Experiments on the variable Action of the Electric Column. 415 
I have commenced a series of experiments on the effects of 
heat applied to various Voltaic combinations, which may possibly 
present an answer to the question proposed in this paper by 
Mr. Ronalds: but, from the necessity of constructing new ap- 
paratus for this purpose, it may be some time ere I am able to 
publish their results. 1 am, sirs, yours, &c. 
To Messrs. Nicholson and Tilloch. G. J. Sincer. 
Experiments on the variable Action of the Electric Column, 
By Francis Ronaxps, Esq. Communicated by Mr.Sincep. © 
Hammersmith, June 10, 1814. 
Very soon after I had constructed a pendulum apparatus si- 
milar in principle to that of M. De Luc described in vol. xxvii. 
page 161 of Nicholson’s Journal, and had observed the variety 
of its action, I suspended an hygrometer and a thermometer near 
it, by which I found that when the latter rose but one degree, 
a difference of four to five vibrations in five minutes took place, 
whilst no such effect occurred if the former advanced two or 
three degrees towards dryness unaccompanied by a correspond- 
ing rise of the thermometer. It was therefore evident that heat 
is the principal cause of the variable action of the electric co- 
lumn. 
The following experiments were made with a gold-leaf elec- 
trometer, in order that they might be: repeated and varied by 
any one who may not be inclined to construct the pendulum ap- 
paratus of M. De Luc’s contrivance, or provide himself with one. 
The negative end of a column consisting of 1000 groups of 
zine and gold paper, inclosed in a glass tube with interposed 
discs of paper as improved hy Mr. Singer, was screwed upon one 
side of a brass tripod, an electrometer on another side, and an 
hygrometer and thermometer on the third side. A glass dish 
was placed under the tripod, and the whole apparatus arranged 
upon the plate of an air pump. 
An observation was generally made every five minutes. In 
the 3d Experiment the mean of several observations is set down 
instead of each, for the sake of brevity. The first columns give 
the time; the 2d, the degree of the hygrometer; the 3d, that 
of the thermometer; and the 4th gives the number of strikings 
per minute of the gold leaves. 
Experiment 1. in open Air. Experiment 2. in the Receiver. 
Time. Hygrom. Therm. Strik. Time. Hygrom, Therm.  Strik. 
Hour. Min. Hour. Min. 
3 41 534 5 Leora hy WA HSS * 745 
B.S 41% Idem Idem ! 410 Idem Idem Idem 
3 10 Idem Jd Id 4:15 aid Id Id 
Sis Id Id Td 430 Id Id Id 
3 45 Al 54 dd 6°15 *'a2is., «58 3 
4 Id ue Id I} 
Experiment 
