American Journal of Science, June. —The study of the earth's figure by means of the pendulum, by E. D. Preston. The author first deals with the history of the subject, then states the quantities involved, and supports the method of study in which the figure of the earth is considered separately from its size as determined by measurement of arcs of meridian. The general results of pendulum work are discussed, and the effect of continental attraction and variations in latitude referred to. The best methods of determining the duration of a pendulum oscillation at a given temperature and pressure are also considered.—On the post-glacial history of the Hudson River valley, by Frederick J. H. Merrill. The result of the action of waves upon a shore depends upon the state of rest or movement of the shore. If the land is subject to alternate periods of rest and elevation, a series of terraces will be formed; if the land is slowly rising or subsiding with respect to sea-level, an inclined plane of erosion may be produced. Arguing from this and other facts, the author states provisionally that, after the retreat of the continental glacier from the Hudson River valley, the land stood for a long time at a lower level than at present. A gradual elevation and extensive erosion of the Champlain estuary deposits in the river valley then occurred, and was followed by a depression amounting to about 1oo feet at New York, and which is apparently continuing at the present day.—On alunite and diaspore from the Rosita Hills, Colorado, by Whitman Cross.—Diaspore crystals, by W. H. Melville.—Combustion of gas jets under pressure, by R. W. Wood. Anyone who has watched a burning jet of ether vapour will have noticed that, as the pressure increases, the flame gradually retreats from the orifice and eventually goes out if the pressure is carried beyond a certain point. The author has investigated these phenomena, using various gases. A burning jet of coal gas was extinguished when the pressure was equal to 23 centimetres of mercury-that is, when the velocity of the issuing gas exceeded the speed of combustion for the mixture of gas and air.—Allotropic silver Part iii., blue silver, soluble and insoluble forms, by M. Carey Lea. From the results given in this and preceding papers, the author is led to believe that allotropic and even soluble silver may be formed in numerous ways. The reducing agents may be either a ferrous or a stannous salt, or any one of a variety of organic substances of very different constitutions. From the solubility and activity of this substance, and the parallelism which many of its reactions show to those of silver in combination, it appears probable that silver in solution, like silver in combination, exists in the atomic form.—Note on the submarine channel of the Hudson River, and other evidences of post-glacial subsidence of the middle Atlantic coast region, by A. Linden. kohl-Are there glacial records in the Newark system?, by Israel C. Russell. Facts are adduced in support of the negative view.—A reply to Prof. Nipher on the theory of the solar corona, by F. H. Bigelow.—On the recent eruption of Kilauea, by W. T. Brigham. This is a report of the changes that took place in the crater of Kilauea during March of this year. —Turquoise in south-western New Mexico, by Charles H.Snow.