366 DR. MEYER WILDERMAN ON THE CHEMICAL STATICS AND DYNAMICS OF 
photograph the last 3 or 4 milium of the ends of the deduction period so as to avoid 
the danger of several lines coinciding on the photographic sheet, but I waited, after 
the screen of the chronograph was shut, some tune till it could be assumed that the 
deduction was complete. 
The deflections obtained with N6 and 7, with the intensity of acetylene 
= 39 millims., were : 43'5 and 44'5 millims., average = 44 millims. = 46 8 x 10 
ampere = 41‘0 x 10 -6 volt. The curve m N6 was allowed to return to its E.M.F. m 
the dark, in N7 the last few millimetres of the end of the deduction period were not 
photographed. The deflections obtained with N8 and 9, with the intensity of 
acetylene = 28-5 millims., were: 32'5 and 31 millims., average = 31 *8 millims. 
= 33 - 8 x 10“ 9 ampere = 29'6 x 1(T 6 volt; the last 2j to 3 millims. were not 
photographed, but, as before, I waited till the deduction period must have become 
complete. 
From the data given in the above table we get again the law of intensity— 
81-6 : 71 = 1T5 ; 44 : 39 = 1T3 ; 3D8 : 28'5 = 1T2. 
The above data obtained for light of the same intensity (and composition) on 
repetition of the experiment: 84, 81, 82, 80, 81 millims. ; 43‘5 and 44'5 millims. ; 
32'5 and 31 millims. give a sufficient illustration that during the time the above 
curves were taken, and with light of such small intensity, which cannot affect 
essentially the composition of the electrode exposed to the same, the same deflection 
is obtained, and this shows that the chemical potential and solution pressure of the 
same plates remain constant. The cell is reversible, as it follows from the considera¬ 
tion of the reactions going on in it, and from the course of the above curves, the 
induction and deduction periods of which show no polarisation, while the system 
always returns to its former state, whenever on removal of the light we allow the 
deduction period to become complete. It is constant, as is shown by the shape of the 
parts of the curves giving the induction and deduction periods, from the straight 
line c—c, obtained in light, parallel to the line a-b in the dark, and from the fact that 
on repetition of the experiment the same maximum deflection is obtained. 
(3) Plate 13 (b) of July 29, 1903, contains 13 Curves, Table III. —The same 
system was investigated a few hours later, first with acetylene, then with the arc. 
Acetylene light and coloured screens (curves N\, 2, 3, 4, 5, 6, 7), Experimental 
data, see Table III., pp. 392-393. 
In curve N1 the total acetylene light as before was used, at a distance =116 
centims. ; the deflection was 80 millims. The next curves, M2, 3, 4, 5, were taken 
with the red screen : N2 and 3 at a distance of the acetylene light from the quartz 
vessel =116 centims., N4 at a distance of 80 centims., N5 at a distance of 57 centims. 
The maximum constant deflections obtained for N2 and 3 were 28 and 29 millims. 
= average 28'5 millims. = 30'3x 10 -9 ampere = 26‘6 x 10 6 volt in N4 = 60 millims. 
= 63'7 x 10 -9 ampere = 55-9 x 10 -6 volt, in N5 it was about 3 millims. greater 
than could be got on the photographic paper (115 millims.), since the photographed 
