658 
The magnetie change of resistance is much smaller for Birr parti- 
cularly so at low temperatures. 
Just as in the experiments in liquid hydrogen, +a H > 3000, RH 
becomes a linear function of the field 
READ os ae gee 
Following J. BrcQvereL *) we may regard the Harr-effect for 
bismuth as resulting from two components. One of these is propor- 
tional to the field, and was always negative for the plates (Bir, Biu) I 
used. The other is constant or, as one may say, saturated, for these 
plates from H = 3000 upwards. 
Within the temperature region 
Mkerk 
a’ can, to a first approximation, be satisfactorily represented by 
= Gee rel ets a ie ae ee 
The agreement for 7 = 90° & between observation and calculation 
from (3) with a’ = 20.6 and 6' == 39,3-< 10° for the plate Bir is 
exhibited in Table VII, while Table VIII shows how far the relation- 
ship (4) holds. 
TABLE MIL 
Linear variation of the HALL effect 
in strong fields for 
Birr at- 160" Kk; 
H | RH ops. ‚_ RH calc. 
| 3450 _ | 110.7X103| 110.4 >< 103 | 
| 5660 | 155.2 | 155.8 
7160 185.8 | 186.8 
| 8520 | 214.2 | 214.8 
| 9880 | 243.0 | 242.8 
| 11090 | 267.3 261.8 
| 12090 | 288.0 | 285,3 | 
The constant 6’ which gives the value of the second component 
of the effect in the state of saturation is commonly negative. Only 
for Bir at hydrogen temperatures does it become positive. With 
1) J, BucquereL: C. R. 154, 1795, 1912. 
