Manifestation of small Portions of the Electric Fluid. 51 
D, A brass pillar whose lever is depressed by the carrier B in 
its revolutions. 
E. A multiplying wheel—very useful—to obviate, as much as 
possible, the effects of dissipation. 
FF. The brass plates between which the carrier is mounted. 
G. A countervailing weight, to render the movement of the 
carrier both light and equable. 
H. A glass pillar; by taking hold of whose handle I, the hind 
plate of the smaller reservoir c may, when necessary, be 
turned backward. The elevated position of this pillar is 
most important; the ascending humidity of the hand, so 
fatal to all delicate experiments, and to which our ordinary 
condensing electrometers are subject, being thus avoided. 
On packing up the instrument, this pillar should be un- 
screwed, and taken from off the plate. 
i. The handle of the glass pillar H just described. 
K. A brass rod suspended from the hind plate of the smaller 
reservoir c, to which itis screwed. This rod is connected 
with, and disengaged from, the earth at pleasure, by means 
of the horizontal brass lever L, which turns from right to 
left upon a centre pin. 
L. The horizonatal brass lever just mentioned. 
M. A gold-leaf electrometer, by which the accumulated fluid is 
" _ examined. A rounded pin, which insures its temporary com- 
munication with the larger reservoir C, is concealed from 
the eye. The chain, though bright, by which it was acci- 
dentally connected with the smaller c at the time of draw- 
ing, is much inferior to a polished wire when delicate ex- 
periments are in question. 
At the back of this instrument, iti the base, adjusting screws 
are properly stationed to regulate the necessary distances be- 
tween all the parallel plates; while, for the security of the hind 
plates of C and c, which may be turned backward by means of 
hinges attached to their respective bases, two suitable stops are 
introduced, 
For the examination of atmospheric and every other kind of 
Giffused electricity which yields a sufficient guanéity, the com- 
bined reservoir c C may, when the operator pleases, be employed 
alone in the usual manner, like our ordinary condensers. 
N. A glass pillar supporting a horizontal brass rod, which rod 
is situate at some distance behind all the plates. 
OOO. The last-mentioned horizontal brass rod, occasionally con- 
nected by a chain or spiral brass wire with the back of 
the source A; thus enabling the operator (the electrome- 
ter being always in such case withdrawn from the larger 
D2 reservoir 
