3G Mr. Children’s Account of some Experiments 
directly in point, cannot be considered as foreign to the sub- 
ject of this Paper. It has been urged, as one proof of the 
non-identity of the common electricity, and that given out by 
the Voltaic apparatus, that in the latter there is no striking 
distance. That objection, however, must cease. I took a small 
receiver, open at one end ; through perforations in the oppo- 
site sides of which were placed two wires, with platina points, 
well polished : one was fixed by cement to the glass, the other 
was moveable, by means of a fine screw, through a collar of 
leathers, and the distance between the points was ascertained 
by a small micrometer attached. This receiver was inverted 
over well dried potash over mercury, and suffered to stand a 
couple of days, to deprive the air it contained, as thoroughly 
as possible, of moisture. The 1250 plates being excited pre- 
cisely to the same degree as the great battery, mentioned in 
the beginning of this communication ; and the little receiver 
placed in the circuit, I ascertained its striking distance to be 
~th of an inch. That I might be certain that the air in the 
apparatus had not become a conductor by increase of temper- 
ature, I repeated the experiment several times with fresh cool 
air, and always with the same result ; but perhaps it will be 
objected, that the striking distance was so small, as not to 
afford a satisfactory refutation of the argument alluded to, 
when it is considered to how very great a distance, compara- 
tively, the spark of the common electrical machine can pass 
through air. The answer to this is obvious: increase the 
number of the plates, and the striking distance will increase ; 
for we see throughout, the intensity proportioned to the num- 
ber, and it probably may be carried to such extent, as even to 
pass through a thicker plate of air, than the common spark. 
