ELECTRIC COLUMN. 
S 
10 
A 
but by an 
increased 
qn;iiitity of 
elecu'icity. 
De Saussnre’d 
observations 
on tUc daily 
changes of 
atinospberic 
electricity. 
related In my former paper, which proves that the increase of 
heat, far from increasing its power, diminishes it, by drying the 
papers, and thus lessening their conductive faculty. This experi- 
ment is related in my paper on Mr. Singer s column, at p. 103 
of your Journal for October, in the following manner. 
“ Having dried every part of a column, by placing them near 
the fire of my chimney, when I remounted it in that state, 
” the electremotion had almost ceased ; but having dismount- 
“ ed it, and laid all the pieces separately on a table, where they 
“ remained the whole night, acquiring thus the degree of 
moisture of the air in the room, when I mounted it again, 
the same electro-motion was restored.” 
I’his experiment proves, that the effect of the sun’s rays on 
the column cannot be attributed to an increase of heat j and 
there remains only one explanation, that of the production of a 
new quantity of electric fluid by the sun’s rays. This con- 
clusion will carry me farther, as it recalls M. De Saussure’s 
observations on the atmospheric electricity, related in the 2d 
vol. of my work Idees Sur la Meteorologie, p. 41 1, correspon- 
dent with my observations on the progress of heat ia the 
atmosphere in the course of the day, detailed in the same work. 
M. De Saussure, to whom experimental philosophy is 
indebted for many important discoveries, made his observations 
on the atmospheric electricity with an apparatus which I had 
seen before I left Geneva, and which I must first describe.— 
He had erected, on a terrace projecting considerably from his 
house in front of a plain, a mast about IQO feet high, having at 
the top an insulated metallic rod, from which a metallic wire 
descended down al most to the level of the terrace, whence it passed, 
for insulation, through a glass tube in the wall of a summer- 
house, and was there connected with a pair of pith balls, mov- 
ing at a proper distance from a scale, and their degrees of 
divergence indicated th« degrees of the atmospheric electricity. 
M. De Saussure gives the general results of his observations 
as follow's. " In winter, the season in which I have observed 
“ most regularly the electricity in the serene air, it appears to 
me that the period in which it is the w'eakest, is between the 
time 
