Abstract
PARIS. Academy of Sciences, October 8.—M. Camille Jordan in the chair.-E. Branly: The electrical conductivity of mica. A detailed account of experiments proving the conductivity of mica in thin sheets (0-003 mm.) when under the electromotive force of a single thermoelement (0-004 volt). A special method of testing the mica sheets for holes is described.—G. A. Boulenger: Considerations on the Permo-Triassic reptiles of the order of the Cotylosaurians.—W. H. Young; The theory of trigonometrical series.—M. Guilleminot: Dosimetry and X-radiotherapy in the services of the Army.—G. Sizes: The Pythagorean scale from the point of view of musical acoustics.—M. Guillery: The Brinell hardness test of metals. For this test it is necessary that the conditions, size of ball, total pressure, and duration of the pressure should be rigorously defined. The last condition, not fewer than five minutes, is practically impossible under works conditions where some 10,000 tests a day have to be carried out. The author has worked out a method by means of which the time is reduced from five minutes to two seconds, the imprint being the same as if working under the standard conditions. This is secured by working with an excess pressure above the standard 3000 kg., and a machine is figured and described by means of which the desired pressure is automatically realised; 600 tests per hour can be made with one machine, and data are given proving the accuracy of the results to be within one per cent, of the Brinell standard.—L. F. Navarro: The Flyde peak and Canadas cirque of Teneriffe.—R. Anthony. The primitive embryonic circulation of the Teleostean fishes; study of the embryo of Gasterosteus gymnurus.-E. Bordage: The transformation phenomena of larval tissues in reserve tissues observed during the metamorphoses of insects.-MM. Baudisson and A. Marie; The spondylo-therapy of asthenic and post-traumatic vasomotor or commotional troubles.
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Societies and Academies . Nature 100, 159–160 (1917). https://doi.org/10.1038/100159a0
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DOI: https://doi.org/10.1038/100159a0