In a paper on "The Transition from Pure Copper to Bronze made with Tin," he writes as follows: "The use of copper in Egypt can be traced from the Fourth Dynasty, when King Seneferu captured the copper and turquoise mines of the Sinaitic peninsula. Tools made of this metal have been found not only in Egypt, belonging to the Fourth, Sixth and Twelfth Dynasties, but also in Assyria, at Lachish in Palestine, Hissarlick in Asia Minor, and Naqada. Attempts were made to render this copper harder and stronger, and that in three ways. First, the admixture of a large quantity of suboxide of copper or of its formation in the process of smelting, as seen in adzes from Egypt and Palestine, and perhaps Naqada. Second, the presence of a little arsenic or antimony, as shown in many tools from Kahun dating from the Twelfth Dynasty, and from the Sinaitic mines, as shown in a communication to the French Academy by Berthelot a few weeks since. Third, the admixture of a little tin, as at Kahun, the Sinaitic mines, and Cyprus, perhaps not exceeding one per cent. When, however, the superiority of tin, as the hardening material, came to be acknowledged, it was added in larger quantities and formed the alloy known as bronze. Such proportions as 4 and 6 per cent, occur in early specimens, as at Hissarlick, but subsequently about 10 per cent, was usually employed. Tools of this composition are found not only in Egypt during the Eighteenth Dynasty, but in most
