Page:Proceedings of the Royal Society of London Vol 60.djvu/38

30 F ig. 8.

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.

It was intended to contain— Zinc................. 15-0 Silver ................. 7‘5 Gold................. 77,5