Scientific Serials

Abstract

THE Amtrican Journal of Science, July.—On the genesis of metalliferous veins, by Joseph Le Conte. From his study of the phenomena of metalliferous deposit by solfataric action at Sulphur Bank and Steamboat Spring, the author argues against Dr. F. Sandberger (“Untersuchungen über Erzgänge,” Wiesbaden, 1882) that all lodes have been formed by deposit from solutions. In this important paper the conditions under which the deposits take place and the character of the solvents are fully discussed. Besides simple water, whose solubility is greatly increased by super-heat and pressure, the most active agency appears to be alkali in the form of alkaline carbonates or alkaline sulphides, or both. Such alkaline carbonate waters, ascending slowly towards the surface through underground fissures, gradually lose much of their solvent power both by cooling and by relief of pressure, and must of necessity deposit in their courses, and form metalliferous veins. In this way even cinnabar and gold may be precipitated. Other powerful agencies may be organic matter of universal occurrence in subterranean waters, and known to be potent in reducing metallic oxides and metallic salts. Mainly by these methods it is argued that alkaline waters at various temperatures, but mostly hot, circulating in all directions, but mainly up-coming, and in any kind of owater-way, but mainly in open fissures, form by deposit mineral veins. Amongst the many subjects incidentally treated are: Association with metamorphism, variation in vein contents; variation of richness with depth; origin of alkaline and metallic sulphides; occurrence of gold; irregular, brecciated, contact, and other kinds of lodes.—Evolution of the American trotting horse, by Francis E. Nipher. By an ingenious process of calculation the author arrives at the conclusion that the maximum speed to which the American trotting horse will constantly approximate without ever reaching it is a mile in ninetytwo seconds.—The burning of lignite in situ, by Charles A. White. The ignition of the lignite beds still burning in Montana, and of others long extinct in Colorado, Wyoming, Dakota, and elsewhere, is attributed mainly, if not altogether, to spontaneous combustion, according as the deposits become by erosion successively exposed to atmospheric influence.—On the paremorphic origin of the hornblende of the crystalline rocks of the North-western States, by R. D. Irving. An examination of about 1000 sections representing the crystalline schists, and eruptives and basic eruptives of a region 400 miles by 300, and of three distinct geological systems, showed the occurrence of no hornblende not clearly or very probably secondary to augite.— On the constituents of the meteorites which fell at Bishopsville, South Carolina, in March, 1843, and at Waterville, Maine, in September, 1826, by M. E. Wadsworth.—A simple method of correcting the weight of a body for the buoyancy of the atmosphere when the volume is unknown, by Jo iah Parsons Cook.— Recent investigations concerning the southern boundaries of the glaciated area of Ohio, by G. F. Wright. The limit is determined by an irregular line running from Aurora near New Richmond, in a north-easterly direction through Chillicothe, Newark, Dunville, and Canton, to New Lisbon, near the Penn-sylvanian frontier.—On the variation of the specific heat of water, by G. A. Liebig.