Scientific Serials

Abstract

American Journal of Science, August 1890.—On the cheapest form of light, from studies at the Allegheny Observatory, by S. P. Langley and F. W. Very. The authors have made a long and interesting series of observations, by means of the bolometer and spectroscope, on the light radiated by the firefly (Pyrophorus noctilucus, Linn.) found in Cuba and elsewhere. It has been previously shown that in all industrial methods of producing light, like the candle, lamp, or gas, more than 99 per cent, of the energy is, as far as illumination goes, wasted; and in sources of higher temperature, like the incandescent light and electric arc, even under the most favourable conditions, an enormous waste is involved. The study of the radiation of the fire-fly demonstrates that it is possible to produce light without heat other than in the light itself; that this is actually effected by nature's processes; and that these are “cheaper,” that is, more economical in energy, than any industrial method now known. From the observations and facts given there seems no reason why the light should not one day be produced in the laboratory, and used for industrial purposes.—Contributions to mineralogy, No. 48, by F. A. Genth. Analyses are given of the following minerals: tetradymite, pyrite, quartz (pseudo-morphous after stibnite), gold in chromiferous clay from Los Cerillos, New Mexico, zircon, scapolite, garnet, titaniferous garnet, allanite, and lettsomite from Arizona and Utah.—A curious occurrence of vivianite, by Wm. L. Dudley.—Classification of the glacial sediments of Maine, by George H. Stone.—The direct determination of bromine in mixtures of alkaline bromides and iodides, by F. A. Gooch and J. R. Ensign. The method described is as follows: the neutral solution containing the bromide and iodine is diluted to 600 c.c. or 700 c.c., and about I c.c. or 1˙5 c.c. of strong sulphuric acid, or from 2 c.c. to 3 c.c. of the acid mixed with an equal volume of water, are added; a sufficient amount of sodium or potassium nitrite is then introduced, and the liquid is boiled until the colour has disappeared and the escaping steam no longer gives to red litmus-paper the characteristic colour of iodine. The residual liquid is then treated with excess of silver nitrate, and the precipitated bromide filtered off, dried, and weighed.—Some Lower Silurian graptolites from Northern Maine, by W. W. Dodge.—Siderite-basins of the Hudson River epoch, by James P. Kimball. Some interesting facts bearing on the structural geology of the Taconic area extending to the Hudson River, and on the geology of the whole Taconic region, are brought together and discussed.—On a new variety of zinc sulphide from Cherokee County, Kansas, by James D. Robertson.—Two new meteoric irons, by F. P. Venable. An analysis of a meteorite from Rockingham County, N.C., gave the result: Fe, 87˙01; P, 0˙04; SiO2, 0˙53; Cl, 0˙39; Ni, 11˙69; Co, 0˙79 = 100˙45. Another meteoric iron from Henry County, Vancouver, gave: Fe, 90˙54; Cl, 0˙35; SiO2, 0˙04; P, 0˙13; Co, 0˙94; Ni, 7˙70 = 99˙70.—Notice of some extinct Testudinata, by O. C. Marsh.