Abstract
PARIS Academy of Sciences, October 2.—M. Blanchard in the chair.—Reference was made by M. Dumas to the death of Friedrich Wöhler (who was a Foreign Associate).—M. de Candolle presented a work on the origin of cultivated plants. It treats of 247 species; and of all, except three (viz. two species of Cucurbita and the kidney bean), it is possible to say whether they are from the old or the new world. Of 49 species cultivated for more than 4000 years, six or seven are extinct or in course of extinction.—Transit of Venus over the sun, by M. Dumas. The last of the eight missions, that to Florida, under Col. Perrier, left Havre on September 30. M. Dumas gives the complete list. The navy figures prominently. There are three members of the Academy, MM. d'Abbadie and Tisserand, and Col. Perrier; also a nephew of Arago. The eight destinations are: Port-au-Prince, Mexico, Martinique, Florida, Santa-Cruz, Chili, Chubut, and Rio-Negro. Each station will have two equatorials carefully tested. The members have all practised at the Observatory with artificial transits. Most of the missions will use photography. The railway and steamboat companies have given great facilities in transport.—On the shock of imperfectly electric bodies, by M. Resal.—Typographic reproduction of photographs; process of M. Ch. Petit, by M. Marey. Two samples of the process (which is named similigravure, but is not described), are given.—Optical communications between Mauritius and Reunion, by Mr. Adams.—The coercitive force of steel rendered permanent by compression, by M. Clemandot. He attributes the effect to the more absolute homogeneity produced by pressure and cooling under pressure. The steel submitted to compression is soft, and may be filed, bored, &c.—Researches on the action of the intermolecular ether in the propagation of light, by M. De Klercker. He believes he has, by a purely physical method, established a new theory of the action.—On the treatment of phylloxerised vines with coal tar, àpropos of a recent communication of M. Max Ccrnu, by M. Balbiani.—On the employment of heavy oils of coal in treatment against the winter egg of phylloxera, by M. De Laffitte.—A telegram from Munich (October 2) announced that the experimental transmission of force by an ordinary telegraph wire, between Miesbach and Munich (57 km.), by M. Deprez' method, had fully succeeded. Another telegram (September 26) was received from the Emperor of Brazil about the comet. The presence of sodium and carbon was noted.—Observations of the comets Barnard and Common (1882), at the Lyons Observatory, by M. André.—On a class of uniform functions of two independent variables, by M. Piccard.—Hydrodiapasons, by M. Decharme. One of these is formed of a brass tube of elongated U shape, with a nozzle screwed into the curved part and conducting town water. The upper part of each branch is bent round, so that the free ends are closely opposed. To these ends disks or other pieces may be attached with screws. On passige of the water, a regular vibratory motion occurs, with sound; by attraction if the branch-nozzles have thick edges, by repulsion, if they have thin. The experiment is better if the branches are put in water. The feeling when one touches the instrument is like that of shocks from a weak induction coil.—On the nature of vibratory motions which accompany the propagation of flame in combustible gaseous mixtures, by MM. Mallard and Le Chatelier. They have studied, with the help of photography, the period of accelerated and very irregular velocity (accompanied by sound), which follows a (first) period of s-lower, silent, and regular propagation, in a tube closed at one end, and having its combustible gaseous contents (bioxide of nitrogen and sulphide of carbon) lit at the other. A vibratory movement is indicated; the amplitude increasing as the last third of the tube's length is neared (where is one of the ventral segments of vibration). A mean pressure of at least 5 atm. is produced for a few ten-thousandths of a second. The mean velocity of propagation is accelerated as the amplitude and rapidity of the vibrations increase.—Action of anhydrous chloride of aluminium on the acetone, by M. Louise.—On the secretory epithelium of the kidney of batrachians, by M. Bouillot.—Cause of the rot of grapes in America, by M. Prillieux. The rot is due to penetration of Peronospora, not to Phorna uvicola, which is merely developed on the grapes already killed.—M. Daubrée sketched the work of a Committee which has reported to the Minister of Public Works on the means of preventing explosions of firedamp.—M. Daubrée presented a catalogue of the collection of meteorites of the Museum of Natural History on July I, 1882, and noted recent acquisitions, &c.
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Societies and Academies . Nature 26, 592 (1882). https://doi.org/10.1038/026592a0
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DOI: https://doi.org/10.1038/026592a0