L 2 9+ ] 
they had contraCled was ; and previous to the expe- 
riment, I conjectured it would be negative ; fuppohng 
that the difcharge from the infide coating, in an 
interrupted circuit, was not able to fupply the outfide 
fall enough. And hnce, the larger the infulated 
body was, the greater quantity of the eleCtric fluid it 
was capable of receiving, or parting with, and con- 
fequently the more fenflble the effect would be ; I 
began with fufpending on filken firings, a pafleboard 
tube, covered with tinfoil, feven feet long and four 
inches thick, with large knok at each end ; and a 
brafs ball (at the end of an iron rod, which com- 
municated with the outfide of the jar) was placed 
within about a quarter of an inch of it; while the 
difcharge was made through an infulated interrupt- 
ed circuit, no part of which was lefs than two feet 
from the infulated tube. On making the explofion, 
the fpark appeared as I expeCted ; but, to my great 
furprize, I could not find that either pofitive or nega- 
tive eleClricity was communicated to the infulated 
tube. Neither the pith balls, nor the fineft threads 
diverged, or moved in the leaft, at or after the dif- 
charge ; though, everything elfe remaining in the 
fame ftate, the leaft fenfible electricity communi- 
cated to this tube (a quantity fo ftnall as hardly to be 
vifible, in the form of a fpark, at the time of com- 
munication) made the balls and the threads feparate 
to a great diflance, and would have kept them in a 
ft ate of divergency more than an hour. Left a fmall 
degree of motion or divergency fhould efcape my 
notice, while I was intent upon making the dif- 
charge, I had an afliftant along with me, whofe eye 
was 
