color. I n order t o obtain a good color and bright pattern, acid, greasy, or dirty substances must not be rubbed upon the surface. But if an article has been thus damaged it may be restored by cleaning the surface with an abrasive, when the pers~irationof the hand will bring back the black color. 6. If the pattern or color is not very good, it may be improved by abrading the surface and re-forming the black film as described above. Only genuine Wu T'ung will turn black on contact with the perspiration of the band. Imitation artides cannot be turned black in this manner, if they have once been rubbed red.
I was not surprised to find that the fundamental secret had not been divulged: the nature of the "various chemicals" bad not been revealed. But I immediately performed the following experiment. I used an abrasive to remove a portion of the black film from one of my boxes. I then held i t in the palm of my hand, at intervals, on a hot day, and within a few hours a deposit of black had been formed, with only a little of the reddish color of metallic copper showing through. At the same time there was a distinct green color of a copper compound left on my skin. Because of the apparent rBle of moisture, and the fact that i t is only the silver-inlaid surfaces that turn black, is it possible that there is an electrolytic reaction, with an oxide of copper being formed on the surface of that metal? I t may be that the same material is found in Persia, for Janet Miller2says, "We were shown candlesticks and Koran-boxes decorated by n secret process of inlaying with a black metal composition. I t was very effective on the white silver. The skill and patience
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*MILLER, J., "Camel bells of Baghdad." Houghton M a i n Co., Boston and New York City, 1934, p. 208.
that had been expended in the execution of these articles were remarkable. The art of metal inlay is done superlatively well by the Persians and shows a high degree of technical achievement."
Snowso 'THROUGH.THE SURFACE BECAME PERXECTLY BLACK WrrHIN A FEWMONTHS. ON THE SIDESIS A CONVENTIONAL DESIGNOP LATTICE, BATS, Prunus, AND BAMBOO
I am not aware that this black copper has been described before. Its beauty, together with the interesting chemical problem of its production, renders i t worthy of a wider acquai~tance.~
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"his black alloy of copper would appear to be similar to that ("Alchemy, child of Greek philosodescribed by A. J. HOPKINS, phy," Columbia University Press, New York City, 1934) which was used by the Egypt~ansas the basis for their alchemical processes. This alloy of copper, tin, lead, and iron was black on the surface. I s this evidence of a connection between ancient Egypt and China?
A NEW FEATURE In the February issue of the JOURNAL OF CHEMICALtrends in the teaching of high-school chemistry, brief EDUCATION, a short section devoted to the interests of teaching and laboratory technics that have been found high-school chemistry will be inaugilrated. Mr. Elbert valuable, and reports of what various organizations C. Weaver, Instructor in Chemistry, Bulkeley High interested in the teaching of high-scliool chemistry are School, Hartford, Connecticut, and a member of the doing. It is hoped that many high-school teachers will Division of Chemical Education Committee on High- contribute to this section so that i t may function as a School Chemistry, is to assist in editing this section. valuable part of the JOURNAL. Mr. Weaver is spending the year, 1939-1940, as an Articles with a general relationship to introductory exchange instructor a t Polytechnic High School, Long chemistry will continue to appear in the body of the Beach, California. In this section will be found information concerning JOURNAL.
Above all, let nothing distract thee. D o nof strain and struggle, but maintain thy freedom and look things i n the face as befits a man a member of the state, and a morfal creature. And, among the principles which are ever most ready to handfor thee to turn fo, let these twojind a place: first, fhat fhings i n fhemselves have no point of contact with the soul, but are stationed motionless wifhouf, while all unrest proceedr solelyfrom the opinion within; second, that all the oyecfs thou now beholdest will anon change and be no more. Think, and think often, how many changes thine own eyes have wifnessedand know fhat the universe is mufation, and lifc opinion.-MARCUS AURELIUS
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