Active Deposits of Radium, Thorium, and Actinium. 609 
The inner one R, 7 cms. long and *36 cm. diameter, acted 
as the rod upon which the active deposit was obtained, C the 
outside cylinder, 8'95 cms. long and 2*7 cms. diameter, being 
suspended by two platinum wires PP which were sealed into 
the glass vessel and connected to either pole o£ the battery 
as required. The ebonite ring E kept the outer cylinder 
steady, and the rod P was supplied with a guard-ring at 
each end, one of which fitted into a glass tube G, thus serving 
to keep the rod central within the cylinder C. 
These modifications were adopted so as to ensure a uniform 
electric field between the rod and cylinder, and also to render 
the problem more accessible to mathematical treatment, the 
areas of the rod and cylinder being not very different. 
With this arrangement experiments with the gases already 
mentioned were made, and the results obtained are collected 
in Table III. and reproduced graphically in figs. 5 and 6. 
Table III. 
Air. 
Sulphur Dioxide. 
i 
Sign of 
Electrode. 
| 
Pressure A ,. ., 
in mms. Actmt ^ 
Sign of 
Electrode. 
Pressure 
in mms. 
Activity. 
Positive. 
•115 108 
Positive. 
•302 
Ill 
.. 
•185 122 
j> 
1-120 
93 
•931 95 
,, 
i 
Negative. 
•115 
146 
Negative. 
•297 
148 
„ 
•260 
137 
„ 
•462 
184 
j> 
•902 211 
I 
» 
•970 
298 
Hye 
ROGEN. 
1 
Sign of 
Electrode. 
Pressure in 
mms. 
Activity. 
Positive. 
•084 
184 
,, 
•481 
200 
,, 
•828 
194 
Negative. 
•116 
•131 
•462 
212 
198 
192 
55 
•925 
•970 
1-080 
202 
239 
188 
