ELECTRIC DISCHARGE WITH THE CHLORIDE OP SILVER BATTERY. 499 
Tube 150. COo. 
4G40 cells at pressures 0"45 m.m. and 0'25 man.; in the first case battery full potential 
242 divisions, in the second 213 divisions. 
In the first series, at both pressures, the positive was connected with No. 1 ring; 
in the second, the negative was connected with No. 1 ring. No. 17 ring and the 
opposite pole of the battery to earth. 
Pressure 0’45 millimetre. 
Potential. 
Pressure 0-25 millimetre. 
Potential. 
Distance 
between 
17th and the 
Ring. 
Positive to No. 1. 
Negative to No. 1. 
Positive to No. 1. 
Negative to No. 1. 
following 
rings. 
Divs. 
Cells. 
Ratio. 
Divs. 
Cells. 
Ratio. 
Divs. 
Cells. 
Ratio. 
Divs. 
Cells. 
Ratio. 
Ratio. 
1 
85 
1629 
1-77 
61 
1169 
1016 
82 
1786 
1-34 
74 
1612 
12-34 
16-44 
3 
78 
1496 
1-62 
34 
652 
5-66 
77 
1677 
1-26 
12 
261 
2-00 
14-44 
5 
73 
1400 
1-52 
30 
575 
5-00 
73 
1590 
1-20 
21 
457 
3-50 
12-37 
7 
68 
1304 
1-42 
27 
518 
4-50 
71 
1546 
1-16 
10 
218 
1-67 
10-24 
9 
62 
1189 
1-29 
21 
402 
3-50 
67 
1460 
1-10 
16 
348 
2-67 
8-24 
11 
58 
1112 
1-21 
23 
441 
3-83 
64 
1394 
1-05 
21 
457 
3-50 
6-22 
13 
52 
997 
1-09 
14 
268 
2-33 
59 
1285 
0-97 
8 
174 
1-33 
4-06 
15 
48 
920 
1-00 
7 
134 
116 
59 
1285 
0-97 
6 
131 
1-00 
2-00 
16 
48 
920 
1-00 
6 
115 
1-00 
61 
1328 
1-00 
6 
131 
1-00 
1-00 
17 
0 
0 
o-oo 
0 
0 
o-oo 
0 
0 
o-oo 
0 
0 
o-oo 
o-oo 
The results are shown in the diagram, fig. 22. 
The foregoing experiments “ show clearly,” as Professor Stokes has pointed out to 
us, “that at high exhaustions nearly the whole of the energy is spent in the passage 
of the discharge between the gas and the negative electrode. It seems pretty clear 
that the electric potential energy is converted into kinetic energy. 
“ There appears to be no such difficulty as regards the positive. The increase of 
change of potential near the positive at moderate exhaustions seems fully accounted 
for by the contraction of the path of the discharge, as the electricity issues at first 
from little more than a mere point, and the path at first lies within an approximately 
conical boundary. 
“ The experiments bear in an important manner on the theoretical height of the 
aurora. It appeal’s that at high exhaustions gases offer little obstacle to the passage 
of electricity ; only there must be matter enough to carry it. On the whole the 
experiments tend to considerably increase the theoretical height, which accords with 
observation, so far as such observations can be trusted. 
“How far the first issue of electricity from a charged cirrus cloud resembles the 
issue from a metallic electrode is a matter of speculation.” 
