16 Dr. Alder Wright and Mr. C. Thompson. [Feb. 12, 



Fio. 5. 



Further, those alloys where the silver and zinc present were approxi- 

 mately in the proportions denoted by Ag 4 Zn- showed the same 

 marked reddish hne on exposure to the air for a short time, after 

 filing bright, as was observed with the analogous lead-zinc-silver 

 alloys ; thus the two alloys containing the following percentages 

 showed it strongly 



Silver. 

 47-94 

 51-34 



Bismuth. 

 10-05 

 14-34 



Zinc. 



42-01 

 34-32 



Ratio of zinc to silver. 

 1-14 

 1-49 



Mean 1'315 



Calculated for Ag 4 Zn 5 1*33 



as also did some others, the compositions of which lay betwt 

 these limits, which correspond respectively with 84 per cent, of Ag 4 Zn t 

 with a little excess of zinc and some bismuth, and with 80 per cent, 

 of Ag 4 Zn 6 with excess of silver and some bismuth. On the other 

 hand, alloys containing somewhat larger excesses of silver or zinc 

 showed only a much paler tint, whilst little or no coloration was 

 visible with alloys where the percentage of Ag 4 Zn 5 fell below about 

 65 per cent. We prepared some binary alloys of silver and zinc 

 consisting mainly of Ag 4 Zn 6 , with but small excess of either silver 

 or zinc ; these showed the coloration strongly. 



