392 Mr Wilson, The Hall Effect in Oases 
Table II. 
The Electric Intensity in the Uniform Positive Column 
in Hydrogen. 
Pressure. 
Electric Intensity. 
X 
(v) 
<*) 
s/p 
0*25 mms. 
13 - 9 volts per cm. 
27-8 
0-48 
18-8 
27-2 
0-56 
21*6 
28*9 
0-60 
21-9 
28-3 
1-05 
28-5 
27-8 
1-27 
31*9 
28-4 
1*36 
32-3 
27-7 
Mean 28*0 
The pressures are expressed in millimetres of mercury and the 
Hall Effects and Electric Intensities in Volts per centimetre. 
Above one millimetre pressure satisfactory measurements of the 
Hall Effect were not obtained. 
The above results show that the Hall Effect and Electric 
Intensity in hydrogen at pressures below one millimetre follow the 
same laws as in air. The Hall Effect is given by the equation 
H 
Z = 2’05 x 10 -2 — , and the electric intensity by the equation 
P 
X = 28 Vp. The corresponding equations found for air in the 
H — 
previous paper were Z = 2"48 x 10“ 2 — , and X = 344) Vp. 
Tables III. and IV. give the results obtained in oxygen. 
Table III. 
The Hall Effect in the Uniform Positive Column in Oxygen. 
Pressure. 
Hall Effect. 
Magnetic Field. 
Zp 
ip) 
(Z) 
(H) 
H 
0*21 
0-802 
42-6 
3-95 x 10- : 
0-32 
0-463 
43-1 
3-43 „ 
0-40 
0-399 
42-6 
3-74 „ 
0*48 
0-348 
43-1 
3-83 „ 
0-83 
0-207 
43-1 
3-98 „ 
Mean 379 x 10~ 3 
