Page:Proceedings of the Royal Society of London Vol 60.djvu/490

Rh at all upon either steam or carbon dioxide. Magnetic oxide of iron is the final product of the action of steam or of carbon dioxide at a high temperature upon metallic iron :—

Now, metallic iron has been detected in basalts and some other rocks by Andrews (‘ Brit. Assoc. Rep.,’ 1852, Sections, p. 34), and by other observers (e.g., G. W. Hawes, ‘ Amer. J. Sci.,’ Ser. 3, vol. 13, p. 33), and I have verified this observation in the case of the gabbro of Locli Coruisk. But it must be remembered th at both the reactions indicated in the equations just given are reversible, and therefore the presence of metallic iron along with the magnetic oxide in such rocks cannot be taken by itself as final proof that the oxide and the associated gases, hydrogen and carbonic oxide, are the products of the action of steam and carbon dioxide upon metallic iron. The presence of marsh gas in these rocks and the production of large quantities of hydrocarbonous gases, as well as liquid petroleum, in many parts of the earth’s surface, tend to support the view, which is apparently gaining ground, that in the interior of the earth’s crust there are large masses, not only of metal but of compounds of metals, such as iron and manganese, with carbon. Assuming the existence of such material, it is easy to conceive how, by the action of water at an elevated temperature, it may give rise to metallic oxides and mixtures of hydrogen with paraffinoid and other hydrocarbons. This view was put forward some years ago by Mendelejeff (“ Principles of Chemistry,” Translation by Kamensky and Greenaway, vol. 1, 364—365), and it has lately received further support from the results of the study of metallic carbides, which we owe especially to Moissan (‘ Roy. Soc. Proc.,’ vol. 60, 1896, pp. 156—160).

1. Introduction.—The paper is a discussion of Professor Milne’s Catalogues of 8331 earthquakes, recorded as having occurred in Japan, during the eight years 1885 to 1892 inclusive. These catalogues, forming vol. 4 of the ‘ Seismological Journal of Japan,