1891.] 



On certain Ternary Alloys. 



159 



and bismuth thus precipitated with ammonium sulphide. Check 

 experiments made by both methods yielded sensibly the same tin 

 percentages. In order to determine the zinc after removal of bismuth 

 and tin, we first precipitated it as sulphide, then dissolved in hydro- 

 chloric acid, and precipitated as carbonate, finally igniting and weigh- 

 ing as oxide ; this method of treatment being adopted to prevent 

 lime, &c., derived from the vessels used being weighed with the zinc, 

 as would have been the case had the precipitation as sulphide been 

 omitted. Any traces of oxide of iron contained in the zinc oxide 

 were subsequently estimated and subtracted. 



The following figures were derived from the examination of twenty- 

 one compound ingots, the percentages being reckoned upon the sum 

 of the weights of tin, bismuth, and zinc found as 100. With some of 

 the lighter alloys, where zinc was the main constituent, only the tin 

 and bismuth were determined, and the zinc taken by difference. 



Series I. Temperature 600700. 



Series II. Temperature 700800. 



