electrical phenomena exhibited in vacuo. 
75 
EXPLANATION OF THE PLATE. 
Plate V. 
A. The tube, of the usual diameter. 
B. The wire for communicating electricity. 
E. A small cylinder of metallic foil, to place as a cap on 
tubes not having the wire B, to make a coated surface. 
C. The surface of the quicksilver, or fused tin. 
D. The part of the tube to be exhausted by the stop-cock 
F, after being filled by means of the same stop-cock, when 
necessary, with hydrogene. 
G. The moveable tube connected with the air-pump. 
It is evident, that by introducing more mercury, the leg D 
may be filled with mercury, and the stop-cock closed upon it, 
so as to leave only a torricellian vacuum in the tube, in which 
the mercury may be boiled. I have found that the experiment 
tried in this way, offers no difference of result. 
