* 201 
Mr. cavendish on the Torpedo. 
in the nature of Mr. lane’s electrometer mult be ap- 
proached, before the- jars would difcharge themfelves. 
I then electrified the fame jars again in the fame degree 
as before, and feparated all of them from the conductor 
except one. It was found, that the 'diftance to which the 
knobs mult be approached to difcharge this fingle jar 
was not fenfibly lefs than the former. It was alfo found, 
that the divergence of the electrometer was the fame 
after the removal of the jars as before, provided it was 
placed at a confiderable diftance from them : from which 
laft circumftance, I think we may conclude, that the force 
with which the fluid endeavours to efcape from the tin- 
gle jar is the fame as from all the jars together. 
It appears, therefore, that the diftance to which the 
fpark will fly is not fenfibly affected by the number or 
fize of the jars, but depends only on the force with which 
they are electrified ; that is, on the force with which the 
fluid endeavours to efcape from them : confequently, a 
large jar, or a great number of jars, will give a greater 
fhock than a fmall one, or a fmall number, electrified to 
fuch a degree, that the fpark fhall fly to the fame dif- 
tance; for it is well known, that a large jar, or a great 
number of jars, wall give a greater fhock than a fmall 
one, or a fmall number, electrified with the fame force. 
In trying this experiment, the jars were charged very 
weakly, inlomuch that the diftance to which the fpark 
would fly was not more than the 20th of an inch. The 
electrometer I ufed confifted of two ftraws, 10 inches 
long, hanging parallel to each other, and turning at one 
Vol. LXVI. Dd end 
