fnall Quantities of EleCtricity. y 
then bring them near to each other, and after having adjutted 
them properly, fo that the (lips may hang parallel and fmooth, 
I force the pieces of paper, which now touch each other, be- 
tween the two fides of a fort of pincers made of brafs wire, 
which are fattened to the under part of that piece which 
forms the top of the electrometer : and, in order to change 
thofe flips when fpoiled, I keep in a book feveral flips of gold- 
leaf ready cut, and furnifhed each with a piece of paper; fo 
that by this means this electrometer is rendered, in a certain 
manner, portable. 
Befides the way of afcertaining fmall quantities of electri- 
city, by means of very delicate electrometers, two methods 
have been communicated to the philofophical world, by which 
iuch quantities of eleCtricity may be rendered manifett, as 
could not be perceived by other means. The firtt of thofe 
methods is an invention of M. Volta, the apparatus for it 
being called the Condenfer of Electricity , and is defcribed in the 
Philofophical TranfaCtions, Vol. LXXII. The fecond is a con- 
trivance of the above-mentioned Mr. Bennet, who calls the 
apparatus The Doubler of EleCtricity. A defcription of it is 
inferted in the Philofophical TranfaCtions, Vol. LXXVII. 
M. Volta’s condenfer conflfls of a flat and Imooth metal 
plate, furniflied with an inlulating handle, and a femi-con- 
duCling, or imperfectly infulating, plane. When one wifhesto 
examine a weak eleCtricity with this apparatus, as that of the 
air in calm and hot weather, which is not generally fenfble to' 
an electrometer, he mutt place the above-mentioned plate upon 
the femi* conducting plane, and a wire, or fome other con- 
ducting fubttance, mutt be connected with the metal plate,, 
and mutt: be extended in the open air, fo as to abforb its elec- 
tricity ; then, after a certain time, the metal plate mutt: be 
feparated 
