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116 ~ On North American Spiders. 
Miscellaneous Remarks and Citations. 
The subject examined, so sagaciously, one hundred and sixteen 
years ago, by the philosophical child, remains nearly as he left it, 
Other and recent writers also adopt the hypothesis of the ascent of 
the thread of the flying spider, in consequence of the supposed in- 
ferior specific gravity of its web. It is however obvious that spl- 
ders’ webs of all sorts are in fact specifically heavier than the at- 
mosphere, and under given circumstances fall in that medium; of 
course they cannot, from mere inherent levity, rise in the air, and 
much less raise any weight attached to them. Upward currents in 
the atmosphere, when they exist, will it is true account for the as- 
cent of the web, and it may perhaps ascend with sufficient power 1 
elevate the spider. ‘There is, however, under given circumstances, 
a remarkable constancy in the power exerted by this insect, in caus 
ing his own web to become buoyant, and often to such a degree 
that he mounts, sometimes, many hundred feet into the air, above 
the trees, and towers, and steeple tops, and he rides there with more 
security than an aéronaut in the car of a balloon; it seems scarcely 
probable that this upward tendency can arise entirely from currents, 
which, as we observe when feathers are afloat, carry light bodies 
very irregularly in every direction; a state of things that would be 
inconsistent with the economy and safety of the flying spiders. Per 
haps the most plausible hypothesis, as to the cause of the ascent of 
the thread of the aéronautic spider, is that stated by Mr. John Mur 
ray :* he attributes it to electricity, and we cite the following stal 
ments from his work, as introductory to his conclusion, which we wi 
presently cite, in his own words. 
It appears that the ascent of the aéronautic spider is essential to 
ae existence,} and the great numbers of these wingless insects $ 
ciently account for the abundance of the gossamer, and of the float- 
ng and fixed threads and tissues, that are so often scen. ’ Sometimes 
large tracts of ground are covered with them; two thousand wel? 
wf once obtained in half an hour, and baskets full may be collected; 4 
+ seen by Mr. White, Sept. 21, 1741: also, at Bewdley, in Woree® 
tershire, Sept. 16, 1822, between 11 A.M. and 2 P.M., it was ob 
served that the whole atmosphere seemed to be a tissue of cobwebs 
falling rapidly; the temperature was 72° Fah. Some of the tissues 
a a oo 
SAREE Rae cn RN ATO di OULD I 
# Mi ‘ 
; Peter in Natural History. Second edition. London: 1830. 
sit probabty finds much of its food among the flying insects of the atmosphere 
