( 351 ) 
must rather describe the difference between the values found now 
and formerly to an uncertainty in the knowledge of the resistance 
in the circuit of the Harr-currert®, which is required for the 
calculation of RA, For, as the variations of this resistance appeared 
only after some time, the resistance was not measured, during the 
experiments of the first determinations in § 3. With the determina- 
tions now published the resistance was measured twice during the 
experiment and was found to be constant. Therefore we retain the 
value 11,0 for 10° C; 
The value at — 90° C. for a magnetic field of 4400 is found by 
interpolation to be 17,1 and is for the same reason not quite certain. 
C 
Tobe | R 5e C' 
922 salt 21.0 11,0 11,0 
EE AN AN oh 17,0 12,7 
91 41,4 34,2 22,2 
5) See § 3. 
Proceedings Royal Acad, Amsterdam. Vol. II. 
