Abstract
American Journal of Science, April.—On the use of the stereographic projection for geographical maps and sailing charts, by S. L. Penfield. In continuation of previous papers on the same subject, the various modes of stereographic projection are described with photographic illustrations from models, with remarks on the use of the stereographic protractor for measuring distances along great circles, of measuring spherical angles at a given point, together with various applications in navigation.—On the hind limb of Protostega, by S. W. Williston. A description of a hind limb of what is probably P. gigas, found in the Kansts chalk two years ago. The specimen had for the most part been washed from its matrix, and the original relations of the bones lost. It is characterised by the femur being much more slender than the specimen described by Case.—The physical effects of contact metamorphism, by Joseph Barrel. Although much has been developed in past years concerning the physical, chemical and mineralogical effects of the metamorphism produced in sedimentary beds by the contact of igneous masses, but little has been said concerning the wholesale liberation of gases from the sediments so affected. The shrinkages of volume, the formation of vein fissures, impregnation deposits, and new intrusion of igneous matter and other phenomena due to this cause are considered in the present paper.—An expedition to the Maldives, by A. Agassiz. The most important result of the expedition was the contribution to our knowledge of atoll formation. The present definition of atolls appears to be unjustifiable, as there is every possible gradation between a curved open crescent-shaped bank of greater or less size and an absolutely closed ring of land surrounding a lagoon without direct communication with the sea.—The flower-like distortion of the coronas due to graded cloudy condensation, by C. Barus.—Varying degrees of actinism of the X-rays, by J. O. Heinze, jun. It was found that the rays which are the most active in producing fluorescence are not those which act most vigorously in the photographic plate, and hence that the maximum effect on a platinocyanide screen does not coincide with the greatest photographic effect.
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Scientific Serials . Nature 65, 599–600 (1902). https://doi.org/10.1038/065599b0
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DOI: https://doi.org/10.1038/065599b0