On Certain Properties oj the Alloys of the Gold-Copper Series. 107 



FIG. l. 

 i,io8\ 



1,000 



8. 



900 



800 



Copper 



IO 20 JO 4O 5O 60 70 80 90 100 

 Percentage of Copper in Atoms. 



Freezing points of Alloys of Gold and Copper. 



The initial freezing points of the gold-copper alloys are easy to deter- 

 mine, but the subsidiary or eutectic points are very difficult to detect 

 even if a sensitive autographic recorder is employed. We have great 

 confidence in our conclusion that the alloy containing about 82 per 

 cent, of gold and 18 of copper, and not the one which contains 55 per 



