(3) 
67 percent Cd. solidify to homogeneous mixed crystals of the mercury 
type. Similarly all amalgams over 77 percent of cadmium solidify 
to homogeneous mixed crystals of the cadmium type. The behaviour 
of the 67—77 percent amalgams is more complicated. These all 
begin by depositing crystals of the Cadmium type up to 188°. The 
change: 
liquid C + mixed crystals D — mixed crystals HL, 
then takes place so that 67—75 percent amalgams (at the left of #) 
are converted into mixed crystals H + liquid C and solidify on further 
cooling to mixed crystals of the mercury type; on the other hand 
the 75—T77 percent amalgams completely solidify at 188° to a 
conglomerate of the crystals H and D of both types. 
The very important question in how far the limits of these 
two series of mixed crystals, which exist together at 188°, change 
as the temperature falls, has been 
studied electrically. A change in the 
composition of such limiting mixed 
£ crystals appears as a rule to take 
place but very gradually, so that 
d it was now, as in former instances, 
not possible to prove its existence by 
thermometric or dilatometric means. 
With this metallic mixture however, 
the opportunity presented itself of 
studying the matter by electrical 
methods. At the same time all the 
other percentages were investigated in 
order to obtain a first instance in 
Hg En, cawhich the electrical conduct of a metal- 
Fig. 2. lie alloy was known for all its various 
proportions. 
The EM F of alloys of every degree of concentration was measured 
in a solution of cadmium sulphate with a reversible mercury electrode 
as positive pole at temperatures of 25°—75°. 
If we draw, in fig. 1, a horizontal line for instance at 25° it will 
intersect the different areas in such a manner that all the amalgams 
from a to b are liquid and therefore, form only one phase. From 
b to c they consist of the heterogeneous system consisting of the liquid 
phase b and of the solid phase ¢ which consists of mixed crystals. 
From ¢ to d every percentage is a homogeneous mixed crystal. 
If we assume that the limiting representatives of the mixed crystals 
1* 
Volt 
