CHAPTER III.
MANUFACTURE OF SILK BY SPIDERS.
Our history of the silk manufacture among insects would be incomplete without a notice of the labours of spiders. Not only do these insects produce filmy webs to entrap their prey, but they also spin, for the protection of their eggs, a bag not much unlike the cocoon of the silkworm. At the beginning of the last century a method was discovered of procuring silk from these spiders’ bags, and of making it into several useful articles. The experiments took place in France, and it was there discovered that two species of spider in particular produced strong and beautiful silk, capable of being usefully employed. The structure of these insects was closely examined by the celebrated naturalist Réaumur, and he found that the silk is spun from five papillæ, or small nipples, placed in the hinder part of the body; these serve the purpose of so many wire-drawing irons, to mould a gummy liquor, which dries as it is drawn out and exposed to the air.
SPINNING APPARATUS OF THE SPIDER.
(Greatly magnified.)
On pressing the body of a spider, the liquor flows into these nipples, by applying the finger against which, distinct threads may be drawn out through the numerous openings; and, what is very astonishing, every separate thread is made up of innumerable smaller threads, so that Réaumur thought himself far within the limits of the truth when he stated that each of the five nipples supplied one thousand separate fibres, in which case the slender filament of the spider’s nest must be made up of five thousand fibres. By applying the whole, or a part, of this apparatus to her work, the spider can make the thread stout or fine at pleasure: thus the webs for entrapping flies are very slight and fragile; but the nest for securing the eggs is much stronger, to afford them shelter from the cold. The threads are wound loosely round the eggs in a shape similar to that of the silkworm’s cocoon. The colour of the silk is generally grey, becoming blackish on exposure to the air: sometimes it is pale yellow, and also of very fine quality; but this is the production of comparatively rare species, which could not be depended on for the purposes of manufacture. A spider’s nest preserved by the writer during the last winter was of a beautiful yellow, almost approaching that of the cocoon of the silkworm. As spring approached it increased in bulk and became rather paler, until at last a dark appearance in the centre betokened the bursting of the eggs. At the present time (April 10th) ninety-six small yellow-bodied spiders have come forth, and are actively engaged in weaving their delicate webs across the glass which contains them. A muslin cover admits air to the interior, and these minute insects appear perfectly healthy although deprived of their natural food. Some sugar was placed in the glass, but they do not appear to have consumed any of it, although some of them have been hatched for more than a fortnight. From the appearance of the nest, more of these spiders yet remain to be hatched.
In the French experiments, spiders’ nests in large quantities were collected from the trunks of trees, corners of windows and vaults, and eaves of houses at the time above mentioned, and from these a new kind of silk was obtained by M. Bon, who declared it to be in no respect inferior to that of the silkworm. It was afterwards proved that he was greatly mistaken in this respect; yet the spiders’ silk readily took all kinds of dyes, and was actually wrought into stockings and gloves, specimens of which were presented by M. Bon to the Royal Academy of Paris, and also to the Royal Society of London. His method of preparing the silk was as follows:—
Twelve or thirteen ounces of the bags were beaten with the hand, or by a stick, until they were entirely free from dust. They were then washed in warm water, which was frequently changed, until it was no longer discoloured by the bags. They were next steeped in a large quantity of water, wherein soap, saltpetre, and gum-arabic had been dissolved. The whole was then set to boil over a gentle fire for three hours. Lastly, the bags were rinsed in clear warm water, and set out to dry. They were then fit for the operation of carding, which was performed with very fine cards, and thus silk of a peculiar ash colour was obtained, which was spun without difficulty.
SPIDER’S NEST ATTACHED TO A FLAT SURFACE.
