364 DR. MEYER WILDERMAN ON THE CHEMICAL STATICS AND DYNAMICS OF 
The law of intensity : 37 2 x 55'5 = 76 x 10'’ and 50“ x 32'5 = 81 x 10 ”, i.e., the E.M.F. 
is directly proportional to the intensity of light. 
Curves N 5 and N6 give the deflections obtained with the red screen, curves N7 
and N8 with the blue screen, curves N9 and NlO with the yellow-green screen, all 
at a distance of the arc from quartz vessel =37 centims. The ratio of the deflections 
in millimetres of the white light : blue : yellow-green : red = 54’5 (corr. 55'5 millims.) : 
13 millims. : 5'5 millims. : 3-5 millims., or in per cent, of the total light without 
screen = 100 per cent. : 23-4 per cent. : 9-9 per cent. : 6*3 per cent. This shows in 
the first instance that the so-called “ actinic ” rays act most. Calculating now the 
thermo E.M.F. at a distance of 37 centims. we get:— 
If cItt/cIt is put, according to Gockel, = 0-00014 volt, then, since the rise of 
temperature was 
(0°-03 to 0°'045)x 27 2 x 19-8 x 15*5 
37 2 x 12-7 x 16-7 
0°-023 to 0°-035 G, 
the thermo E.M.F. = (3'2 to 4 - 8) . 1(T 6 volt; since the sensitiveness of Nalder Nl 
was 94-4 centims. per 1CT 6 ampere, we get the thermo E.M.F. on Nalder Nl = 3’5 
to 5-2 millims. for the total light, and = 2'5 to 3*8 millims. for the red screen, 
= 2’6 to 37 millims. for the yellow-green screen, = 2 '4 to 3'6 for the blue screen. 
The ratio of the total light : blue : yellow-green : red, at a constant temperature is 
thus: (93-1 to 95 4 per cent.) : (16‘9 to 19'2 per cent.) : (3‘4 to 5-6 per cent.) : (0 to 
1'8 per cent.). (No correction is made here for the absorption of light by the gelatine 
of the screens.) 
(2) On July 1, next day, the cell was no more constant, hut showed already 
a small 'polarisation of 3'6 millims., the above maximum deflection returning 
hack 3'5 millims., remaining only then constant. The maximum constant deflections 
on the drum at a distance of 37 centims. were : (53*5), 66T, 68*3, 70 3, 68‘3 millims. 
= average 68-'2 millims. = 72'5xl0 -9 ampere = 63-6xl0“ 6 volt. On shutting the 
screen, the spot of light first passed the zero deflection in the dark by 3’5 millims., 
returning 1 to zero deflection, where it remained constant. 
It follows from the above : (I) The sensitiveness of the plates remaining in the dark 
21 hours increased from about 55 millims. to about 68 millims. (2) The current 
passing in light from the plate in the dark to the plate in light, the AgCl of the 
plate in light, or the upper surface of the same, evidently transforms into Ag, while 
on the plate in the dark new AgCl was formed ; the system thus transformed on the 
previous day into (Ag in light, CINa solution, Ag-ClAg in dark). A direct investi¬ 
gation of a similar system (Ag in light, BrNa solution, Ag-BrAg in dark) showed that 
such systems form inconstant cells and show polarisation. An analysis of the 
reactions going on in such systems shows also that this must be the case. By the 
action of CL upon this system the system is reversed to the original combination, the 
formed Ag transforming back into AgCl, and the constant cell is again obtained. 
