384 



Dr. C. R. Alder Wright. 



[Jan. 28, 



Lead 

 Zinc 

 Tin 



22-5 

 42-5 

 35-0 



100-0 



On account of the peculiar serpentine form of the curve obtained by 

 the 1st Method, the positions of the limiting point cannot be so 

 readily deduced by this method as in the case of chloroform, acetic 

 acid, and water. 



The points marked a, &, c, <Z, e, /, g, respectively indicate various 

 " real " alloys obtaine'd in the course of the experiments described in 

 Parts I and II. 



Critical Gurve at 800. 



The experiments at temperatures lying between 750 and 850, 

 detailed in Part II, were similarly supplemented by some additional 

 ones made with mixtures containing lead and zinc in the proportion 

 1:1-75 to 1 : 2, so as to obtain more accurate valuations, more 

 especially in the case of the pairs of conjugate points lying nearer to 

 the limiting point. The following table represents the average 

 values finally obtained from these additional valuations conjointly 

 with the former ones. 



Fig. 5 represents these values, the exterior curve indicating the 

 numbers above stated for temperatures near to 650. The points 

 marked A and B represent two mixtures examined, not separating 

 into two at 800, although lying inside the critical curve for 650. 



On applying Stokes' 2nd Method, the curves marked No. 1, fig. C, 

 are obtained, those marked No. 2 being the corresponding curves 

 deduced from the mean values at 650 above described. Obviously 



