1904] Properties of the Alloys oj Silver and Cadmium. 223 



allowed to cool at a moderate rate, the greater part of the mass 

 solidifies at a definite temperature, leaving a very small part only to 

 solidify at a lower temperature. The final freezing point is marked 

 by a minute but distinct check in the rate of cooling. It becomes less 

 marked as the percentage of silver falls below 95 per cent., and 

 disappears altogether before the 80-per-cent. alloy is reached. The 

 80-per-cent. alloy itself solidifies nearly as a whole, and its cooling 

 curve resembles that of a compound, or a pure metal. There is little 



FIG. 2. Curves of Equilibrium of Silver and Oadmium. 



900- 



700- 



500- 



300' 



A single 

 solid 



Solution 



"A 70- 



A single 

 solid Solution 



-500 5 



50 4O 5O 



Percentage of Silver In Atoms. 



100 



doubt that ingots 800 fine in silver would be uniform in composition. 

 As the percentage of silver falls from 80 65 per cent., the initial 

 freezing or liquidus point becomes of less importance, and the pasty 

 stage more pronounced and of longer duration. 



The alloys containing about 66 per cent, of silver and approximating 

 in composition to that required by the formula Ag 2 Cd are somewhat 

 less ductile than those members of the series which are richer in silver. 

 They are more readily attacked by nitric acid than the alloys con- 

 taining either more or less silver. This points to a lack of homogeneity, 

 a conclusion that is supported by the shape of the cooling curve 



