Scientific Serials

Abstract

American Journal of Science, July.—The viscosity of steel and its relations to temperature, by Carl Barus. In this paper the author's studies are mainly restricted to a discussion of the relation between torsional viscosity and temperature as observed with steel in different states of hardness. Reference is also made to the effect of stress on the amount of viscous motion in solids, and to a more general method by which the instantaneous deformation and the gradual deformation produced by stress may be co-ordinated. It is shown that imperceptible gradations lead from the purely viscous deformation which follows strains within the elastic limits to the sudden permanent set which follows strains beyond those limits.—Kilauea in 1880, by William T. Brigham. A detailed account is given of the results of the outbreak of May I, 1880, with a description of the changes that had taken place since the author's previous visit in 1865. The trigonometrical survey then made was found to be already antiquated, the whole boundary perceptibly changed, and Kilauea apparently 5 per cent. larger than eighteen years previously.—Recent explorations in the Wappinger Valley lime stone of Dutchess County, New York (continued), by W. B. Dwight. In this paper (No. 6 of the series) the author deals with the discovery of additional fossiliferous Potsdam strata and pre-Potsdam strata of the Olenellus group near Poughkeepsie. This review of the latest palæontological facts makes it evident that the strata in Dutchess County are simply the continuation of the strata characterizing the Taconic and adjoining series lying northward. But while proving a grand unity, they indicate also an interesting and unexpected variety of rock structure.—Image transference, by M. Carey Lea. By image transference are here denoted curious effects produced on sensitive films, and specially interesting in connexion with the subjects of papers which appeared in the May and June numbers of the journal. In supplement to those papers the possibility is here shown of developing on a film of silver haloid a complete image, a print from a negative for example, without either exposing the silver haloid to light, or to the action of hypo-phosphite, or subjecting it to any treatment whatever, between the moment of its formation and that of its development. The film of silver haloid comes into existence with the image already impressed upon it.—The theory of the wind vane, by George E. Curtis. The author's theoretical studies lead to the inference that the oscillations of both spread and straight vanes are smaller as the vanes are longer and larger; that the spread is always more stable than the straight vane; and that this advantage in stability is greater for long than for short vanes, and is independent of the wind velocity.—On the manner of deposit of the glacial drift, by O. P. Hay. The author's studies of this great geological problem lead to the following conclusions: (1) an ice-sheet moving over a nearly level surface would possess far less abrading power than it would have while descending at a higher angle; (2) through subsidence of the glacial mass by the earth's heat and other causes a constantly increasing proportion of inert matter would collect in the lower-layers of the moving ice; (3) this accumulated material would tend to retard and finally arrest the motion of the lower portions of the glacier, and a permanent deposit would then be gradually made; (4) other detritus might accumulate at the foot of the glacier as a terminal moraine, and still other masses on the top of the already formed deposit when the glacier finally melted.