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158 CULTIVATION AND MANUFACTURE OF SILK.
redoubles it with additional threads. On trying its strength she
is not contented with the test of pulhng 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 fonn
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 regu-
late the distances of her radii or whecl-spokes (See Fig. 12.
Plate IV., which represents the geometric net of the " Epeira
diademd'^), 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 Uttle chamber constructed under a leaf or
other shelter at the corner of her web, ready to dart down upon
w4iatever 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 glo-
bules 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 manufactvue 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 in-
genious observer, the sil!c 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,
* Kirby and Spence, Intr. i. 419.