Page:Proceedings of the Royal Society of London Vol 60.djvu/31

Rh Three assays at b—bottom of ingot—

Gold. Silver. 1 .............. 3325 0-181 2 .............. 652-0 0-095 3 .............. 410-5 0-057 And seven assays were made from a “ Gold. dip,” viz.—

Silver. 1 .............. 622-0 — 2 .............. 574-4 0-072 3 . . .......... 653-5 o-oii * 4 .............. 623-2 — • 5 .............. 580-0 0-138 6 ............- 603-3 — 7 .............. Average of the whole number 562-3 of the assays made .... 576-2 0-090

It became evident, therefore, that the only method of determining the true quality of this ingot consisted in actually separating the gold and silver in mass, and this was effected by dissolving in nitroliydrochloric acid, the silver being recovered as chloride and reduced to metallic silver, and the gold precipitated by iron chloride as pure metallic gold.

The result of this operation yielded G old.............. 7"504 kilograms. Silver .......... 0928 „

which showed that the standard fineness of the ingot was Gold .............. 614-0 Silver.............. 75-8

and its true value £1,028 ; while the value, as calculated from the average of the assays previously made, G old................. 576 Silver................. 0'090 would have been only £965.

Analysis proved that the metals present other than gold were as follows :—