(1) Three specimens of ancient Chinese spear-heads which are said unearthed from. Yin site ((Remark: Graphics omitted.)) were analysed, and it was found that they consist mainly of copper added with certain quantities of lead and contain no significant amount of tin. (2) From the chemical studies, all these spear-heads are by no means of bronze and they are regarded as the first pure copper implements ever discovered in China. (3) The prevailing opinion which negates the existence of the pure copper age in ancient China must thus be abandoned, and the existence of the copper age in China must be admitted. (4) It is supposed that if these specimens were actually manufactured in Yin dynasty ((Remark: Graphics omitted.)), the pure copper age in China existed at about Yin dynasty ((Remark: Graphics omitted.)), and the beginning of the bronze age followed that age.
1. In 1926 M. A. Apard reported the formation of tetranitrocentralite by the reaction of nitric peroxide upon centralite at ordinary temperature. Owing to want of his experimental data, because of the very small quantity of his sample, it seemed however so doubtful that the author was tempted to set out this investigation, and determined its chemical structure by the spectrochemical and microanalytical methods. 2. Absorption spectra have been studied on the following ten substances. 4-4′-Dinitrodiphenyldiethylurea, 2–4–2′–4′-tetranitrodiphenyldiethylurea, p-nitrophenylurethane, 2–4-dinitrophenylurethane, o-nitroacetanilide, m-nitroacetanilide, p-nitroacetanilide, p-nitroethylacetanilide, 2–4–6-trinitroacetanilide and 4–4′-dinitroethyldiphenylurea. 3. As to the chemical constitution of the reaction product of higher melting point obtained from centralite, it has been proved to be dinitro-diphenylethylurea, which crystallizes from acetone solution in a form of very thin plates of yellowish colour, melting at 213.2-213.5°C., and hardly soluble in ordinary solvents.