The American Journal of Science and Art, July.—The original articles are:—On the United States Weather Map, by E. Loomis, which we have already noticed.—On a magnetic proof plane, by H. A. Rowland. The apparatus required is a small coil of wire 1/4 to 1/2 inch in diameter and containing 10 to 50 and a Thomson galvanometer. Having attached the small coil (or magnetic proof plane, as Mr. Rowland calls it) to the galvanometer, it has to be laid on the required spot and then suddenly pulled away and carried to a distance, and the momentary deflection of the galvanometer will be proportional to that component of the lines of force at that point which is perpendicular to the plane of the coil. By a coil of this kind it is possible to determine the intensity of the magnetic field at any point and thus be able to make a complete map of it. Illustrations of the method are given.—On pseudomorphs of chlorite after Garnet at the Spurr Mountain Iron Mine, Lake Superior, by Raphael Pumpelly, with a coloured plate of a section magnified.22/1.— A brief note on the application of the horizontal pendulum, by Harcourt Amory.—Explosive properties of methyl nitrate, by Carey Lea. This communication describes a new method and the requisite apparatus for preparing it, so that danger is reduced to a minimum.—On zonochlorite and chlorastrolite,. by G. W. Hawes.—On glycogen and glycocoil in the muscular tissue of Pecten irradians. The glycogen has the formula of the sugars of that of the starch group plus a molecule of water. The amount of glycocoil occurring in the tissue is small. Analyses are given.—On Dr. Koch and the Missouri mastodon, by Edmund Andrews. The object of the article is to show that Dr. Koch's testimony contributes nothing reliable on the question of the occurrence of human remains in conjunction with the mastodon.—On the rate of growth of corals, by Prof. Joseph Le Conte. Examining a grove of madrepores he noticed that all the prongs grew to the same level, which at the time were very near the surface; and that all of them were dead at the tips for about three inches. The varying level of the ocean at the place is known from the Coast Survey Report, and as it seems that during the high water the madrepores grow up, the living points of the madrepores grow up till the descending waterlevel exposes and kills them down to a certain level; with the rise of the mean level again new points start upwards. The annual growth, calculated from the known rise and fall of water level, is from 31/2 to 4 inches per annum.—Results of dredging expeditions off the New England Coast in 1874, by A. E. Verrill. Lists of species are given.—Examination of gases from the meteorite of Feb. 12, 1875, by A. W. Wright.—Discovery of two new asteroids, 144 and 145, by C. H. Peters. The diameter of 144 is as the 10th, and 145 as 11.5.—The discovery of a method of obtaining thermographs of the isothermal lines of the solar disc, by Alfred M. Mayer. We reprint the paper this week.