Abstract
PARIS. Academy of Sciences; September 15.—M. Leon Guignard in the chair.—E. Goursat: Remarks on a problem of vectorial geometry.—H. Le Chatelier and B. Bogitch: Refractory properties of aluminous materials. In spite of the high melting point of alumina, it has proved in practice to be an unsatis factory refractory material. Measurements of the resistance to crushing at varying temperatures of alumina bricks, made up in different ways, are given, and it is shown that all become plastic at tempera tures between 1200°C. and 1500°C. This. explains their failure in steel furnaces, where the temperature exceeds 1600°C. In special types of laboratory furnace, where the material is not required to bear pressure, alumina can be used with advantage, and details are given of the method of building such a furnace capable of sustaining a temperature of 1600°C.—H. Le Chatelier: The development of scientific research in the United States.—A. Foch: Concerning the period of water-mains with a unique characteristic, furnished with an air-chamber.—L. Picart and F. Courty Observations of the Metcalf and Borrelly comets made at the Bordeaux: Observatory (38-cm. equatorial). Details of observations made on August 23 . (Metcalf), August 31, and September 1 and 4 (Borrelly).—L. Picart and F. Courty: Further observations on these two comets. Measurements are given for September 5, 9, 10, and 11.-H. Vanderlinden: Elements of the comet 1919c (Borrelly).—L. Guillet, T. Durand, and J. Galibourg: Contribution to the study of the tempering of certain aluminium alloys. The alloys studied were of the duralumin type, containing about 3.7 per cent, of copper, 0.6 per cent. of manganese, 0.25 per cent, of zinc, and 0.43 per cent, of magnesium. The breaking strain, elastic limit, and hardness all increase with the time after tempering, a remarkable property shown by this alloy alone. The hardness was measured at varying inter vals of time after tempering at temperatures of 3oo°C, 400°C, 450°C, and 500°C, and the transformation point found to lie between 400° C. and temperature was above 400°C.—A. Carpentier The fructifications of sphenopteris herbacea bhenofteris herbacea.—L. Daniel: The stability and heredity of the Crataegomespilus and the Pirocvdonia.—V. Galippe: The resistance of living intra-cellular agents to the action of certain chemical substances. The microzvmas; of tissues are, not destoyed by glycerol, alcohol, chloroform, or bv lapse of time. Herlant o New researches on the inhibiting action exercised by the snerm of the mollusc on the fecunda tion of the egg of, the sea-urchin.
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Societies and Academies . Nature 104, 128 (1919). https://doi.org/10.1038/104128a0
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DOI: https://doi.org/10.1038/104128a0