REVERSIBLE AND IRREVERSIBLE SYSTEMS UNDER INFLUENCE OF LIGHT. 359 
in (7) 17 millims., in (8) 19 millims., in (9) 17 millims., average = 17 millims. = 
19xl0 -9 ampere = lG^xlO -6 volt (at intensity of the arc = 11’5 centims.); for 
light intensity = 12'1 centims., the average deflection = 17*9 millims. The law of 
intensity : 
36 2 x 17'9 = 23'2 x 10 3 and 26 2 x 34'5 = 23‘3 x 10 :1 if not corrected, 
37 2 x 17'9 = 24'5 x IQ 3 and 26 2 x 36’5 = 24’7 x 10 3 if corrected. 
Plate N 4 of June 6, 1903 (4 Curves), New Carbons (“Imperial Crown”), Table I. 
The same combination from June 3 was taken. Experimental data, Plate N4, 
Table I. The deflection obtained at a distance of 26 centims. is: in (1) 55 millims., 
in (2) 54 millims. = average 54'5 millims. = 63'9x 10 -9 ampere = 54'4x 10~ 6 volt. 
The deflection obtained at a distance of 36 centims. is: in (3) 28 millims., in 
(4) 28 millims., average = 28 millims. = 32 - 8 x 10~ 9 ampere = 27‘9 x 10~ 6 volt. We 
get for the law of intensity : 36 2 x 28 = 36'3 x 1 0 3 and 26 2 x 54'5 = 368 x 10 3 . 
Plate of June 8, 1903 (4 Curves) ( 3rd Curve interrupted, Plate No), Table 1. 
The same system from June 3, the same carbons as on June 6 ; the E.M.F. in the 
dark = 93xl0 -6 volt. Deflections obtained at 36 centims. distance were: in (1) 
29 millims., in (2) 29 millims., in (3) interrupted, in (4) 26 to 27 millims. = average 
28'2 millims. = 33 x 10~ 9 ampere = 28T x 10~ 6 volt. 
Comparing tbe tables of the 4th and 5t-h of June with that of the 6th of June, and 
8th, 11th, 18th, and 19th of June, which will subsequently be dealt with : — 
Date 
June, 
1903. 
Distance 
of arc 
from 
quartz 
vessel. 
Dis¬ 
tance of 
quartz 
vessel 
from 
quartz 
window. 
Deflection 
of 
Nalder 
Nl. 
Intensity 
of light 
in deflec¬ 
tions of 
Nalder 
N2 = A. 
Cali¬ 
bration 
of 
Nalder 
N2, 
B. 
Cali¬ 
bration 
of 
Nalder 
Nl. 
Intensity 
of light 
A/B. 
Deflection 
of Nalder 
N1 for the 
intensity 
of light 
0-586 = A/B. 
centims. 
centims. 
millims. 
millims. 
4 
37 
8 { 
18 
19 • 7 (corr.) 
11-6 
19-8 
17-4 
0-586j 
18 
19 7 (corr.) 
5 
36 (7) 
8 
17 
11-5 
19-8 
17-4 
0-581 
17 
New 
carbons, 
“ Imperial 
Crown ” _ 
r 6 
36 
8-5 
28 
12-7 
19-8 
17-4 
0-641 
25-6 
> 
36 
8-5 
28-2 
13-5 
19-8 
17-4 
0-682 
24-2 
In 
36 (7) 
8 -5 
32 
12-9 
19-8 
17-4 
0-651 
25-2 
This table shows that the different composition of the carbons alone can considerably 
vary the intensity of their light and influence the value of the E.M.F. produced. 
