American Journal of Science, March.—On the absolute wavelength of light, by Louis Bell. The experiments here described were undertaken with a view to check the results obtained by C. S. Pierce for Prof. Rowland's great map of the solar spectrum, and to furnish a value of the absolute wave-length as nearly as possible commensurate in accuracy with the micrometrical observations. For the wave-length of D, at 2O° C. and 720 mm. pressure, Mr. Bell obtains 5896.08, or in vacuo 5897.71, as compared with 5896.22, Rowland's micrometer measure from Pierce's preliminary result, and 5895.89, Thalèn's correction of Ångström, both in air at ordinary temperature and 760 mm. pressure. But neither of these was corrected for errors in the gratings; hence, obviously, the cause of the discrepancy.—On the relative wavelength of the lines of the solar spectrum, by Prof. Henry A. Rowland. This measurement of the relative wave-lengths of the spectrum and its reduction to absolute wave-lengths by some modern determination has been undertaken in connexion with the photographic map of the solar spectrum on which the author has been engaged for several years, and which is now finished from the extreme ultra-violet wave-length 3200 down to wavelength 5790. Appended are tables of coincidences and of wave-lengths of standard lines.—The norites of the “Cortlandt series” on the Hudson River, near Peakskill, New York (continued), by G. H. Williams. Here are studied the mica norites, the augite norite (hyperite), pyroxenite, and the iron ore and emery in the Cortlandt norite. Owing to incipient alteration, easily visible under the microscope, the West-Chester County emery appears to be of less commercial value than that of Asia Minor.—Natural solutions of cinnabar, gold, and associated sulphides, by George F. Becker. In the course of investigations on the geology of the quicksilver deposits of the Pacific slope, the author has made some studies, here detailed, on the question of the state of combination in which quicksilver is dissolved in natural waters. The solubility of zincblende, pyrite (marcasite), copper sulphides, gold, and other associates of cinnabar, is incidentally examined, the quantitative analysis involved in the process being made by Dr. W. H. Melville.—Fluviatile swamps of New England, by N. S. Shaler. In examining the freshwater swamps of this region, the author has carefully studied the geographical distribution of those formed along the banks of rivers. Although the inquiry is mainly limited to the post-glacial changes in the valleys trending northwards, much light is incidentally thrown on the pre-glacial altitude of the continent. It is made evident that these valleys could not have been excavated by streams of their present slope; hence the inference that the descent of the northward flowing rivers must have been more rapid in pre-glacial times than at present; in other words, this part of the continent was at that time relatively less elevated in its northern parts than it is at present.—On the Mazapil meteoric-iron which fell on November 27, 1885, by William Earl Hidden.—On observations of the eclipse of August 18, 1887, in connexion with the electric telegraph, by Prof. David P. Todd. Referring to his remarks in the Proceedings of the American Academy of Arts and Sciences for 1881, p. 359, the author points out how the proposed method of telegraphic transmission of important observations might be adopted during the eclipse of August 18 next.—On two new meteorites from Carroll County, Kentucky, and Catorze, Mexico, by George F. Kunz. The Kentucky iron has some ethnological interest in connexion with the ornaments of meteoric iron occurring in the mounds of the Little Miami Valley, Ohio, all apparently belonging to one and the same meteoric fall. The Catorze mass, weighing 92 pounds, was found near Catorze, San Luis, Potosi, in 1885. It is one of the caillite group of Stanislas Meunier, and shows the Widmanstätten lines very finely. Analysis: Fe 90.09; Ni and Co 9.07; P 0.24; with specific gravity 7.509.
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