Note 27 — BOOK XI. (continued 2)

It seems scarcely necessary to discuss in detail the complicated "flow scheme" of the various minor bye-products. They are all re-introduced into the liquation circuit, and thereby are created other bye-products of the same kind ad infinitum. Further notes are given on:—

Liquation thornsNote28.

Slags"30.

Ash-coloured copper"29.

Concentrates"33.

Cadmia"32.

There are no data given, either by Agricola or the later authors, which allow satisfactory calculation of the relative quantities of these products. A rough estimate from the data given in previous notes would indicate that in one liquation only about 70% of the original copper came out as refined copper, and that about 70% of the original lead would go to the cupellation furnace, i.e., about 30% of the original metal sent to the blast furnace would go into the "thorns," "slags," and "ash-coloured copper." The ultimate losses were very great, as given before (p. 491), they probably amounted to 25% of the silver, 9% copper, and 16% of the lead.