Page:TASJ-1-3.djvu/32

24

results obtained by Sir Wm. Thomson, not however because the experiments of Sir W. Thomann were imperfectly conducted, but because alloys of inaccurate composition were supplied to him. The reasons, however, why Japanese copper wire, or copper in other forms, was so variable in its physical character were these.

The Japanese were unable to produce uniformly by their refining process, a pure copper in the technical sense of the term. They could produce a copper as free from foreign metals as we could by our methods of refining, and thus far as pure, but they could not produce a copper which should uniformly contain just that proportion of cuprous oxide which was absolutely necessary to give maximum toughness, tenacity, ductility, and electro-conductivity, and without which uniform proportion the purest commercial copper was worthless for most purposes. A deficient quantity of cuprous oxide or an excess would equally condemn an otherwise pure commercial copper. The variations in the physical characters of Japanese refined copper, especially in the form of wire, he had found to be usually due to excess of cuprous oxide and not to the presence of foreign metals, the defects, however, produced by excess of this oxide could not be remedied by any treatment excepting that of remelting under proper conditions.

Japanese crude copper occasionally contained excess of iron, and also of lead, metals however which were removed by refining, and when required for the production of a copper to be used for special purposes as for alloying gold in minting, or for electro-telegraphy, it was advisable to make frequent careful analyses in selecting it.

For further notes on Japanese copper Mr. Gowland would refer those interested to the appendix of the Report of the Imperial Mint, Osaka, for the present year. The copper ores usually worked in Japan yielded from 2⁠1/2⁠ to 12 per cent. of copper, although richer specimens occurred in small quantities. The smelting process of the Japanese was one for which he had great respect, for although it was rude and yielding but a small out-turn compared with European methods, yet he had seen it economically conducted amidst difficulties and in localities where no other process would succeed. Strange as it might appear, the principles upon which it was conducted and the chemical reactions which took place were identical with those of the process followed in Wales at the present time.

The following minerals of iron were worthy of note in addition to those mentioned in the paper:—

Magnetic Iron Sand.—A fine black sand consisting of more or less perfect octahedra of magnetic oxide of iron. It occurred largely in the province of Aki and was smelted there by native methods.

Magnetic pyrites occurred massive in large quantities in several parts of Setsu, in Omi and Yamato, and probably in many parts of Japan. It occurred in the interior of Yamato