34 Dr. Alder Wright and Mr. C. Thompson. [May 8, 



Series II. Time of Fusion, 24 hours. Temp., 750 850. 



(after correction) as 100. In the case of the lighter alloys, where 

 zinc was the main constituent, as a rule the silver and lead only 

 were determined, and the zinc taken by difference; but with the 

 heavier alloys the zinc was invariably directly determined. 



Series I is derived from the examination of thirty-eight compound 

 ingots, and Series II from seventeen, several of the analyses quoted 

 being the mean compositions derived from two mixtures nearly alike. 

 The average loss by volatilisation and oxidation was about 4 grams 

 out of 50 60 = about 8 per cent., in Series I, and 6 or 7 grams 

 = about 13 per cent., in Series II, the zinc being the metal chiefly 

 affected. 



On plotting these figures as curves, it is noticeable, firstly, that the 

 distribution of silver between the two alloys formed is such as 

 throughout to yield a curve overlying the base line, and exhibiting a 

 rise to a maximum, and subsequent slight fall. Thus curves 1 and 2, 

 fig. 4, represent the numbers in Series I and II respectively, the 

 percentages of silver in the lighter alloys being here taken as 

 abscissae, and the figures in the last column as ordinates. 



Next, the curves obtained by plotting the percentages of silver 

 and lead in the lighter alloys as abscissae and ordinates respectively 

 are most remarkable (curves 1 and 2, fig. 5). At first the two curves 

 do not coincide, but they present the same general feature of rising 

 to a first maximum, and then falling again to a point but little above 

 the starting level, after which the two do not differ from one another 



