The American Journal of Science and Arts

S. Converse, 1861

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Página 8 - ... that the ratio of the sines of the angles of incidence and refraction is constant for refraction in the same medium, was effected by Snell and Descartes.
Página 406 - ... like those of the Appalachian range. In truth, Mr. Hall observes, the carboniferous limestone is one of the most extensive marine formations of the continent, and is characterized over a much greater area by its marine fauna than by its terrestrial vegetation. " The accumulations of the coal period were the last that gave form and contour to the eastern side of our continent, from the Gulf of St. Lawrence to the Gulf of Mexico ; and as we have shown that the great sedimentary deposits of successive...
Página 231 - The nuclens or central portion is composed of red feldspathic granite, with a series of metamorphic slates and schists superimposed, and thence upon each side of the axis of elevation the various fossiliferous formations of this region follow in their order to the summits of the Cretaceous, the whole inclining against the granitoid rocks at a greater or less angle. There seems to be no unconformability in these fossiliferous rocks from the Potsdam inclusive to the top of the Cretaceous.
Página 356 - Crystalline Form not necessarily an indication of definite chemical composition ; or on the possible Variation of the Constitution of mineral Species independent of the Phenomena of Isomorphism. {LE and D. Phil. Mag., [4], xxi, 406, and this Journal, xxx, 194.) E. So'CHTiNG : Die Einschliisse von Mineralien in krystallisirten Mineralien, nebst' Betrachtungen iiber die Entstehung von Mineralien und Gebirgsarten.
Página 402 - is no other than the Taconic system of Emmons;' which is thus, by these authors, as well as Mr. James Hall, shown to be the natural base of...
Página 396 - ... extensive beds of iron ore, hundreds of feet thick, which abound in that ancient system, correspond not only to great volumes of strata deprived of that metal, but, as we may suppose, to organic matters, which but for the then great diffusion of...
Página 304 - Annual Report of the Regents of the University of the State of New York, on the Condition of the State Cabinet of Natural History, and the Historical and Antiquarian Collection annexed thereto.
Página 167 - Another feature not less conspicuous characterizes the region of corrugations properly so-called. This is a large central valley which passes through the entire system from north to south, forming, as it were, a negative axis through its entire length. This is what Mr. Rogers calls the Great Appalachian valley. At the north it is occupied by lake Champlain and the Hudson river; in Pennsylvania it bears the name of Kittatinny or Cumberland valley. In Virginia it is the Great valley; more to the south...
Página 289 - It is stated by founders that the alloy of 60 per cent of copper and 40 per cent of zinc will present almost precisely the same homogeneity of fracture, whether the test ingot prepared from it be cooled slowly, by exposure to the air, or rapidly, by plunging it into cold water, while alloys containing...
Página 415 - The cycle of operations then begins again, for the parts re-congealed, after having been melted, must, in their turn, through the yielding of other parts, receive pressures from the applied forces, thereby to be again liquefied, and to proceed through successive operations as before.

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