Dr. C. B. Alder Wright. 



[June 2, 



16 



formed in each case. With the mixtures yielding the upper tie-lines, 

 the proportions were altered successively to 1-5 to 1, and, finally, to 

 1 to 1 as the difference in density between the two alloys formed 

 diminished ; so as still to give rise to the formation of the two alloys 

 in approximately equal quantities by volume. It was found that 

 when lead and aluminium (without tin) were fused together, well 

 intermixed, and then allowed to stand molten at about 800 for some 

 hours the lead retained, on an average, 0'07 per cent, of aluminium 

 dissolved, and the aluminium T91 per cent, of lead (mean of nine 

 experiments altogether). 



The figures in the last column show that aluminium- tin-lead alloys 

 resemble zinc-tin-alloys in that they furnish a critical curve, the 

 lower ties of which slope to the left (lead side), and the upper ones 

 to the right (zinc or aluminium side). Moreover, the point where 

 the slope of the lower ties is greatest (i.e., practically that where the 

 excess of tin percentage in lighter alloy over that in heavier alloy is 

 a -f maximum) is in each case close to that where the ratio of tin 

 and lead contained in the heavier alloy is that represented by the 

 formula SnPb 3 . 



Al,Pb,Sn alloys Zn,Pb,Sn alloys. 



(5th tie-line). Found. Part V. 



15-97 = 16-04 15-41 



83-61 = 83-96 84-59 



Calculated 

 for SnPb s . 



Tin 15-97 



Lead . 84-03 



100-00 



99-58 



100-00 



100-00 



