448 
DE. W. ^lANSEEGH VARLEY ON THE PHOTO-ELECTPJC 
Table IV. 
j 
Potential to whicb 
^ zinc is charged 
in cells. 
(1 cell = 2-1 volts.) 
Current from zinc surface in 
electrometer scale divisions in 10 seconds in— 
IP. 
C0.2. 
Air. 
760 millims. 
76 millims. 
760 millims. 
76 millims. 
760 millims. 
4 
36 
81 
20 
32 
96 
45 
192 
39 
100 
73 
176 
128 
323 
89 
180 
92 
261 
176 
455 
112 i 
Notes .—The experiments were carried out in the small leak apparatus, the zinc 
electrode being situated 3'5 millims. behind the gauze. A P.I). of 1 volt between 
the electrometer quadrants corresponded to a deflection of 72 divisions. 
The standard apparatus indicated a sudden change in the intensity of the light of 
22 per cent, during the course of the last set of readings (C'O.;, at 76 millims. pressure), 
which has been corrected for in the table. 
The curves plotted from these observations are given in flg. 7. 
Table V. 
Current from zinc surface in electrometer scale di'\ 
'isions in 10 seconds in— 
Potential to which zinc is 
charged in cells. Air. 
(1 cell = 2-1 volts.) 
Ho. 
COo. 
30 millims. 
30 millims. 
30 millims. 
4 80 
67 
133 
20 ; 182 
144 
225 
60 1 253 
213 
295 
80 — 
277 
— 
100 339 
407 
396 
120 406 
665 
K O 
Oo t 1 
140 .502 
825 i 
Notes .—The experiments were carried out in the large leak apparatus, the zinc 
electrode being situated 2 millims. Ijeliind the gauze. A P.I). of 1 volt between the 
electrometer quadrants corresponded to a deflection of 66'4 divisions. A capacity of 
240 centims. was placed in parallel with the electrometer. A very intense.spark was 
used which kei^t constant to within 3 or 4 per cent., the various sets of observations 
being repeated a second time after the whole had been once taken. 
The results given iii this table are plotted in fig. 8. 
