KLECTRrC COLUMN. 
375 
The column was then placed before a fire, in a situation where Obm-rvation.* 
, , ... , ouiheotrecl of 
the thermometer rose to 80. In ten minutes it was removed, tj,,. 
and applied to the electrometer ; the gold leaf struck the sides 
‘ ‘ ° powtrot lue 
of the glass 37 times in OO seconds. The column was re- column. 
turned to its former situation until cooled to the original tem- 
perature : it then produced nine Strikings in GO seconds. It 
w’as placed again before the fire for ten minutes, and, on its 
application to the electrometer, produced 36 strikings in 60 
■ seconds nearly. 
Some effects, nearly analogous to these, were observed with 
'the usual voltaic apparatus, by M. Desseignes His experi- 
ments are detailed in the Journal de Physique, vol. 73, p. /3 
and 417. I shall probably refi'r to them in a fuinre paper. 
I think it nece.ssary to mention here a caution essential to the 
uniform action of the electric column. That instrument 
should n^’er be left for any considerable time w itb its opposite 
‘ends connected by a conducting substance, J as is the case when 
it is simply laid on a shelf or table, or in a drawe.r ; for, under 
■such Circumstances, it will apj^ear to have very little power 
when first applied to the cap of an electrometer, and will re- 
quire some time to recover its original intensity. The best 
: arrangement, when the column is Ifiid by, is to place it resuog 
I on two sticks of sealing wax, so that its brass c.aps may be kept 
.at the distance of half an inch from the table, or othei cor.- 
vlucting surface on which it is disposed. 
Prinfes Street, Cavendish Sijuare, 
Dec. I3th, IS 13. 
