Metals in the Formation of Alloys. 409 



Fig. 2. — Heat of Combination of Copper-Zinc Alloys. 



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Messrs. Johnson, Matthey, & Co. also made and analysed 

 for me five different alloys of silver and copper, containing 

 respectively 64*7, 44*6, 22*7, 15*3, 10'4 per cent, of copper. 

 A considerable number of preliminary experiments have been 

 made with these with the view of determining their heat of 

 combination. The method of procedure was somewhat similar 

 to that described for the zinc-copper experiments. The 

 solvent was again nitric acid, but of lower density than that 

 used in the zinc-copper experiments. To still further faci 

 litate solution, which was slow, the metals and alloys had 

 first to be reduced to exceedingly fine filings by the laborious 

 process of filing down with a very fine file. The results 

 indicate little or no heat of combination. 



\ 



Phil Mag. S. 5. Vol 49. No. 299. April 1900. 2 F 



