30 



Mr. E. Matthey. 



TIG-. 8. 



(Fifteen per cent, zinc.) 



It is abundantly evident therefore, that zinc alone will not account 

 for the differences in the ingots of impure gold ; and the question 

 arose, will the presence of a definite amount of silver in any way 

 prevent the irregularity in composition ? 



To test this I alloyed the gold, which contained 15 per cent, of zinc 

 so that it might also contain 7'5 per cent, of silver. 



This was cast into the 3-in. sphere and weighed 3'934 kilograms, 

 and assays made on portions of metal cut from it gave the following 

 results : 



FIG. 9. 



dOi-4 



(Fifteen per cent, zinc.) 



It was intended to contain 



Zinc 15-0 



Silver 7'5 



Gold . 77-5 



100-0 



