294 



BRIDGMAN. 



borates the theory that Cd may be in a state of unstable internal 

 equilibrium, or at any rate of internal equilibrium which is very slowly 

 readjusted after any change of external conditions. The measure- 

 ments of the previous paper did not suggest any such state of affairs, 

 but this need not be surprising, because it is known that thermo- 



0° 



10° 20° 30° 40° 



50° 60° 



Temperature 



Cadmium 



70° 80° 90° 100° 



Figure 6. Cadmium. Thermal E.M.F. of a couple composed of one 

 branch of uncompressed metal, the other compressed to the pressure in kg./cm.^ 

 indicated on the curves, the junctions being at 0°C and the temperature 

 plotted as abscissae. 



electric quality is much more sensitive to slight changes than resist- 

 ance. At the same time, it does not seem to me that unstable internal 

 equilibrium necessarily points to polymorphism as an explanation. 

 I have already discussed this matter in some detail in another paper.^ 

 With regard to the bearing of these particular measurements on the 



8 P. W. Bridgman, Proc. Amer. Acad. 52, 636, 1917. 



