ME. W. CROOKES ON EEPULSION RESULTING FROM RADIATION. 
335 
No one moved during the experiment, and the room was in perfect darkness (except 
from the candle) and was of a uniform temperature. 
Each recorded observation is the mean of three or four. I did not carry the series 
beyond 35 feet, as that was the greatest distance I could get in my laboratory. 
Distance between 
standard candle 
and pith bar of 
instrument. 
Movement of luminous index on millimetre- 
scale, 5 feet 6 inches from the hanging mirror, 
in millimetres. 
With no screen 
interposed. 
With a glass screen, 
2 millims. thick, 
interposed. 
feet. 
millims. 
millims. 
35 
9-0 
6-0 
34 
13-0 
8-0 
33 
14-0 
9‘5 
32 
11-5 
7*5 
31 
13-5 
9-0 
30 
13-5 
8-5 
29 
16-0 
10-5 
28 
14-0 
9-0 
27 
16-5 
11-0 
26 
23-5 
15-5 
25 
18-0 
11-5 
24 
19'5 
13-0 
23 
23-5 
15-5 
22 
23*5 
15-0 
21 
26-0 
17-5 
20 
28-5 
19-0 
19*5 
31-0 
20-5 
19 
32-5 
21-5 
18-5 
33-0 
22-0 
18 
37-5 
24-5 
17-5 
39-5 
26-5 
17 
43-0 
28-5 
16-5 
43*5 
28-5 
16 
45-5 
30-5 
15-5 
50-5 
34-0 
15 
52-5 
35-0 
14-5 
56-0 
37-5 
14 
63-5 
42-5 
13-5 
66-0 
44-5 
13 
71-0 
47-5 
12-5 
78-0 
51-5 
12 
. 82-5 
54-0 
11-5 
87*5 
58-5 
11 
96-5 
64-0 
10-5 
108-5 
72-0 
10 
114-5 
77-0 
9-5 
133-0 
89-5 
9 
147-0 
97-5 
8-5 
165-0 
111-5 
S 
190-0 
125-0 
7-5 
210-0 
138-0 
7 
244-0 
162-5 
6*5 
279-5 
187-0 
6 
325-0 
218-0 
1 could not take measurements with the candle nearer than 6 feet, as the index went 
3 a 2 
