32 



Mr. E. Matthey. 



From this it will be evident, from the horizontal position (6) (of 

 the curve No. I) that the mass solidifies as a whole at 635 C. ; bat 

 there is a second break c in the curve at a temperature of 407 C. ; 

 and there is yet a third break at d, 247 C. These latter points 

 evidently are connected with the solidifying points of lead and zinc, 

 but it is probable that these metals are, in solidifying, associated with 

 some gold. 



The second curve, No. II, represents the cooling of the same mass 

 of gold with 10 per cent, of silver added. It will be seen that the 

 metal has still one main solidifying point 6, at 645 C. The lower 

 point (c) of the former curve is entirely absent, but there is an 

 indication of the lead point at 206. The results clearly indicate 

 that silver is a solvent common to both zinc and lead, which are not, 

 as in the previous case (Curve I) free to separate from each other. 

 Such a mass should be fairly uniform in composition, and assays from 

 different portions of it proved it to be so. 



CURVE No. II. 



Time. 



Cooling of alloy of Au,Cu,Zn,Pb, ( & 'S$ g A /') C.J.*/4C. 



The latter curve (II) seems to change its direction at 767, which 

 is above the main solidifying point of the mass, and it remains to be 

 seen whether this is of any significance. 



The inspection of the curves so obtained at once led me to infer 

 that silver mast be a solvent for zinc and lead when these are present 



