JAPAN
cluded from bronze destined for the manufacture of swords and other weapons in which strength and hardness were essential, but it always found a place in bronze intended for artistic castings. An interesting fact is that the ancient bronzes of Egypt, Rome, and Greece were alloys in which the principal constituents varied similarly, though these Occidental bronzes differed from the Japanese in being entirely free from arsenic and antimony. It must not be assumed, however, that the presence of the latter metals in Japanese bronze of later times was due to defective processes, whatever may have been the case formerly. The cause is to be sought in the addition of a pseudo-spiese (called shirome); an alloy of copper, arsenic, lead, and antimony, obtained as a by-product in separating silver from copper by liquation with lead, a process introduced into Japan by the Portuguese in the sixteenth century, but subsequently altered by the Japanese so that "the results achieved with it far surpassed in economy and in completeness of separation of the respective metals anything that had been accomplished in its original form."[1] Alone shirome is worthless, but the Japanese discovered that by employing it as a constituent of bronze, the latter obtained greater hardness without impairment of fusibility, so that it took a sharper impression of the mould. From the early part of the seventeenth century shirome was constantly added to bronze destined for ornamental or useful castings, since, in addition to the advantages mentioned above, it facilitated the production of a deep gray patina, which was thought specially suitable for silver inlaying. Competent experts have decided that Japanese bronze is eminently
- ↑ See Appendix, note 17.
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