( 352 ) 
This however interferes little with the value of the following, in 
which for the sake of comparison besides the absolute temperatures 
C 
T and the corresponding values of & the values pare also given, 
where C has been chosen so as to make the value at 10° C. equal 
to 11,0. Further in the values C'7, where r represents the resistance 
of electrolytic bismuth in a field of 4400 C.G.S. units, taken from 
observations by FLEMING and Dewar), C' is likewise chosen to 
make the value 11,0 at 10° C. 
Fig. 3 gives a graphical representation of these numbers. It is 
evident that the Harr-coefficient increases much more rapidly than 
. C 
the resistance and a little more rapidly than it Hence no evidence 
of an approach towards a maximum can be found. 
In order to give a clearer view of the meaning of a HALL- 
coefficient 41,4 we will calculate the tangent of the angle through which 
the equipotential lines were turned in this experiment. For this it 
is necessary to know the resistance of the bismuth at — 182° C. in 
the magnetic field. As this resistance has not yet been measured 
for the plate, we take as a preliminary value 2,46.10°, taken from 
FLEMING and Dewar. We then find for the tangent the value 
0,740. 
For the sake of comparison a list is appended of the values of 
this tangent for some of the metals with the largest HaLt-coefficients, 
all of them for a magnetic field of 4400. 
Bismuth — 0,740 
Nickel — 0,085 
Antimony + 0,021 
Tellurium + 0,017 
Tron + 0,004 
As it may safely be assumed, that the Harr phenomenon has 
never been observed in a field of greater intensity, higher than 
20.000 C.G.S. units, it appears that the value 0,740 is the largest 
ever obtained. 
1) Proc. Roy. Soc. 60 p. 73, 1896, 
(January 24, 1900.) 
