THKORY OF GALVANISM. 
'i04 
Excii.tinent of this happens, they destroy the effect of each other. I was < 
Tiicitv, and 3ware of that effect, and endeavoured to prevent it as much i 
piienoiiieiia as I could, ^ 
of /the electric t j i i 
colimin. ^ understood, therefore, the benefit resulting from that un- 
connected disk of paper, as producing a distance between the 
metallic papers ; but I have only found its great effect by 
making use of it, I have placed a piece of thick paper be- 
tween the pairs of one of my columns : while 1 mounted it 
I saw that these additional pieces prevented the mutual contact 
of the pieces of coppered paper ; and when it was mounted, 
I was astonished to find that the electromotion had more than 
doubled in that column. Such is one of the great improve- 
ments made by Mr. Singer in the electric column, which be 
is so modest as not to point out himself, 
I come to the second improvement, no less important, made 
by the same distinguished experimental philosopher, in the 
electric column, which has also much increased its effect : it 
is the more necessary to mention it, that he does not speak of 
it himself; and it therefore is known only to those who have 
attended his lectures ; besides, had he only mentioned it in his 
paper, the mere description would not have conveyed the idea 
of its effect. , 
Mr. Singer has divided his column into parts of 100 pairs 
each, inclosed in glass tubes having bmss caps fixed with sealing 
wax at their extremities : brass screws, having a ring outside, 
pass through the centre of the caps, and serve, both to com- 
press sufficiently the pairs of disks in the tubes, and to pro- 
duce the communication between those parts of the column, 
as Ji had done in connecting together my chaplets. 
Such is the other improvement made by Mr. Singer in the I' 
coiumai ; but, as I have said above, had he only explained it I' 
as a part of the construction of his apparatus, the increase of I 
electiiomotion which it produces had probably been understood I* 
by viery few of your readers. The cause of that increase is, I' 
in it' self,' a very interesting object of natural philosophy, as it f 
is c< mnected with some important physical phenomena ; but I' 
for I 
