SPECIAL SUBJECTS
the uses to which pewter was put. Japanese pewter resembled that of England, being composed of eighty parts of tin to twenty of lead, without any antimony, zinc, nickel, arsenic, or cobalt. In China this alloy seems to have been employed from time immemorial, and although the first authentic reference to pewter in Japan does not take the student back farther than the second half of the eighth century A.D., the fact then recorded is not the introduction of the metal, but the substitution of Japanese tin for Chinese in its composition. The earliest purposes to which it was applied were to inlay lacquer in combination with mother-of-pearl and to make rims for lacquer boxes. By and by it began to be employed for making vessels—especially those used at marriage ceremonies—and it was then sometimes inlaid with gold, silver, brass, or even bronze. Many pewter tea-canisters are found, as well as vase-shaped wine bottles for placing before Shintō shrines. These tea-jars were frequently of very beautiful form and had cleverly executed decorative designs incised or pierced. The most interesting feature, however, of Japanese pewter is its patina. It has been shown that "when an alloy is in the act of cooling, several definite alloys, in which the molecules of the metal are differently grouped from those of the mass, fall out at definite temperature, so that the solidified metal does not consist really of one alloy, but is a mixture of several, more or less regularly diffused throughout its mass." This property is especially marked in the case of pewter. The Japanese had no thermo-electric pyrometer to enable them to discover it, but they detected it by observation sufficiently to take practical advantage of it. Thus their pewter jars have a very fine
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