[page] 1437

Aeronaut Spiders. — If your correspondent "H. K." has an opportunity of perusing the volume of Darwin's Naturalist's Voyage Round the World in H.M.S. Beagle, he will find much there to amuse him in the way of aëronaut spiders. One or two quotations out of many from Mr. Darwin's book will be sufficient to substantiate the correctness of "H. K.'s" observations:—

"December, 1833: repeatedly observed the same kind of small spiders, either when placed or having crawled on some little eminence, elevate its abdomen, send forth a thread, and then sail away horizontally, but with a rapidity which was quite unaccountable. On several occasions when the Beagle has been within the mouth of the Plata the rigging has been coated with the web of the gossamer spider. The ship was distant 60 miles from land, in the direction of a steady though light breeze. Vast numbers of a small spider, about one-tenth of an inch in length, were attached to the webs. There must have been some thousands on the ship."

Mr. Darwin accounts for the rising of the spider by the effect of an ascending current of heated air. Such upward currents it has been remarked are also shown by the ascent of the flame of fires and also of soap bubbles, which will not rise in an indoors room. Hence, says Mr. Darwin, "there is not much difficulty in understanding the ascent of the fine lines projected, from a spider's spinners, and afterwards of the spider itself." W. M.