390 Mr. cavallo’s Experiments and 
pofitive eledtricity, and the metallic removed from the 
eledtric plate appears to be negative. 
This experiment, I find, an.fwers in the fame manner 
if an eledtric plate be ufed which has the fealing-wax 
coating on both fides ; for, whichever fide of this is ex- 
cited, it will adt like the waxed fide of the above de- 
icribed plate, that is, will render the metal plate fet on 
it pofitive, and the oppofite fide will render it negative. 
If, inftead of laying the eledtric plate upon the table, 
it be placed upon an eledtric ftand fo as to be accurately 
inful ated, then the metal plate fet on it acquires fo little 
eledtricity that it can only be difcovered with an eledtro- 
meter; which fhews, that the eledtricity of this plate will 
not be confpicuous on one fide of it, if the oppofite fide 
be not at liberty either to part with, or acquire more of, 
the eledtric fluid. In confequence of this experiment, 
and in order to afcertain how the oppofite fides of the 
eledtric plate would be affedted in different circumftances, 
I made the following experiments. 
Upon an eledtric ftand I placed a circular tin plate, 
nearly fix inches in diameter, which by a flender wire 
communicated with an eledtrometer of pith-balls, which 
was alfo infulated; I then placed the excited eledtric plate 
of fix inches and a quarter diameter upon the tin plate, 
with the wax uppermoft, and oh removing my hand 
from 
