( 673 ) 
TABLE IV. 
Cobalt I at ordinary temperature. 
B e (gauss) 1' (cm. of the scale) calculated zero 
4025 17.16 76.73 
8050 38.14 77.47 
12075 50.48 78.96 
19560 53.24 78.37 
23340 53.29 78.18 
25650 53.30 78.63 
the observed 
zero was 
not 
recorded 
Cobalt I at temperature of solidifying hydrogen (14°.3 K.) 
4025 
8050 
15820 
19560 
21800 
13.5 
32.59 
54.33 
54.43 
23340 54.45 
24760 54.46 
77.62 
78.84 
81.93 observed zero 
81.40 78.26 
81.16 
81.02 
From this it appears that asymmetric disturbing forces affect the 
main phenomenon. It is probable that we are here dealing with 
phenomena of crystal magnetism arising from the fact that in the 
small ellipsoid the crystalline elements of the cobalt are not suffi¬ 
ciently numerous to realize isotropy by compensation. The magnitude 
and sign of these subsidiary actions are independent of the main 
phenomenon, and they can even be of opposite effect for both azimuths 
of the electromagnet; they can become of very great importance if 
the substance possesses a more or less pronounced magnetic plane, 
and the, example of pyrrhotine shows us that their influence becomes 
greater at lower temperatures. Further, the law of approach to 
saturation in cobalt which differs from that which holds for the 
other substances is consistent with the existence of strongly developed 
magneto-crystalline phenomena J ). 
These experiments were repeated with a second cobalt ellipsoid, 
and the same asymmetric action, but somewhat weaker, was observed. 
But in this case a disturbance of another nature was encountered, 
which shows how concomitant disturbing phenomena may affect the 
measurement of magnetization: the magnetization at low temperature 
was now found to be apparently smaller than at ordinary temperature. 
The following table contains an extract from the results obtained 
with this ellipsoid. 
9 P. Weiss, Arch. 
Sc. phys. 
it. fevrier 1910, Journ. de phys. 
s 1910. 
