26 



Mr. E. Matthey. 



In order to ascertain the effect exerted by these two metals lead 

 and zinc in conjunction with gold, I prepared an alloy of 700 parts 

 pure gold and 300 parts pure lead, and after mixing and casting into 

 an open mould I cast the melted alloy into a spherical mould 2 in. 

 in diameter, made of cast iron. Determinations made from different 

 parts, after cutting the sphere into two halves, gave the following 

 results, the assays being made in triplicate upon each portion of 

 metal removed. 



(The weight of this sphere was a little over 2 kilograms.) 



FIG. 1. 



The result shows a decided tendency of the gold to liquate to the 

 centre of the mass. 



In the next experiment gold was alloyed with lead and zinc in the 

 following proportions : 



Gold 75 parts. 



Lead 15 



Zinc 10 



adding the zinc when the alloy of the first two metals was thoroughly 

 fluid, and after casting this into an open mould, the alloy was 

 remelted and cast into the 2-in. spherical mould before mentioned. 

 This alloy was extremely hard and very brittle. Portions removed 

 from the different parts of the sphere, after cutting it across, gave 

 the following results : 



FIG. 2. 





