C 3 63 ] 
removal of the air, the electricity did pervade the 
vacuum to a confiderable diflance, and did manifeft 
its efteCts upon any non-eleCtric fubftances, which 
did terminate that vacuum ; and that by thefe means, 
originally-eleCtric bodies, even in their moft perfect 
ftate, put on the appearance of non-eleCtrics, by be- 
coming themfelves the conductors of electricity. 
I had not fo long delayed the illuftration of thefe 
opinions by the experiments, which put me in pof- 
feffion of them, but that I was not only diverted 
therefrom by very various avocations, but de- 
firous of giving them a ftill greater degree of per- 
fection, in order to place the above deductions be- 
yond all controverfy. The executing the apparatus 
neceffary hereto was not eafily furmounted : I unfuc- 
celsfully tried feveral artificers, who were not able to 
arrive at the nicety, which I thought neceffary in the 
conftruCtion of my inftruments. Animated however 
by a late very honourable occafion, and affifted by 
Mr. Smeaton in the completing my apparatus, the 
event fully anfwered what I propofed ; although 
from the experiments I had made before the com- 
munication of the above accounts, I was fully con- 
vinced of their truth. I had other opinions indeed, 
which did ftill require a further degree of demon- 
flration. 
To make thefe experiments fucceed, two things 
were more particularly required j firft, that the in- 
fide of the glaffes made ufe of fhould be perfectly 
dry ; and therefore it was neceffary, that their internal 
furface fhould be expofed to the wet leathers, ufually 
employed in pneumatic experiments, as little as might 
poffibly be j otherwife, the vapours, arifing therefrom 
Z z 2 in 
