1893.] On certain Ternary Alloys. 531 



tendency towards the formation of this difficultly fusible compound 

 with alloys richer in antimony is to cause a partial separation of 

 antimony and aluminium thus combined together in the form of solid 

 particles when the melted alloy is allowed to stand for some time at 

 temperatures not exceeding some 900 ; which separation interferes 

 with the accurate tracing out of the upper portions of the critical 

 curve. 



The discussion in detail of the results obtained with ternary alloys, 

 containing simultaneously aluminium and cadmium (or antimony) is 

 postponed to a future communication; but it may be here noticed 

 that ternary alloys, such as aluminium, cadmium, and lead, or 

 aluminium, cadmium, and bismuth, belong to a class different from 

 that of the ternary alloys hitherto examined. Calling the three con- 

 stituents A, B, and C respectively, three pairs of metals may be 

 formed, viz., AB, AC, and BC. In the alloys previously described, 

 one only of these pairs consists of two metals not miscible together in 

 all proportions, e.g., in the case of lead, zinc, and tin, the pair lead 

 and zinc are immiscible ; whilst the pairs lead and tin, zinc and tin 

 are perfectly miscible. With alloys of the aluminium-cadmium-lead 

 class, on the other hand, two pairs of immiscible metals exist, e.g., 

 aluminium and cadmium, and aluminium and lead. The effect of 

 this difference is to modify very largely the nature of the critical 

 carve deducible by means of the triangular method of graphical 

 representation. 



A priori, there seems no reason why a ternary alloy could not exist 

 of a third class, where all three pairs of metal are immiscible ; hitherto, 

 however, the author has not met with such a case in actual practice. 

 If mixed in approximately equal quantities of the three constituents, 

 such an alloy should divide itself into three different ternary alloys, 

 forming three different layers, viz., one consisting of A, with a small 

 admixture of B and C ; another chiefly containing B, with a little 

 A and C ; and a third principally consisting of C, together with a 

 little A and B. Although metallic mixtures of this class have not 

 been obtained so far, other sets of three liquids have been found 

 possessing this peculiar physical character ; thus a mixture of w itar, 

 castor oil (genuine not largely adultei-ated with other kinds of fixed 

 oil), and. petroleum hydrocarbons (such as ordinary kerosine) separates 

 into three layers when well shaken up and then allowed to stand. 



Alloys containing Zinc with Lead (or Bismuth) and Cadmium as 



Solvent. 



The experiments were carried out with the lead bath arrangement 

 in precisely the same way as before, the weighed metals being fused 

 together with a little cyanide of potassium, and well intermixed , 



VOL. LII. 2 N 



