at Low Pressures. 
255 
Table III. 
Pressure 0*98 mm. 
Mag. Field 45 -1 
Pressure 1-85 mm. 
Mag. Field 45-1 
Hall Effect (Volts) 
Current 
Hall Effect (Volts) 
Current 
0-806 
6-65 x 10- 4 
0-38 
2-16 x 10- 3 
0-791 
8-54 „ 
0-36 
2-79 „ 
0-40 
4-41 „ 
0-828 
13-20 „ 
0-36 
5-31 „ 
0-814 
20-60 „ 
0-40 
7-11 „ 
Mean 0*810 
Mean 0*38 
Table IV. gives the results obtained for the Hall effect at 
different pressures from 2 90 to 0'266 mms. 
These results show that the Hall effect varies inversely as the 
pressure. If Z is the transverse fall of potential or Hall effect, 
p the pressure in millims. of mercury, and H the magnetic field, 
then 
^ = 0-0248 —. 
V 
Table IV. 
Pressure 
(. V ) 
Hall Effect 
(Volts per cm.) 
Mag. Field 
Zp 
H 
2-91 
0-356 
45-2 
2-29 x 
io - 2 
2-23 
0-475 
45-8 
2-32 
1-85 
0-597 
46-3 
2-38 
>> 
1-22 
0-915 
44-7 
2-49 
}» 
0-983 
1-20 
46-3 
2-54 
5) 
0-650 
1-85 
46-8 
2-56 
J5 
0-508 
2-42 
46-3 
2-76 
J) 
0-333 
3-24 
46-8 
2-31 
J> 
0-266 
4-60 
46-4 
2-64 
JJ 
Mean 2-48 
