Obfervations in Eleciricity. 99 
of the plates, when feparated after charging, had a poli- 
tive and a negative furface; and that having replaced 
them, and made the difcharge as in the Leyden experi- 
ment, the electricity of all the furfaces was changed, 
though it appeared to be very ftrong, and continued to 
give repeated dallies of light, when the plates were al- 
ternately clofed, touched, and feparated, as the looking- 
glafs plates above mentioned. If a clean dry uncoated 
plate of looking-glafs was placed between the coated 
plates, either of looking-glafs or crown-glafs, before they 
were charged ; that uncoated plate was always found, 
upon feparating them after charging, to be eleClrified 
negatively oh both its furfaces ; but if it was put between 
the Dutch plates, it acquired, like them, a pofitive and a 
negative electricity . As this phenomenon was not fatif- 
factorily accounted for, it occafioned much converfation 
with refpeCt to Dr. franklin’s theory of the Leyden 
bottle, which I had myfelf (as I imagined) fatisfaCtorily 
explained and even demonitrated. I was, however, 
foon convinced, that that theory is not fo generally 
received as I imagined; for I met with a number of 
gentlemen who not only doubted, but feemed abfolutelv 
to deny it. This induced me to make feme further ex- 
periments, in order (if I could) more fully to illuftrate 
that theory, and to put the matter out of doubt. For 
O 2 
this 
