C 374 ] 
to the floor. But it is to be remember’d in this ex- 
periment, that no electricity is perceptible either in 
vacuo, or upon any part of the machine, as above- 
mentioned, unlefs at the fame time the prime con- 
ductor is made ufe of; for, without that, there will 
be no diminution of the denfity of the electricity in 
the machine, as the quantity taken from the cufhion 
by the globe in its rotation is returned upon it 
again the next revolution, the cufhion being the flrll 
non-eleCtric, which offers itfelf : but this I have 
have confider’d at large, as may be feen in the Phi - 
lofophical Tranfattiom *. This experiment therefore, 
in which the electricity is feen, without any preter- 
natural force, pufhing itfelf on through the vacuum 
by its own elafficity, in order to maintain the equi- 
librium in the machine, which had loft part of its 
natural quantity of eleCtricity by the prefent opera- 
tion ; this experiment, I fay, I do not fcruple to 
confider as an experimentum crucis of the truth of 
the dodtrines here laid down ; to wit, not only that 
the eleCtricity is furnifh’d by thofe bodies, hitherto 
called non-eleCtrics, and not by the eleCtrics per Je || ; 
but 
* Vol. XLV. P . 96. 
|| Since the communication of this paper to the Royal Society 
in February 1752, viz. in the fucceeding fummer, the truth of 
this dodlrine is put out of all doubt by the difcovery made in 
France, in confequence of Mr. Franklin’s hypothecs, of being 
able, by a proper apparatus, to colleft the ele&ricity from the at- 
mofphcre during a thunder-dorm, and to apply it to the ufual ex- 
periments, which demonftrates, that the matter of thunder and 
lightning and that of electricity are one and the fame. I hat the 
electricity did not proceed from the glafs, or other electrics per fe y 
as they had been ufually called, I firft difeover’d in the year 1746.' 
