DISCHARGE OF NEGATIVE ELECTRICITY FROM HOT PLATINUM. 
2G3 
4. Variation of the Current with the Time. 
In the previous paper the variation of the current with the time was considered in 
detail, and it was shown that the results obtained could be explained by supposing 
that the leak depended on the amount of hydrogen in the wire, and that a 
considerable time was required for the hydrogen in the wire to get into equilibrium 
with that outside. For example, it was shown that on diminishing the pressure at 
constant temperature the leak fell slowly. The previous results were obtained with 
new wires. With wires which have been heated in hydrogen at high pressures the 
variation with the time is similar to that with new wires, but the leak does not fall 
below a certain value, however much the pressure is reduced. The following table 
contains a series of observations on a wire at 1310° C. in hydrogen. The wire was 
left cold during 1 each night. 
o o 
Time. 
Current. 
Potential 
difference. 
Pressure. 
Days. 
Minutes. 
ampere 
TOlts 
millims. of Hg. 
0 
8-6 x IO - 5 
200 
195 
0 < 
10 
4-4x 10- 5 
200 
195 
1 
35 
4-5 x10- 5 
200 
195 
100 
5-2 x 10" 6 
200 
195 
r 
0 
8■4 x10^ 5 
784 
784 
10 
2-8 x10“ 5 
784 
784 
1 I 
50 
9-5 x lO-o 
784 
784 
100 
2-8 x10“ 6 
784 
784 
r 
0 
3-5 x 10“ 6 
784 
784 
100 
l-5x 10-6 
784 
784 
9 j 
120 
1 -5 x10-8 
784 
784 
A *< 
130 
7-Ox 10“ 7 
385 
385 
180 
7-4x 10“ 7 
385 
385 
220 
1-3 x10“ 7 
30 
23 
. 
r 
0 
7-5 x10“ 7 
30 
23 
3 \ 
60 
1•9 x10~ 7 
30 
23 
200 
3-4x10“ 7 
30 
0-84 
r 
0 
6-2 x10- 7 
20 
0-84 
4 \ 
60 
5-4x10- 7 
20 
0-84 
1 
120 
5-6 x 10- 7 
20 
0.-84 
r 
0 
4-4 x10“ 7 
20 
0-24 
5 < 
60 
3-5 x10“ 7 
20 
0-24 
1 
180 
3-5 x10- 7 
20 
0-24 
300 
3-6 x10“ 7 
20 
o-ooo 
6 J 
0 
3•2 x 40- 7 
20 
0-006 
6 1 
60 
3-6 x10- 7 
20 
0-006 
f 
0 
3-8 x 10-8 
20 
1-64 
9 \ 
60 
3-7 x 10- 7 
20 
1-64 
1 
L 
120 
5-Ox 10- 7 
40 
1-64 
The wire was left cold between the seventh and tenth days. After several weeks’ 
further experimenting with this wire at various temperatures and pressures, the leak 
at the same temperature as that at which the above results were obtained was 
