Scientific Serials

Abstract

American Journal of Science and Arts, April 1876.—Prof. Wright, of Yale College, examined last year the gases obtained at moderate temperature from a stony meteorite of Iowa County; their chief constituent was carbon dioxide. He has further examined several other meteorites of both classes (stony and iron, five of each), and the results, here communicated, confirm his former conclusions. Not only do the stony meteorites give off much more gas at low temperatures than the iron, but the composition is quite distinct In no case of the latter was the amount of carbon dioxide more than 20 per cent, at 500°, nor than 15 per cent, from the whole quantity evolved, and the volume of carbonic oxide was, in every case but one, considerably larger. In the chondrites, on the other hand, the percentage of carbonic oxide is very small, while the carbon dioxide is (with one slight exception) more than half of the total quantity of gas obtained up to red heat. At a temperature of about 350° it constitutes from 80 to 90 per cent, of the gaseous products, in all cases, while at the heat of 100° it forms somewhat more than 95 per cent, in the two cases examined in this respect. The hydrogen, on the other hand, progressively increases in quantity with rise in the temperature of evolution, and in the last portions given off at a red heat is generally the most important constituent. The evolution of those large volumes of carbon dioxide may be taken as characteristic of the stony meteorites, and its relation to the theory of comets and their trains is certainly of great significance.—Prof. Norton gives a succinct account of researches made with a view to determine the laws of the set of materials resulting from a transverse strain under various circumstances. He studied (i) sets from momentary strains, (2) sets from prolonged strains, and (3) duration of set, and variation of set with interval of time elapsed after the withdrawal of the stress. Some of the results are rather at variance, apparently, with the conception of the ultimate molecule, as made up of a limited number of precisely similar atoms endued with unvarying forces of attraction at certain distances and repulsion at other distances.—According to Prof. Le Conte, mountain ranges are formed wholly by a yielding of the crust along certain lines of horizontal pressure; not, however, by bending of the crust into a convex arch filled and sustained by a liquid beneath, but by a crushing or mashing together horizontally of the whole crust with the formation of close folds and a thickening or swelling upward of the squeezed mass. In an interesting paper he adduces evidence of this from the coast range of California, which is destitute of granite axes, and has been little changed by metamorphism or overlaid by igneous ejections.—Prof. New-comb criticises somewhat unfavourably the physical theories of climate maintained in Croll's recent work on Climate and Time in their Geological Relations.—Prof. Mallet studies the constitutional formulæ of urea, uric acid, and their derivatives, and in an appendix Prof. Marsh describes the principal characters of the Brontotheridæ, with aid of some excellent plates.