94 
PHYSICS: K.-L. YEN 
tive mobility also remains absolutely normal with 5668 volt/cm. or X/p — 
12.15. Thus it may be concluded that the law Up = constant, where 
U = mobility and p — pressure in mm. mercury, is verified for hydrogen 
up to these limits. 
Besides the normal positive and negative ions the existence of free negative 
'electrons in hydrogen was proved. These electrons existed in abundance 
when the gas was freshly prepared and disappeared entirely after the gas had 
remained in the ionization chamber for about six or eight hours. The dis- 
appearance of the electrons might conceivably be the result either of their 
fast dissipation into the walls of the chamb*er or of their ready formation 
of negative ions with the neutral molecules of either hydrogen or the im- 
purities from the sealing wax that had evaporated into the chamber in the 
meantime. 
TABLE 
u+ 
U- 
x+ 
X- 
P 
K- 
R 
60 cycles 
5.28 
77.8 
748 
5.21 
5.50 
8.80 
25.0 
16.5 
746 
5.41 
8.65 
1.52 
6.60 
11.19 
20.0 
13.0 
600 
5.22 
8.80 
1.62 
8.95 
13.28 
29.5 
24.0 
498 
5.85 
8.70 
1.48 
13.90 
22.00 
19.8 
11.5 
300 
5.49 
8.69 
1.58 
22.91 
31.06 
16.5 
99.0 
198 
5.95 
8.15 
1.34 
9.26 
28.0 
746 
9.26 
Mean 
5.52 
8.71 
1.57 
X - /P Max. = 12.15, Min. = 0.38. X + /P Max. = 14.45, Min. = 0.66. 
An effort was made to search for the two other kinds of negative ions which 
Haines claimed to have found. 7 And as no trace of these other ions could be 
found it was thought that the disposition of the apparatus employed might 
not have been sufficiently adequate for their detection. Consequently it 
was considered desirable to repeat Haines' experiment in order to rectify the 
present method. Thus Haines' experimental conditions were reproduced as 
exactly as possible according to his descriptions with the expectation of 
obtaining similar results. 
The results of this operation are shown in table 3. 
These results agree with those obtained in the employment of the high 
frequency high potential field in showing that no such intermediate negative 
ions existed. This, together with a careful study of Haines' curves, led to the 
conclusion that in so far as experimental results are concerned there is not a 
scrap of evidence, either in Haines' results or in those obtained in the present 
experiment, of these other species of negative ions which were claimed to 
exist by Haines. 
