SPIDER-SILK.
It may not be inopportune to recall to the minds of our readers a somewhat neglected silk-source, which may perhaps at some future period form a profitable commercial undertaking. It is unnecessary to expatiate upon the beauty of the gossamer spun by the Aranea diadema, or common Garden spider, as the fairy-like tracery must be familiar to every one who has wandered through the woods in autumn, when the gauzy films festooned between and over the bushes were rendered prominent through saturation with dew or a sprinkling of hoar-frost. The thread produced by this little creature is estimated to be many times finer than the most attenuated filament of the well-known silkworm of Europe, the Bombyx mori; consequently, as may be imagined, the difficulty of obtaining such silk is so great that, except for land-surveying purposes, the web of spiders as a class has not been permanently utilised. For the latter object, the plan adopted by our surveying instrument makers[1] in order to secure small supplies of spider’s line, is remarkably simple, and affords an illustration of how closely instinct in the lower creation sometimes approaches reasoning intelligence in the higher. Having caught the selected spider, it is immediately tossed backwards and forwards from hand to hand of the operator, until the impulse of self-preservation induces the emission of its thread. Meanwhile, a wire, bent double like a hairpin—the distance between the prongs being slightly greater than the diameter of the telescope to be fitted—is at hand to receive the silk. As soon as the filament appears, the end is attached to the wire and the spider dropped, when it immediately emits its thread with great rapidity, in the hope of reaching the ground and escaping. This is frustrated by a dexterous revolution of the extemporised reel, which winds up the line as fast as it is produced, until the spider’s store of silk is exhausted. It is then allowed its liberty; and a touch of gum on each prong secures the silk in convenient lengths for future use.
Rather more than fifty years ago, it seemed as if a new and important trade was about to be inaugurated by the rearing of spiders for their silk, which the Society of Arts marked with their approval by awarding a medal to a Mr Rolt for his success in obtaining an appreciable quantity from the Garden spider. This gentleman accomplished his purpose by connecting a reel with a steam-engine, setting it revolving at the rate of one hundred and fifty feet per minute; when, after two hours’ patience, he wound off eighteen thousand feet of beautiful white line of a metallic lustre from twenty-four spiders. Subsequent examination proved this thread to be only the thirty-thousandth part of an inch in diameter, so that a single pound-weight was estimated to be sufficient to encircle the globe. Although this gentleman appears not to have pushed his interesting experiments much further, a Frenchman of Languedoc afterwards established a factory for producing and weaving spider-silk into articles of utility. He manufactured gloves and stockings which were much admired; but the difficulty of rearing a sufficiently numerous family of spinners within a reasonable space, on account of their extreme pugnacity, soon interfered with this budding industry, and led to its abandonment. No difficulty was experienced by M. Reaumur in collecting some five thousand spiders and immuring them in fifty separate cells; but unfortunately, on one occasion there occurred a scarcity of flies; a food-panic ensued, and the hungry and infuriated prisoners, escaping during the night, fell upon one another with such deadly ferocity, that when the anxious proprietor paid his usual morning visit, only a few gorged and bloated specimens survived. It seemed, indeed, so vain to expect European spiders to exist peacefully within sight and reach of each other without their usual employment conducted after their own fashion, that the hope of rendering them useful for commercial purposes gradually died away, and has for many years been almost wholly relinquished.
Certain species of foreign spiders, however, when examined with a view to their silk, offer a field of very considerable encouragement. In the island of Ceylon there is one described by Sir Samuel Baker as being two inches long, with a large yellow spot upon its back, which spins a beautiful yellow web two and a half feet in diameter, so strong that an ordinary walking-stick thrown in is entangled, and retained among the meshes. As might be expected, the filament, which is said to exhibit a more silky appearance than common spider’s web, is easily wound by hand on a card, without any special care being exercised in the operation. A spider of even more formidable dimensions is alluded to in the fascinating work, The Gardens of the Sun, by Mr F. W. Burbidge. It is a large, black, yellow-spotted creature, measuring six or eight inches across its extended legs, and it spins a web strained on lines as stout as fine sewing-cotton.
The prince of the species, however, seems to be the Aranea maculata of Brazil, vouched for by Dr Walsh as having been seen and examined by him during his travels in that country. In this huge, ungainly, yet harmless and domesticated creature, we evidently possess a treasure of a silk-spinner, with which the non-nervous and practical among our colonial ladies, situated in moderately warm localities like Northern New Zealand, Queensland, and the Cape of Good Hope, might spend many a profitable hour when they became mutually acquainted. It is not only free from the vices of the European spider in not devouring its kind, but it actually exists in little harmonious communities of over one hundred individuals of different ages and sizes occupying the same web. Like the last-mentioned spider, this one is of similar colossal dimensions, and it spins a beautiful yellow network ten or twelve feet in diameter quite as strong as the silk of commerce. Regarding the toughness of this filament, the doctor says: ‘In passing through an opening between some trees, I felt my head entangled in some obstruction, and on withdrawing it, my light straw-hat remained behind. When I looked up, I saw it suspended in the air, entangled in the meshes of an immense cobweb, which was drawn like a veil of thick gauze across the opening, and was expanded from branch to branch of the opposite trees as large as a sheet, ten or twelve feet in diameter.’ Another traveller, Lieutenant Herndon of the United States navy, confirms Dr Walsh’s account of this enormous spider, with the addition that he saw a single web which nearly covered a lemon tree; and he estimated its diameter at ten yards!
Probably the latest addition to our knowledge of spider-silk has recently come from the Paris ‘Ecole pratique d’Acclimation,’ a member of which has discovered an African species which spins a strong yellow web, so like the product of the silkworm as to be scarcely distinguishable from it. So promising a material as a fibre of commerce does this seem to be, that, after close investigation, a syndicate of Lyons silk-merchants has reported in its favour; the more so as there is said to be no difficulty in acclimatising the spider in France.
In those gigantic spiders there is evidently the nucleus of an important industry of the future, which colonists might perhaps easily ingraft upon their ordinary sericultural or other occupations. If the period has scarcely yet arrived for the profitable utilisation of ordinary spider’s web, surely something might be evolved from the less attenuated filaments just alluded to, which are strong enough to whisk a man’s hat from his head and retain his walking-stick dangling in the air. There are countless difficulties to be surmounted, such as the feeling of repulsion, or even disgust, at being brought into proximity with monstrous spiders like Dr Walsh’s pets; but as this species, unlike the Lycosa tarantula and other poisonous and dreaded kinds, is harmless to human beings, and as their silk would evidently become a valuable addition to the resources of the loom as well as the boudoir, any such feelings and other obstacles would probably soon be overcome. The French—always in the van in such matters, notwithstanding their comparatively limited colonial opportunities—are not likely to allow this curious and interesting occupation to go begging for want of experiment and patience. But Britain—with her numerous dependencies and myriads of active, scheming, inventive brains scattered all over the globe—occupies a peculiarly favourable position to test and localise such an industry.