THEOaY OF GALVANISM. 
105 
for Us explanation I must recur 6rst, also, to some of my pa- Excitement of 
pers In your Journal. jjalvanic elec- 
^ ■' truitv, and 
In your number for October, 1810, I explained the function phenomena of 
of the electric colunui as an aerial electroscope. This last pro- 
perty, which was manifested by the motion of a pendulum, I 
did not immediately discover, considering only that pendulum 
in the view that I had intended it at first, to produce the trans- 
mission of the electric fluid from one extremity to the other 
of that apparatus. The columns which I use for that purpose, 
are terminated at both their extremities by a large brass hall : 
these balls being brought to a small distance from each other, 
the pendulum is suspended between them, in communication 
with the positive extremity of the column : now, its motion 
points out, almost to the eye, the transmission of the electric 
fluid from the positive to the negative extremity in that inter- 
rupted circuit. When the pendulum returns to the positive 
ball, it soon recedes from it, is th^n carried to the negative 
ball, and so on alternately ; giving thus the idea of a bucket, 
. taking water in one pool, and pouring it into another. That 
. this process is a real transmission of electric fluid from one 
of the extremities to the other, is proved by the constant 
alternating motions of gold- leaf electroscopes, when connected 
with these extremities. 
By observing some time this interesting phenomenon of the 
alternate strikings of the pendulum, I come to take notice, 
that they difl'ered in frequency, not only from one day to ano- 
ther, but in difierent parts of the same day ; and I could not 
ifind any connection of these changes with either heat or mois- 
ture, which had very little variations in my room, as can be 
• seen from the tables of my observations, with all their circum- 
stances, in the same number of your Journal. 
Such is the phenomenon which I attributed to the changes 
of the electric sHte of the ambient air, being led to this con- 
clusion by the discovery of Volta on the cause of the motions 
of the balls in our electroscopes, whish discovery I consider as 
i a very important era in the electric science, as arc many others 
of that juitly-celebrated experimental philosopher ; fiw to him, 
VoL. XXXVI.— No. 160'. I in 
