28 



Mr. E. Matthey 

 FIG. 4. 



This sphere seems constant all over. 



In order to see what was the effect with pure gold alloyed with 

 metallic zinc only, I cast an alloy of fine gold with 5 per cent, of 

 zinc into a 3-in. spherical mould. The weight of the sphere was 

 3-438 kilograms. 



The results were as follows : 



Fia. 5. 



(Five per cent. zinc. 



A slight but decided tendency of liquation of gold towards the 

 centre. 



The same alloy, containing 95 per cent, of gold and 5 per cent, of 

 zinc, was then alloyed with a further 5 per cent, of zinc and cast 

 into the same sphere. This weighed 4*218 kilograms. The results 

 were as follows : 



