12 
PROF. 0. W. RICHARDSON ON THE EMISSION OF ELECTRONS 
be of importance relating to the different series of observations, are set forth in the 
following table and remarks :— 
Table I.—COCL. 
Number of 
series. 
Mark indicating 
experimental 
points of series 
on curves. 
Initial pressure, 
millimetres of 
Hg. 
Final pressure, 
millimetres of 
Hg. 
Displacement in 
volts from volt¬ 
meter readings to 
scale position in 
fig. 4. 
Date. 
I. 
X 
0-0015 
0-016 
+ 1-00 
3/8/1916 
II. 
o 
0-004 
0-020 
+ 1-45 
25/7/1916 
III. 
k 
0-001 
0-011 
+ 0-55 
25/9/1916 
IV. 
0 
0-003 
0-087 
+ 3-30 
2/11/1916 
V. 
© 
0-002 
0-012 
+ 2-62 
3/11/1916 
VI. 
O 
0-001 
0-038 
16/9/1916 
(The numerals I., &c., and marks x , &c., are relevant to the data in figs. 3 and 5, as well as in fig. 4.) 
Remarks on each Series. 
I. x.—Generator adjusted at the beginning of the experiment and later. The 
effect rose slowly after each adjustment. Chemical saturation current: minimum 
value 45 divisions per minute with cap. 0-01 mfd., maximum 200 divisions per 
minute, cap. 0 *04 mfd. Saturation photo-electric current, 64 divisions per 
minute with 0 *04 mfd. Maximum chemical and photo-electric effects thus of 
same order of magnitude. Gas was pumped out in the middle of these experi¬ 
ments without affecting the results. These observations were very consistent. 
The only apparent defect was a small insulation leak which had to be allowed for. 
The slight variability of this makes the point of intersection of the curve (I., 
fig. 3) and the voltage axis a little doubtful. A test at the end of the series with 
the mercury line 4355 gave 252 divisions per minute and with the green line 
0 -7 division per minute, the capacity being 0-01 in each case. 
II. O .—Generator adjusted at the beginning and again at the middle of the series. 
Effect rose before and after adjustment. Maximum chemical saturation current, 
160 divisions per minute, minimum 42 per minute ; X 4355 photo-electric satura¬ 
tion current, 160 divisions per minute ; all with capacity 0 -02 mfd. Six drops per 
minute, diameter of drops 3 to 4 mm . 
HI- —Generator not adjusted in these experiments. Chemical effect dropped 
steadily most of the time, then rose a bit towards the end and fell oh again. 
Chemical saturation current: maximum 28 divisions in 60 seconds, capacity 
0 -03 mfd. ; minimum 37 per minute, capacity 0 -01 mfd. X 4355 photo-electric 
saturation, 53 per minute with 0-03 mfd. capacity. Four drops in 90 seconds. 
