1890.] 



On certain Ternary Alloys. 



33 



silver present no lead chloride separated. The turbid liquid was 

 kept hot in the water-bath for an hour or two, until the silver 

 rlilnride had subsided, and was then filtered hot, the silver chloride 

 being boiled up two or three times with water to wash out any 

 lead chloride that might possibly have separated. The filtrate was 

 evaporated with pure sulphuric acid in excess, and the lead sulphate 

 formed separated and determined in the usual way. As with the 

 lead-zinc-tin alloys described in Part I, it was found necessary to 

 precipitate the zinc contained in the filtrate from the lead sulphate 

 as sulphide, and to redissolve this (after filtration) in hydrochloric 

 acid and precipitate whilst boiling as carbonate by sodium carbonate, 

 finally weighing as ZnO ; if the precipitation as sulphide were 

 omitted, sensibly too high values were obtained from the presence of 

 lime, presumably derived from the glass and porcelain vessels used. 

 The ZnO, after weighing, was dissolved in hydrochloric acid and 

 supersaturated with ammonia, and the trifling precipitate of alumina 

 and ferric oxide (derived from the crucibles and clay test-tubes) 

 estimated and subtracted. The figures given below are in all cases 

 calculated upon the sum of the silver, lead, and zinc thus found 



Series I. Time of Fusion, 8 hours. Temp., 750850. 



VOL. XLVIII. 



