Obfervaiions in EkBricity. 39-r 
from it, the electrometer which communicated with the 
tin plate, that is, with the under fide of the electric plate, 
immediately opened with negative electricity. If by 
touching the electrometer I take that electricity off, the 
electrometer will not afterwards diverge. But if now,, 
©r when the electrometer diverges, I prefent my hand 
open, or any other uninfulated conductor, at about one or 
two inches over the eleCtric plate, without touching it,, 
then the pith- balls .diverge; or, if they diverged before, 
they come together, and immediately diverge again with 
pofitive electricity. — Remove the hand, and the balls 
come together ; approach the hand, and they diverge,, 
and fo on. 
If while the pith-balls diverge with negative electri- 
city, I put the metal plate upon the wax, the balls ap- 
proach each other for a little time, but foon open again 
with the fame, that is with negative electricity. 
If, whilft the metallic lies upon the eleCtric plate, I 
touch the former, the. electrometer immediately diverges' 
with pofitive electricity, which if by touching the elec- 
trometer I take off, the electrometer continues without 
divergence. I touch the metal again, and the electro- 
meter opens again.; and fo on for a confiderable number 
of times, until the metal plate has acquired its full 
charge. On taking now the metal plate up, the electro- 
meter 
