The history of silk, cotton, linen, wool, and other fibrous ... - Cd3wd.com

162 CULTIVATION AND MANUFACTURE OF SILK.
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 httle vacant spaces between them, the Ught is not equally
reflected, and the lustre of the material is consequently inferior
to that in which a solid thread is used.
3. A great disadvantage of the spider's silk is, that it cannot
be wound off the ball like that of the silk-worm, but must ne-
cessarily be carded. By this latter process, its evenness, which
contributes so materially to its lustre, is destroyed.
The ferociousness and pugnacity of the spiders are not ex-
aggerated ; they fight hke furies. Their voracity, too, is al-
most incredible, and it is very questionable whether the mere
collection of flies sufficient to feed a large number of the spi-
ders would not involve an amount of expense fatal to the proj-
ect as a lucrative undertaking. The strength of the spiders'
filament is, if anything, overstated by Reaumur. Deficiency
of lustre arising from the carding of the filaments is common
to the spider-fabric and to spun silk ; this objection would, per-
haps, not be of very great weight but for the decisive calcula-
tion by which Reaumur showed the comparative amount of
production between the spider and the silk-worm.
The largest cocoons weigh four, and the smaller three grains
each ; spider-bags do not Aveigh above one grain each ; and,
after being cleared of their dust, have lost two-thirds of this
weight ; therefore the work of tioelve spiders equals that of
only one silk-worm ; and a pound of spider-silk would require
for its production 27,648 insects. But as the bags are wholly
the work of the females, who spin them as a deposit for their
eggs, it follows that 55,296 spiders must be reared to yield one
pound of silk: yet this will be obtained only from the best
spiders ; those large ones ordinarily seen in gardens, (fcc, yield-
ing not more than a twelfth part of the silk of the others.
The work of 280 of these would therefore not yield more silk
than the produce of one industrious silk-worm, and 663,552 of
them would furnish only one pound of silk !
Although Reaumur's report completely extinguished Mr.
Bon's project in France, it was revived in England two or
three times in the early part of the last century. Swift has