24 



Dr. C. B. Alder Wright. 



[June 2, 



by PbAl 7 , whilst zinc-lead-silver alloys gave a ratio near that indicated 



by the formula Pb 2 Zn (Part V). 



Found. 



Calculated. ( A * 



Pb 95-8 40-0 = 95-8 



4-2 1-75 = 4-2 



100-0 



41-75 



100-0 



Mixtures of Aluminium, Bismuth, and Silver. 



A series of mixtures of aluminium, bismuth, and silver was pre- 

 pared in precisely the same way, the temperature during the period 

 of tranquil fusion being the same, viz., between 830 and upwards of 

 900, averaging about 870, or a little higher ; for the lower ties, as 

 before, bismuth and aluminium were employed in about the relative 

 proportion 2 to 1, increasing quantities of bismuth being used for the 

 upper ones, until the proportion reached about 10 to 1. The alloys 

 were analysed by dissolving in nitric acid, and precipitating the silver 

 as chloride, and diluting the nitrate and precipitating with sulph- 

 uretted hydrogen ; the sulphide of bismuth was ultimately weighed 

 as oxide, after dissolving in nitric acid and precipitating with ammo- 

 nium carbonate ; whilst the aluminium was precipitated from the 

 sulphuretted hydrogen nitrate by ammonia, and the weighed alumina 

 corrected for silica and ferric oxide, as before ; the results being in 

 all cases calculated upon the sum of silver, bismuth, and aluminium 

 found as 100. 



The following table represents the results obtained by the exami- 

 nation of 20 compound ingots, representing 40 alloys : 



