Wg30o K 4 wy! 
—, but a greater value for —— at the tempe- 
W273° K Wo 
rature of liquid air. At higher temperatures there is also agreement 
between BrAKE’s values for the latter ratio and mine. 
The maximum in the isopedals found by Brake to lie at 36600 
gauss at the temperature 7’ = 99° K. and which, for lower tempe- 
ratures, ought to be found at lower fields, was not observed in the 
present experiments. 
mean value for - 
In the weaker fields the isotherms are convex towards the axis 
of abscissae ; from 12 Kilogauss upwards they become straight. For 
H > 12000 the relationship 
r 
a + b vce Tite ieee 
holds, where a and 5 are constants, while, at lower temperatures 
EPE ON Ei ae EN 
to a first approximation. The following Table shows to what degree 
of approximation this relationship holds. 
TABLE III. 
a for Bj dr 
EEE 
T Abs. | Fale. 
| 
170 1.94 | 1.95 
139.5 4.2 4.5 
90 18.3 aye 
72 1.7 | 210 
20 117.5 | 114 
15 121 131 
Even at the boiling point of oxygen 5 is already clearly negative 
— 26.5). As the temperature falls the absolute value of 4  increa- 
ses rapidly, and at hydrogen temperatures it reaches the value — 110. 
§ 8. The Hau effect and the increase of resistance of plates of 
compressed electrolytic bismuth. Tables IV and V contain the results 
of measurements made at ordinary temperature and at two liquid 
oxygen temperatures with the plates Bi, and Bij. Mè is the Harr- 
