we 
Hare’s Single Leaf Electrometer. ol 
incapacity of the Deflagrator, and Voltaic series in the usual 
- form, to act, when in combination with each other ; must 
Justify us, in considering the former, as a galvanic instru- 
meot, having great and peculiar powers. | 
Since the above was written, | have tried my series ‘of 
300 pairs. The projectile power, and the shock, were 
proportionally great, but the deflagrating power was not 
increased in proportion. The light was so intense, that, 
falling on some adjacent buildings, it had fully the appear- 
ance of sunshine. Having had another series of 300 pairs 
made for Dr. Macnevin of New-York, on trying it, | con- 
nected it with mine, both collaterally, and consecutively, 
so a8 to make in the one case a series of six hundred,—in 
the other a series, half that in number,but equal in extent 
of surfaces, The shock of the two, consecutively, was ap- 
parently doably as sévere, as the shock produced by 
one; but the other phenomena seemed to me nearly equal- 
ly brilliant, in either way. <a seit 
The white globules which you noticed, were formed co- 
piously on the ignited charcoal, especially in vacuo. ~ 
have not had leisure, to test them, being arduously occu- 
pied, in my course of Lectures, and in some efforts to im- 
prove the means of experimental illustration. 
Constitutes the top of the instrument. Opposite to this 
Single leaf, is a ball, supported on a wire, which may 
made to approach the leaf ; or recede from it, by means of 
ascrew. Above the instrument, is seen a disk of copper, 
with a glass handle.* The electricity produced by the 
Contact of copper and zinc, is rendered sensible in the fol- 
lowing manner. Place the disk of copper, on the disk of 
zine, (which forms the canopy of the Electrometer) : take 
€ micrometer screw in one hand, touch the copper disk 
*For the experiment with this electrometor a metallic handle would an- 
‘wer. Its being of glass enabled me to compare the indication, thus 
tained, with that obtained by a condenser. 
