Page:Proceedings of the Royal Society of London Vol 60.djvu/32

24 Silver........................... 8'1 Lead ......................... 16‘4 Zinc ......................... 9’5 Copper.......................... 4-0 Iron ............................ 0'3 Gold (by difference).. 61'7 100-0

The cause*of the differences revealed by assays made from metal cut from various parts of the ingot was clearly due to liquation ; but previous experience failed to afford any guide to the probable distribution of the precious and base metals in the ingot.

C. Another instance, and on a much larger quantity of gold alloy than the two former examples, was afforded by an ingot weighing 39-625 kilograms, which showed such great variation in its gold contents at various points that the ingot was re-melted and cast into two separate ingots, from which portions of metal were removed for assay by drilling.

All these results f are the averages of assays made in triplicate, and a “ dip ” assay from the melted metal showed that it contained 701 parts of gold in 1000.

The analysis of this metal gave— Zinc ......................... 71 Lead ......................... 4-9 Copper............. 4*8 Iron ....................... 14 Silver......................... 9*2 Gold (by difference).. 72"6 100-0

As in the former case, the gold and silver present were isolated in mass, and the actual yield of fine gold and silver so obtained was as follows:—