On North American Spiders. : 119 
“Bennet and other electricians have long ago proved, that the im- 
pulse of air on a delicate electroscope invested it with electricity ; 
and this, if proved in the one case, must of necessity be admitted in 
the other. In the Mediterranean, Mr. Black appéars to have ascer- 
tamed that winds, or currents of vapor of some continuance, are 
negatively electrical, and the land breeze in a state of positive elec- 
tricity. It seems deducible, therefore, that an electrical excitement 
may be the consequence of such currents; and it seems equally ob- 
Vious that insects are sufficiently sensible to atmospherical electricity. 
Thus Huber seems to have proved, that the secretion of honey is 
intimately connected with electricity; and that bees are far more 
active and laborious before a storm, and when the wind is south and 
the air warm and humid, than at other times: and Kirby and Spence 
also observe, that ‘insects seem particularly excited by a high elec- 
tric state of the atmosphere, and are then found more numerous on 
the wing than at ordinary periods, and towards evening; and that, 
some time before the storm comes on, various kinds may be then 
seen, that do not appear at ordinary times: but immediately before 
the storm, all disappear.’* D’Isjonval observes, that ‘animals are 
affected by natural electricity; but no one more than myself and my 
spiders.” He had found, by repeated observations, that the length of 
the spiders’ threads corresponded with the electrical state of the at- 
Mosphere: for in wet and stormy weather they were short, and in 
fine Weather were proportionably long. Now, as there may exist 
other causes sufficiently powerful to act as excitants, as well as a cur- 
Tent of air, the question remains as it was: besides, apart from an 
effect analogous to electrical excitement, the modus operandi of a 
Cuttent of air seems most obsure and perplexing.” 
. y Lussac considers the ascent of clouds, in the regions of air, 
Sutirety. ascribable to the impulse of ascending currents, arising from 
€ difference of temperature between the surface of the earth and 
© atmosphere at great elevations.” ‘But the fact proves that 
are replenished with electricity, and the sunbeam which im- 
on them may be the medium of supply.” “ When the — 
tis Rae is Woven on some aérial plane, its continued buoyancy is 
ne snaccountable than the floatage of the sy if the aie 
vlain uses be similar: and as the ‘cloud of night’ sinks upon ee 
"2 $0 does the gossamer spider revisit the earth; and as clouds 
Pingeg 
Mer tis 
* Th 
€ i we ee gs ci eco 
extraordinary activity of the swallow on these occasions is a manifest proof. 
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