OBSERVATIONS AND EXPERIMENTS 
on 
AERONAUTIC SPIDERS, 
MADE CHIEFLY WITH A VIEW 
TO ASCERTAIN THE MEANS BY WHICH THEY 
EFFECT THEIR AERIAL EXCURSIONS. 
—_>—_—_ 
AutHoucH it is well known that spiders frequently 
ascend into the atmosphere through the instrumen- 
tality of fine lines formed of a viscid secretion, which 
proceeds from the mammulz situated at the extremity 
of the abdomen, yet the manner in which these aérial 
journeys are effected still remains involved in obscu- 
rity, and considerable diversity of opinion exists as to 
the particular species of spider by which they are 
undertaken. This deficiency leaves open a wide 
field for speculation ; and, accordingly, we find that 
natural historians have ascribed this interesting oc- 
currence to several distinct causes, such as the agency 
of winds, evaporation, and electricity, the exercise of 
peculiar physical powers with which aéronautic spiders 
have been supposed to be endowed, and the extreme 
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