of the Active Deposit of Acth 
741 
the brass plates, 1*5 cms. apart, were fixed parallel to one 
another and connected to the terminals of a battery as before ; 
and their distance from the actinium could be varied as 
required. 
Two series of observations were made, at 76 cm. and 2 mms. 
pressure, for different distances of the plates from the 
actinium. After an exposure of about two hours the plates 
were removed and their activities compared by means of an 
u, ray electroscope. 
The numerical results are collected in Table II., and the 
variation with distance of the ratio of the activity of the 
negative to that of the positive plate is reproduced graphically 
in fig. 4 (p. 742). 
Table II. 
Distance from 
Actinium. 
Activity in Arbitrary Units. 
Ratio. 
— ve 
+ve 
Negative plate. 
Pressure. 
300 
250 
220 
200 
117 
100 
14 
10 
Positive plate. 
76 cms. 
27 
3-0 
3-1 
4-2 
5-4 
7 "7 
5-9 
4-3 
110 
83 
72 
48 
22 
13 
2-4 
2-3 
•4 
•9 ......... 
1-4 
1 2-2 
27 
4-4 
50 
2 mms. 
•2 
Pressure. 
7-9 
1-6 
1-5 
1-3 
1-0 
49 
4-8 
9-6 
220 
10 
7-4 
14-1 
22-0 
22 
4-2 
An inspection of the second and third columns of Table II. 
shows that at 76 cms. pressure, whereas the active matter 
deposited on the negative plate decreases as the distance of 
the plate from the actinium is increased, the amount obtained 
on the positive plate increases till a distance 2*7 cms. from the 
Phil Mag. S. 6. Vol. 15. No. 90. June 1908. 3 D 
