308 
KJ.KCTRIt; COLUMN. 
Former ap- 
paratus rci'cr 
red to. 
falling upon it, which 1 shall describe, after having explained 
why I have observed it but lately. 
In my paper published in your Journal for October, 1812, 1 
have given the figure of an apparatus connected with my first 
electric column, indicating, by the difference in tlie frequency' 
of the strikings of a pendulum, a remarkable effect of the 
difference in the electric state of tire ambient air j for which' 
reason I added to the first appellation of that instrument, that 
of aerial electroscope. 
Exposition of I intended to follow the same observations in an easy manner. 
t*»e same. 
I,ur*rer appa- 
ratus accord- 
iiic to Mr. 
Singer’s 
method : 
by placing the column on a table separated from that on which ' 
1 am differently emploj’ed. The apparatus of the pendulurw 
requiring to be steady for its original function, I was induced t» 
fix it, with the column, on that table ; and for reasons of con- 
venience, I fixed it in a situation that prevented' me frona- 
observing the phenomenon which is now my object,* , 
In the course of the summer I have constructed*'a‘new' 
electric column of HXIO pairs of zinc plates and ‘pieces of 
Dutch-gnilt paper about 2 inches square, with the addition 
made by Air. Singer of a loose piece of paper between the pairs, 
the importance of which I have explained in my former paper. 
The power of this column is so much greater than that'of the 
first, that it produces the oscillation of a pendulum consisting of 
a gilded pith-ball, 4-lOths of an inch in diameter, suspended by_ 
a thin silver wire 5 inches long, communicating, like the former, 
with the positive extremity of the column ; the gilded ball, 
thus suspended, comes down botvieen the same large brass balls, 
one in connection with the positive extremity of the column, 
the other with the negative. 
This apparatus being finished,' it ■was to have been fixed on 
the same table ; but as it promised more interesting observa- 
tions, I placed it opposite to my window, at a certain distance 
from it. The frequency of strikings was at first too great to be 
regularly counted j but having means of changing the distance 
between the large balls, I found by trials, a distance at which 
the strikings continue every day, the •w'hole off the 24 hours, 
Iii«re»icd frft. This phenomenon of the column interested roe, as affording , 
with a diffvr- 
tUt CXpOkUTC. 
8 new 
