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

SILKEN MATERIAL OF THE SPIDER. 151
in empty wine-glasses, set in tea-saucers filled with water, to
prevent their escape. When they discovered, by repeated de-
scents from the brinis of tlie glasses, that they were thus sur-
rounded by a w^et ditch, they all set themselves to the task of
throwing their silken bridges across. For this purpose they
first endeavored to ascertain in what direction the wind blew,
or rather (as the experiment was made in our study) which
w^ay any current of air set,—by elevating their arms as we
have seen sailors do in a dead calm. But, as it may prove
more interesting to keep to one individual, we shall first watch
the proceedings of the gossamer spider.
" Finding no current of air on any quarter of the brim of the
glass, it seemed to give up all hopes of constructing its bridge
of escape, and placed itself in the attitude of repose ; but no
sooner did we j^roduce a stream of air, by blowing gently
towards its jjosition, than, fixing a thread to the glass, and
layitig hold of it with one of its feet, by way of security, it
placed its body in a vertical jjosition, with its spinnerets ex-
tended outwards ; and immediately we had the pleasure of
seeing a thread streaming out from them several feet in
length, on which the little aeronaut sprung up into the air.
We were convinced, from what we thus observed, that it was
the double or bend of the thread which w^as blown into the
air ; and we assigned as a reason for her previously attaching
and drawing out a thread from the glass, the wish to give the
wind a j^oint d^appui—something upon which it might have
a jiurchase, as a mechanic would say of a lever. The bend
of the thread, then, on this view of the matter, woidd be car-
ried out by the wind,—^would form the point of impulsion,— ^and,
of course, tlie escape bridge would be an ordinary line doubled."
Such is the opinion of Mr. Rennie, which is strongly corrobo-
rated by what has been said by M. Latreille—than whom no
higher authority could be given. " When the animal," says
he, " desires to cross a brook, she fixes to a tree or some other
object one of the ends of her first threads, in order that the wmd
or a current of air may carry the other beyond the obstacle* ;"
* " L'un des bouts de ces premiers fils, afiii que le vent ou un courant