C 556 ] 
there not then a communication between the exterior 
and interior furface of the glafs ? And is it not evi- 
dent, further, that the electric matter, which is per- 
ceived running w'ithin like a torrent of fire, pailes 
through the glafs ? 
When you force a hole through a piece of paper 
or pafteboard, attend to one thing, which I con- 
ftantly obferve. If you electrile the plate of glafs, 
A B , underneath, and that, by means of a thick iron 
wire fomewhat bent, D , you draw the fpark thro’ a 
piece of pafteboard, C, placed upon the metal, with 
which the glafs is coated, the hole will appear in- 
variably larger underneath, than on the top of the 
pafteboard ; and this hole will have an impreftion 
at the place, where the iron wire fhall have been fup- 
ported. Thefe two effects leave no room to doubt, 
but that the ftroke of fire was directed from the 
glafs to the conductor, E, by the bent iron wire. 
Belides, if the electric fire proceeds from the upper 
furface of the glafs, which receives the electricity 
from the under furface, it neceflarily follows, that 
it muft have palled through the whole thicknefs of 
the plate of glafs ; and, confequently, that the glafs 
is not impermeable to the electric fluid. 
