1904-5.] Opacity of Aluminium Foil to Ions from a Flame. 905 
2°. Flame lit for 20 Minutes before Readings taken. 
(Plate cd to Earth.) 
Time in Minutes. 
Reading. 
Leak per 5 Minutes. 
0 
26-2 
5 
28*3 
2’1 
10 
30-7 
2-4 
15 
32-8 
2'1 
Average leak per 5 minutes, 2 '2. 
3°. Flame lit {already fur 35 Minutes). 
(Plate cd to 360 volts.) 
Time in Minutes. 
Reading. 
Leak per 5 Minutes. 
0 
33-2 
5 
35-4 
2'2 
10 
377 
2-3 
15 
39-9 
2-2 
Average leak per 5 minutes, 2*2. 
1°. Flame unlit. 
(Plate cd to Earth.) 
Time in Minutes. 
Reading. 
Leak per 5 Minutes. 
0 
22-8 
5 
24-7 
1*9 
10 
267 
2-0 
15 
28-7 
2’0 
Average leak per 5 minutes, 2’0. 
