Page:Brinkley - Japan - Volume 7.djvu/257

 familiar with the delicate assaying methods in vogue in the West, and could not determine the quality of either gold or silver with the extreme accuracy attained at an American or European mint. They used a touchstone only, a small plate of black siliceous shale, but used it with such skill that their results—according to an eminent authority, Mr. W. Gowland—did not show a maximum difference of more than one per cent from assays made by Occidental methods. Their success with silver was not equally marked, but they were able to obtain it so pure that five hundred and fifty-five specimens of old silver assayed in recent years at the Imperial Ōsaka Mint were found to contain an average of 99.3 per cent of pure metal. It is, perhaps, scarcely necessary to note that for manufacturing purposes pure gold or silver was never used, the former being alloyed with silver and copper and the latter with copper, not with the idea of debasement, but in order to obtain greater hardness and freedom from vesicular cavities when casting. If, however, the Japanese metallurgist possessed and practised highly skilled methods of freeing the precious metals from impurities, he was also remarkably clever in "surfacing" either gold or silver so as to obtain an appearance of absolute purity. The question here is not of patina,—a legitimate and beautiful feature which Japanese craftsmen had exceptionally ingenious devices for imparting to all the metals used in objects of art,—but to a process originally elaborated in connection with debased coins, and sometimes resorted to by art-artisans of low class, though no kinzoku-shi (gold-smith) of repute ever descended to such deception,—a process of dissolving out the impurities from the