396 ON THE ASCENT OF THE SPIDER, &C. 
can find no reasonable cause but in the subtilty of electri- 
city and excitation of that mighty power. An illustration 
somewhat connected with the question is found in the pro- 
pulsion of fine threads from melted wax connected with the 
conductor of the electrical machine in action, the threads 
being received on the surface of paper. 
When the superior regions of the atmosphere are charged 
with positive electricity, while the threads are imbued with 
negative electricity, ascent into the atmosphere becomes a 
necessary consequence. 
It is difficult to ascertain what part this ascent into the 
atmosphere subserves in the economy of Nature. Whether 
the spider becomes food for other insects, remains a ques- 
tion ; but I have, in several instances, found that, while it 
oscillated, some prowling Vespa, or wandering Musca, has 
snapt up and carried off my " Aranea aeronautica.'^'' 
Macclesfield, ) 
October 31. 1828. j 
