At the commencement of the last century a method was discovered in France by Monsieur Bon, of procuring silk from spiders’ bags, and its use was attempted in the manufacture of several articles. Mr. Bon has, however, noticed only two kinds of silk-making spiders, and these he has distinguished from each other as having either long or short legs, the last variety producing the finest quality of raw silk. According to this ingenious observer, the silk formed by these insects is equally beautiful, strong, and glossy with that formed by the silk-worm. When first formed, the color of these spiders’ bags is gray, but, by exposure to the air, they soon acquire a blackish hue. Other spider bags might probably be found of different colors, and affording silk of better quality, but their scarcity would render any experiment with them difficult of accomplishment; for which reason M. Bon confined his attention to the bags of the common sort of the short-legged kind.
These always form their bags in some place sheltered from the wind and rain, such as the hollow trunks of trees, the corners of windows or vaults, or under the eaves of houses. A quantity of the bags was collected from which a new kind of silk was made, said to be in no respect inferior to the produce of the silk-worm. It took readily all kinds of dyes, and might have been wrought into any description of silken fabric. Mr. Bon had stockings and gloves made from it, some of which he presented to the Royal Academy of Paris, and others he transmitted to the Royal Society of London.
This silk was prepared in the following manner:—Twelve or thirteen ounces of the bags were beaten with a stick, until they became entirely freed from dust. They were next washed in warm water, which was continually changed, until it no longer became clouded or discolored by the bags under process. After this they were steeped in a large quantity of water wherein soap, saltpetre, and gum-arabic had been dissolved. The whole was then gently boiled during three hours, after which the bags were rinsed in clear warm water to discharge the soap. They were finally set out to dry, previous to the operation of carding, which was then performed with cards differing from those usually employed with silk, being much finer. By these means silk of a peculiar ash color was obtained, which was spun without difficulty. Mr. Bon affirmed that the thread was both stronger and finer than common silk, and that therefore fabrics similar to those made with the latter material might be manufactured from this, there being no reason for doubting that it would stand any trials of the loom, after having undergone those of the stocking frame.
The only obstacle, therefore, which appeared to prevent the establishing of any considerable manufacture from these spider bags was the difficulty of obtaining them in sufficient abundance. Mr. Bon fancied that this objection could soon be overcome, and that the art of domesticating and rearing spiders, as practised with silk-worms, was to be attained. Carried away by the enthusiasm of one who, having made a discovery, pursues it with ardor undismayed by difficulties, he met every objection by comparisons, which perhaps were not wholly and strictly founded on fact. Contrasted with the spider, and to favor his arguments, the silk-worm in his hands made a very despicable figure. He affirmed that the female spider produces 600 or 700 eggs; while of the 100, to which number he limited the silk-worm, not more than one-half were reared to produce balls. That the spiders hatched spontaneously, without any care, in the months of August and September; that the old spiders dying soon after they have laid their eggs, the young ones live for ten or twelve months without food, and continue in their bags without growing, until the hot weather, by putting their viscid juices in motion, induces them to come forth, spin, and run about in search of food.
Mr. Bon’s spider establishment, was managed in the following manner:—having ordered all the short-legged spiders which could be collected by persons employed for the purpose, to be brought to him, he inclosed them in paper coffins and pots; these were covered with papers, which, as well as the coffins, were pricked over their surface with pin-holes to admit air to the prisoners. The insects were duly fed with flies, and after some time it was found on inspection that the greater part of them had formed their bags. This advocate for the rearing of spiders contended that spiders’ bags afforded much more silk in proportion to their weight than those of the silk-worm; in proof of which he observed, that thirteen ounces yield nearly four ounces of pure silk, two ounces of which were sufficient to make a pair of stockings; whereas stockings made of common silk were said by him to weigh seven or eight ounces.
It was objected by some of Mr. Bon’s contemporaries, that spiders were venomous; and this is so far true that a bite from some of the species is very painful, producing as much swelling as the smart sting of a nettle. Mr. Bon, however, asserted that he was several times bitten, without experiencing any inconvenience; if so, he was more fortunate or less sensitive than any of the spider-tamers with whom we have been acquainted. It was further asserted, that this venom extended itself to the silk which the spider produced; but this assertion was utterly absurd, as any one who has ever applied a cobweb to stop the bleeding from a cut ought to have known. Mr. Bon declared with perfect truth, that the silk, so far from being pernicious, was useful in staunching and healing wounds, its natural gluten acting as a kind of balsam.
The honest enthusiasm of the projector, and the singularity of a regular establishment being formed for rearing and working spiders, excited a considerable share of public attention. It was, indeed, an age of strange speculations, for nearly at the same time a German gentleman broached a scheme for turning tame squirrels and mice to account in spinning; and companies were formed in England, with large nominal capitals to carry out schemes still more preposterous. So important did Mr. Bon’s project appear to the French Academy, that they deputed the eminent naturalist, M. Réaumur, to investigate the merits of this new silk-filament.
After a long and patient examination M. Réaumur stated the following objections to Mr. Bon’s plan for raising spider-silk, which have ever since been regarded as insurmountable.
1. The natural fierceness of spiders renders them unfit to be bred together. On distributing four or five thousand of these insects into cells or companies of from fifty to one or two hundred, it was found that the larger spiders quickly killed and ate the smaller, so that in a short space of time the cells were depopulated, scarcely more than one or two being found in each cell.
2. The silk of the spider is inferior to that of the silk-worm both in lustre and strength; and produces less material in proportion, than can be made available for the purposes of the manufacture. The filament of the spider’s-bag can support a weight of only thirty-six grains, while that of the silk-worm will sustain a weight of one hundred and fifty grains. Thus four or five threads of the spider must be brought together to equal one thread of the silk-worm, and as it is impossible that these should be applied so accurately over each other as not to leave little vacant spaces between them, the light is not equally reflected, and the lustre of the material is consequently inferior to that in which a solid thread is used.