154 FLYING SPIDERS. 
favorable occasions I am constantly extending their amount, and 
as often do I find my deductions supported, namely, that the entire 
phenomena are electrical. In clear, fine weather the air is invari- 
ably positive; and it is precisely in such weather that the aëro- 
nautic spider makes its ascent most easily and rapidly, whether it 
be summer or winter. I have often seen this in winter, during an 
intense frost, a circumstance which renders the action of warm 
currents of air, as accessory to its flight, something more than 
questionable. Our aëronaut may be met with in its descent over 
the Mer de Glace as well as over the Lake of Geneva; and it will 
take flight as readily from a point over the frozen sea as from the 
heated surface soil of the valley of Chamouny. 
“Several circumstances concur to shew the phenomena of as- 
cent to be electric. The propelled threads do not interfere with 
each other; they are divellent, and this divergence seemed to pro- 
ceed from their being imbued with similar electricity, and the 
character of that electricity appeared to me to be an interesting 
subject for subsequent research. ...... When a metallic con- 
ductor is brought near to the suspended spider, it disarranges its 
projectiles, and the insect, conscious of some counteracting agency, 
coils up its threads. 
repulsion supervened; and when one was brought in momentary 
n s 
contact with the other, it immediately fell lower in the perpen, 
dicular plane. 
The manner in which the thread starts from the body is difficult 
to determine, on account of the small size of the spiders. One 
theory is that the spider must attach one end of its thread ~ a 
fixed object, so that the wind may have a loop to blow against. 
Some think it more probable that a small quantity of gummy 
material is emitted from the spinnerets and drawn into a thread 
by the current ;* others, that the spinnerets of opposite sides are 
he ee 
* Rennie’s Insect Architecture, p. 881. 
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