_ 
118 On North American Spiders. 
‘Several circumstances concur to show the phenomenon of ascent 
to be electric: the propelled threads do not interfere with each other; 
they are divellent, and this divergence seems to proceed from their 
being imbued with similar electricity ; and the character of that elec- 
tricity appeared to us to be an interesting subject for subsequent re- 
search. When a conductor is brought near the thread by which it 
suspends itself, but, above all, to the flocculi or balls, they are con- 
siderably deflected from the perpendicular, and the horizontal fibre 
is attracted by the point: when a stick of excited sealing-wax was 
brought near the thread of suspension, it seemed to be repelled; 
consequently the electricity of the thread is negative. The descent 
of the thread is instantly determined by bringing over it the excited 
sealing-wax. . On the 3d of July, 1822, at 4 P.M., thermometer 
66° F., when two aéronautic spiders, on separate threads, were 
brought. near to each other, a mutual repulsion supervened. 
In one experiment made, the ascent of the insect was so slow 
and tranquil, from the humidity of the lower atmosphere and wet 
ness of the terrestrial surface, that I could easily catch it by follow 
ing its progress: it moved in a plane parallel to the point of departure. 
On the 4th of August, 1822, at 3 P. M., thermometer 66°, the a 
cent was slow and beautiful, the little aéronaut rising regularly in the 
vertical plane. It was distinctly perceived, from the steady fixation 
of the eye and favorable angle of vision, until it had attained an ele- 
vation of at least thirty feet, and was finally lost in the vanishing point 
of elevation. 
“ A variety of phenomena unite their testimony in favor of the col- 
clusions formed, and from what we consider the direct method of in- 
uction. Were the thread not electrical, we may be asked how tt 
could be propelled through the atmosphere in the vertical plane, a 
remain there, contrary to the laws of gravitation? It is indeed re- 
markable, that the threads should always remain in the precise plane 
in which they are propelled, nor swerve from it. The constant rela- 
tive separation finds an analogy in similarly electrified pith-balls, * 
the divergence of the filaments in a glass plume, placed on the co” 
ductor of an excited electrical machine, and the electric state of the 
‘atmosphere will always be found to modify the phenomena. ~ 
transit of the thread through a resisting medium, without its suffering 
deflection in its path, seems to prove it imbued with a power supe 
rior to, and able to overcome, that resistance.” 
