1890.] 



On certain Ternary Alloys. 



37 



corresponding with a percentage of Ag 4 Zn 5 of about 73 in the first 

 case and 65 in the second. 



It is further remarkable that mixtures of bismuth, zinc, and silver, 

 on standing fused for some eight hours, separate into different 

 ternary alloys, the lighter of which yield curves exhibiting exactly 

 the same peculiarities as those above mentioned, viz., rise to maximum 

 near AgZn 5 , fall again to a minimum, and then a slower rise again to 

 Ag 4 Zn 5 , marked by a red colour. These alloys will be discussed in a 

 subsequent paper. 



Thirdly, the curves obtained by plotting the percentages of silver 

 in the heavier alloys as abscissas and those of zinc as ordinates 

 (Nos. 1 and 2, fig. 6) are in each case such as to indicate that, as long 



Fio. 6. 



as the mixture of metals used contains less than about 41 per cent, of 

 silver in the first case and 28 in the second, the heavier alloy 

 that separates invariably contains more zinc than that formed either 

 when no silver at all is present, or when these limiting proportions 

 are reached. At these limiting proportions the percentage of zinc 

 present is slightly lower than that found in binary zinc alloy, as also 

 is the proportion of zinc calculated per unit of lead, thus 



The lowering is so small that it might readily be attributed to 

 experimental errors, were it not that a precisely similar and much 

 more strongly marked result is obtained with alloys of silver, zinc, 

 and bismuth, as will be shown in a future paper. 



After these limiting proportions are passed the amount of zinc 



