995 
be made between hydrogen and oxygen temperatures. These portions 
of the curves are therefore indicated by dotted lines. With Ag and 
Au the Harreoefficient increases as the temperature falls. This 
increase takes place chiefly in the temperature region 20° < 7’'< 77°K. 
In the hydrogen region, 20°.3 > 7’>14°.5, R is constant within 
the limits of accuracy. A very small diminution of the Harrcoeffi- 
cient is exhibited by the alloy (Aw-Ag); with 2°/, Ag at low tem- 
peratures. At low temperatures alloys with more than 2°/, of Ag 
show a distinct diminution in the Har effect, which is greatest for 
alloys of medium concentrations. Thus alloy HI with 30 °/, Ag gives 
aoe = (0.64. With Aw and Ag the ratio aa differs but very little 
Rego 22900 
from 1, while with alloys of medium concentration it differs consi- 
derably from 1. Of the alloys with a large percentage of Au, a 
distinct diminution of the Harreffect at low temperatures is already 
exhibited by alloy VI, with 2°/, of Au. | 
_ In fig. 6 is shown the relation between the Lepuc constant 
R : 
Dr =-— and the atomic percentage of Ag at 7’= 290° K. and 
w 
T=90° K. This constant is the tangent of the angle of rotation of 
the equipotential lines in unit field. The curves are of the same 
nature as the conductivity-silver percentage diagrams; at lower tem- 
peratures they become steeper. When two per cent of Aw is dis- 
solved in Ag, Dr at T=20° 3K. sinks from 720 <10 "to85 K 10%. 
It is worth noting that with alloys of medium concentration Dy is 
approximately constant throughout the whole temperature region 
290° > T > 14°. 5; this holds for 10.7 < « < 90.9 that is to say, for 
alloys in which the percentage of neither component is less than 10. 
With alloys which may be regarded as dilute solutions, hence for 
0<a#<11 and 90 << 100, as a rule A is, to a first approximation, a 
. . * e wT ryy . 2 i ) 7 
linear function of the temperature quotient — (7’= 290° k, 90° K., 
Ww 
Wy 
