened supplies of very carefully selected leaves, and plenty of fresh air, into which are introduced the fumes of burned aromatics acting as stimulants, have been, in China and Europe, found most useful. A hatching has been saved, when supposed to be beyond restoration to vigour, and thrown out upon a straw-yard, by the clear cold air of night, and almost every worm has formed its sound cocoon, the crop being, four days after, gathered from the straw. Increased dry temperature, together with vinegar burned in large quantities for an hour or two, has sent up to spin nearly every worm which had, from the first effort to mount, fallen, in consequence of a sudden north-east cold blast, or of a violent storm, and discharges of electricity. We have observed two diseases not described in works on this subject (fig. 40). One

(1), probably the effect of lightning, rendering the head and two front rings of a coal-black colour, and showing a tight ligature beyond; the other (2) swelling out the four middle rings with tight ligatures at each end of these rings. Both were fatal and incurable, as far as could be ascertained. This whole subject of disease amongst silk-worms deserves more minute

Silk-worm. inquiry throughout their whole course on the part of scientific observers. This will necessitate a close analysis of the proportions of fibre, resin, albumen, saccharine, and colouring matter and water, which enter into the composition of the most healthy leaves, and from which the insect obtains nutriment, and ultimately eliminates the silky materials for its cocoon in largest abundance. All these silk-spinning caterpillars can throw out, on the approach of danger, their silk thread from the opening of the tube under their mouth, attaching it at once to anything near; and this they do at any time from the moment of hatching, even before having eaten. The thread is double, supplied from long silk bags, which open into the tube or duct where they are brought together, and are there covered with gum and other matters, which varnish hardens immediately on exposure to the air. This filament of the cocoon is continuous through its whole length; its size is according to the species of caterpillar, and also depends on the health and strength of each worm. It decreases gradually as drawn out within the cocoon, till it becomes at the last end only about two-thirds the size it was at the outside commencement. The eventual thread of raw silk is rendered of even size by its being composed in reeling of two-thirds of the filament drawn from those cocoons which are partially reeled off, and one-third from those newly begun to be drawn off. Though the form of this silk ball is somewhat rounded or oval, yet the insect does not lay its thread in rings round its circumference, but in zig-zag patches here and there; which, nevertheless, when the cocoons are wound off in warm, or even cold water, if the produce of healthy worms, will draw out in a perfectly straight line; and the whole covering of the chrysalis within will be wound off, from end to end (in length usually of 600 to 1000 yards) frequently without breaking. But if the insects have been weak or unhealthy; and if therefore ill supplied with the varnishing, adhesive substances which should make all parts of the entire length of the thread equally compact as laid in the cocoon, and thus equally softened by the warmth of the water, then one or more of these zig-zag patches will often separate in a mass from the remainder of cocoon, and come off, passing towards the reel in a "burr" or knott. This is not all the mischief, which the following explanation shows:—As the raw silk threads are winding off, they bring with them 25 or 30 per cent. of their entire weight in gum. To

out. To accomplish this with ease and exactitude, the silk is generally wound from the basin (fig. 41, at 1) from two sets of cocoons into two separate skeins on the reel; but the thread of one skein is carried ten, fifteen, or twenty turns round the other (at 2), and then again separately carried forwards. This torsion forces out, according to the size of the thread, and number of turns round each other, the surplus quantity of gum. But if one of the burs, above spoken of, arrives at this entwining junction, it inevitably breaks one of the threads, and then the whole of both pass together, in one thread, upon the skein, which there becomes, for so many scores of yards as the reel may draw off before its exceedingly swift revolutions can be stopped, a thread of double size—twelve cocoons instead of (say) the intended six cocoon silk ("un marriage"). This, however careful the reeling, reduces the value of raw silk ten to fifty per cent., and must result where there is an unhealthy state of the worms. The best cocoons may be, from want of skill or carelessness, reeled into uneven silk. Bruttia silk sold in 1825 at 10s. per lb.; care and skill have raised its value to 30s., and even 40s. per lb. in recent years. The pure white three-cocoon silk of the Cevennes is worth 60s. to 70s. per lb., this price being paid chiefly on account of the perfect evenness of so fine a thread. To avoid the evils and loss resulting from double threads in reeling, the thread of each skein may, when the other is broken, be cut by sharp blades (fig. 42), or it may receive the necessary torsion round itself (fig. 43, 1), then the burr breaks it, and no more goes on the reel till tied up afresh. Raw silks may be reeled into threads of heavy weights, say 20 or 40 cocoons each, by a system of division into small numbers, say of four or five cocoons each, at the basin, so as to admit of constant accuracy in keeping up supply to replace broken filaments, and then giving the whole a subsequent union before torsion (croisée) (fig. 43, 2; and fig. 44). The

result will be perfect evenness of thread; and for most useful purposes a saving of all the expense of labour and waste in winding from the fine raw, and doubling to make the thread heavy enough for the loom. This method (discovered by us, and patented in France and Italy in 1825) has become almost universal where the raw silk is used, unboiled, or where heavy "trames" are desired of an even, good quality. Raw silk may be reeled, and receive an actual twist at the same time, while passing upon the bobbin (fig. 45). This also was the subject of a patent in 1825-26; but in practice nothing is gained by it in time or labour, and certain inconveniences appear to be an unavoidable result.—For peasants to reel their own cocoons is an unwise system;

bind the four, six, or more filaments from as many cocoons together in one thread, a certain proportion of this gum must be left with the thread; the remainder is forced

their cocoons, wound off by professed silk-reelers, always produce a much more valuable result in quantity and price. The peasant reeled raw silk of China, India, and every other silk-growing country, mixing, as it more or less does, with "filature" (factory reeled) raw silk, tends to depreciate the character of really first-class productions. Peasant reeling is rapidly going out of use in France and Italy.

It follows, from what has been stated, that, in order to obtain good raw silk, there must be good, well-made cocoons, reeled with care and skill. In order to get such cocoons there must be healthy worms; and to secure these, pure air, dry, wholesome food, and vigilant superintendence, and this not in low and marshy, but in hilly parts, where the mulberry-leaf will, instead of gross watery substance and large size and weight (which may suit the planter but kill the worm), possess a warm

and somewhat exciting flavour and scent. The more worms spin out of a given number hatched, the more silk will be reeled from their cocoons, and the more valuable the product in sale and use.

The silk-worm does not eat a quantity of food proportionate to the size and weight of its cocoon, as compared with others. The worm acclimated in England eats as much as the French, yet the cocoon of the former yields only one-fifth of the weight of silk. The growth of the Bengal silk of commerce supplies a most important example of neglecting this fact. This Indian silk is produced partly by a worm relatching four times a year, viz., two three-monthly, fine weather "bunds" (crops), and two rainy "bunds," and partly by one annual worm; both kinds are fed on mulberry, the Morus Indicus. Three thousand cocoons produce, from French or Italian worms, 16 oz. of raw silk. It requires 14,000 of Indian annual crop, and often 20,000 to 22,000 cocoons of three-monthly crop, to reel into the like weight, and that of far inferior quality and value. The thread of the Bengal silk-worm is so attenuated, that a very large proportion of the cocoons breaks off in reeling, and there may be twenty to thirty required to obtain the required size—a number which any one accustomed to silk-reeling will know

cannot be counted. Six or ten are therefore supplied at once, which render an even thread, and consequent average value in the market, impossible. The remedy at once seems to suggest itself. Resort to China, to America, or to the continent of Europe, for other and better eggs. This was proposed to the East India Directors in 1832. The memorial was forwarded to the council in Bengal, and by Lord W. Bentinck to every filature. A few pounds sterling would have secured eggs for the supply of every silk-growing district in the peninsula; but they were not obtained, and things remained much as before—a fivefold prime cost, and an article of two-thirds the value. The lamented death of the late Dr Royle has alone prevented the special points insisted upon in this paper (as in the memorial referred to) from again reaching India, and strengthened by his scientific researches, so as to give them effect in improving this truly important and wide-spread product of Indian labour. It is a fact not so well known as it ought to be, that there are more people on the face of the globe clad in silk fabrics than in any other textile material whatever. To what extent India might, by this substitution of superior breed of worms, with other improvements, supply Europe and the world with silk, it is difficult to say. The real cost of the silk supplied in 1800 was but 10s. per lb.; all the testimony of experienced civilians, together with that of the Company itself, say it need only cost 7s. per lb. In 1827 it had risen to 13s. per lb., all expenses paid on board. If the annual worm of China or Europe were taken to the hitherto useless millions of mulberry-trees now growing amongst the lower ranges of the Himalayas, the annual crop of cocoons would doubtless surpass in valuable results, by this three months' labour only, all the five crops added together at present obtained, and leave the peasants nine months for other profitable employment. Mr Bashford, of Surdah, East Indies, an eminent silk-grower of long experience, in a paper read to the Society of Arts, February 1857, states that, having imported French and Chinese eggs, he proceeded, through very careful and well-arranged experiments, to obtain cocoons equal to those of either country. But his main object was to improve the native breeds of worms by crossing them with the Chinese and French, and so continue a three-monthly crop. There is no instance known where any other than an annual crop yields good silk. This plan did not succeed. Under the circumstances of excessive heat, and mulberry-trees growing in marshes, deep in water, hatching-houses filthy and without ventilation, and obstructive attendants, the best foreign worms would, and did slowly, but effectually, become extinct. The facts given by Mr Bashford confirm the principle that an annual silk crop should be first obtained of cocoons from foreign eggs; and that the whole system, and even the localities for carrying it on, should be, if needful, changed. The initiatory proceedings and expenses, which need be, for all really useful purposes, of very moderate amount, should be by public authority and at the public charge. Judging from the spirit and talent evidenced in his paper, no man would be more suitable for carrying them out with firmness, skill, and prudence, than Mr Bashford himself.

An effort was made, 1840-1845, to grow mulberry-trees, and produce raw silk, in Jamaica. The hilly parts of the island were found sufficiently temperate for both trees and worms. American eggs were hatched under the care of an experienced grower from the United States, and several small annual crops of excellent cocoons were the result. Silk, of good quality, reeled from them, together with letters from Lord Metcalf, the then public-spirited governor, under whose auspices this attempt was originated, and others, which give details of management, are now lying under our eye. But the affair was in the hands of a public company, who laid out at once too much capital, incurred heavy, yet needless, expenses, and, growing impatient of slow returns, the spe-

culation collapsed, and, it is presumed, a promising and perfectly feasible plan was abandoned. Yet one hundred pounds weight of mulberry-seed, delivered to five hundred negro peasants, having cottages and families amongst the hills, followed three years after by one hundred ounces of good silk-worms' eggs, distributed, in like manner, would have almost certainly resulted in crops of good cocoons. Fifty or sixty basins and reels would have been required to give the raw-silk. The total outlay would not have exceeded £500 sterling. The proverb is true of every effort made successfully to grow this important raw material: "Patience and perseverance turn mulberry-leaves into the silken robes of a queen."

The following books will be found of use on the study of silk:—

Le Tisseur sur l'Education des Vers à Soie, &c., 1744. L'Art de Cultiver les Muriers blancs, d'élever les Vers à Soie; et de tirer les Cocoons, Paris, 1757. Culture des Muriers blancs, et Education des Vers à Soie Pomnier, Orleans, 1763. Mémoires sur l'Education des Vers à Soie

et le Culture des Muriers blancs, l'Abbé des Sauvages, 2 vols., Nismes, 1763. Mémoires sur la manière d'élever Vers à Soie et la Culture des Muriers blancs, M. Thome, Lyon, 1767. Recherches sur les Maladies des Vers à Soie, &c., P. H. Nysten, 1808. Recherches et expériences sur la Culture des Muriers blancs, Calvel, Paris, 1812. Mémoire sur la greffe du Murier, Duvaure, 1818. In volume seventieth of first series, and volumes second and seventh of second series of Annales d'Agriculture Française, interesting papers may be found. Malpighi and Lowenhook have written upon the anatomy and habits of the silk-worm. Vincent St Laurent has given an analysis of Dandolo's celebrated work on the silk-worm. Trattato sopra la Cultura del Gesso, &c., Naples, Belmont di Bolzano, 1795. Under similar titles are works written in French by Bourgeois, Constant Castollat, Isnard, Rogard, de St Jean du Gard, Duhamel, and the Abbé Nollet. In Italian—by Vida, Le Guidoboni, Le Gallo, Le Corsuccio, Garzoni, and Pol Francesco Pol Franceschi. The following French works on Dyeing Silk may be consulted with advantage:—L'Art de la Teinture Soye, Macquer, 1763. Sur les Teintures Solides, ou recueil des Expériences, par Daubourney, Paris, 1778. Éléments de l'Art de la Teinture, Berthollet, 2 vols., 1791. Also the Journals of Arts and Manufactures, published by order of the French Minister of the Interior. (W. F.—N.)