164 



Dr. Alder Wright and Mr. C. Thompson. [Feb. 



the circumstance that it is less soluble in lead (or bismuth), relatively 

 to the zinc present, than either pure zinc or a mixture of zinc and silver 

 in any other proportion. 



Three series of experiments were made exactly corresponding with 

 those previously described with lead-zinc-silver alloys in Part II; in each 

 case the temperature was as near 750 as could be managed, ranging 

 between 700 and 800. The analysis of the alloys was made by dis- 

 solving in nitric acid, diluting, precipitating silver by hydrochloric 

 acid, and washing the precipitate by decantation with hot dilute hydro- 

 chloric acid, in case any bismuth oxychloride might have separated. 

 The filtrate was evaporated to a small bulk and treated with water, and 

 the filtrate from the bismuth oxychloride formed treated with sulphur- 

 etted hydrogen ; the bismuth in the sulphide and oxychloride thus 

 obtained was determined by converting the joint precipitates into 

 oxide by dissolving in nitric acid, precipitating boiling with ammonium 

 carbonate, and igniting. The zinc was determined as in the former 

 alloys, and courected for small quantities of iron derived from the 

 crucibles, &c. 



Series I. Time of fusion, 8 hours. Temperature 700800. 



The above figures were derived from a series of twenty-eight coi 

 pound ingots, each prepared from equal weights of zinc and bismut 

 with varying proportions of silver. They show almost exactly tl 



