Page:The history of silk, cotton, linen, wool, and other fibrous substances 2.djvu/194

 redoubles it with additional threads. On trying its strength she is not contented with the test of pulling it with her legs, but drops herself down several feet from various points of it, as we have often seen, swinging and bobbing with the whole weight of her body. She proceeds in a similar manner with the rest of the frame of her wheel-shaped net; and it may be remarked that some of the ends of these lines are not simple, but in form of a Y, giving her the additional security of two attachments instead of one."

In constructing the body of the nest, the most remarkable circumstance is the using of her limbs as a measure, to regulate the distances of her radii or wheel-spokes (See Fig. 12. Plate IV., which represents the geometric net of the "Epeira diadema"), and the circular meshes interwoven into them. These are consequently always proportional to the size of the spider. She often takes up her station in the centre, but not always, though it is so said by inaccurate writers; but she as frequently lurks in a little chamber constructed under a leaf or other shelter at the corner of her web, ready to dart down upon whatever prey may be entangled in her net. The centre of the net is said also to be composed of more viscid materials than its suspensory lines,—a circumstance alleged to be proved by the former appearing under the micoscrope studded with globules of gum. "We have not been able," says Mr. Rennie, "to verify this distinction, having seen the suspensory lines as often studded in this manner as those in the centre."

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,