Obfervations on Electricity, 285 
But the mtenfity of the very denfe charge on the talc was fo 
low as to aftord an explofion of no more than about one-tenth 
of an inch, while that of the glafs jar it was compared with 
exploded through about five inches. 
The perforation of glafs by the long fpark, or by the fpark 
through oil or cement, feems to depend on the very great i'n- 
tenfity of the electricity which has not time to diffufe itfelf, 
but charges a minute part of the furface very high. 
37. Mufcovy talc * being a very perfect non-conductor, and 
capable of being divided into plates of lefs thicknefs than one 
two-hundredth part of an inch, I made many experiments 
with it, which are too numerous to enter into this Paper, In 
confequence of its great capacity it gives very ftrong fhocks. 
Contrary to the affertion of Beccaria, I found that its la- 
minae are naturally in ftrong oppolite ftates of electricity, and 
fla(h to each other when torn afunder in the dark. A large 
piece being fplit in two, the parts were found to be in oppolite 
ftates. The greateft care was taken in thefe experiments to 
avoid friction, and to ufe fuch pieces as had never been excited, 
nor brought near the machine. 
38. The inoft plaufible objection againft the probability of 
danger from the returning ftroke of the Earl of Stanhope is, 
that the quantity of electricity in an animal is too fmall to pro« 
duce any mifchievous effect. This the noble author has anfwered 
by remarking, that the quantity has not been (hewn to be 
fmall My experiments with talc (hewing that it naturally 
pofl’effes much eletricity, led me to inveftigate the quantity 
which a man may contain. I melted fealing wax upon 
Bennet’s electrometer with a burning glafs, and found it pro- 
* I am not certain whether Henley or Beccaria firft nfed this fubftance ; 
hut little attention was paid to it by either, f Phil, Tranf, Vol. LXXVII. p. 143, 
Vol. LXXIX. T t duced 
