Abstract
PARIS
Academy of Sciences, September 18.—Vice-Admiral Paris in the chair.—The following papers were read:—Examination of observations presented at various epochs regarding the transit of an intra-mercurial planet over the disc of the sun, by M. Leverrier. He cites eleven of these, comprised between 1761 and 1820 (the paper to be continued).—Theorems relating to systems of three segments having a constant product, by M. Chasles.—Note on the period of the exponential ez, by M. Yvon Villarceau.—Lighting by means of products extracted from resinous trees, by M. Guillemare. Distillation of oil of turpentine resting on an equal volume of slightly alkaline water, removal of it by steam, and direct and prolonged action of concentrated solutions of alkaline carbonates on oils of resin, produces complete separation of the colophony and naphthaline these liquids contain; this effect is proved if ammonia no longer affects their limpidity. To utilise the large percentage of carbon for light, two lamelliform currents are arranged round the wick; the exterior, by means of a cone 8 centimetres in height, the other, interior, with a movable conical nipple. The draught is effected with a glass chimney, which has to be ground at the base, so intense is the light. This light is recommended for ships' lanterns and photo-telegraphic apparatus.—On a mode of treatment of phylloxerised vines with lime, by M. Pignede.—M. Lucan presented an instrument employed by the negroes in Congo for capturing serpents. This is a tube, the walls of which are made of pieces of reed interlaced; when the serpent enters they contract through the very efforts which he makes to escape.—On the capture of rattlesnakes, and the supposed association of these serpents with a small owl and a small dormouse, by M. Trécul. Travelling, in 1848, in the region west of Arkansas, he caught snakes by passing over them, when erect, a loop with running knot attached to his ramrod; they remained quite straight and were easily killed. The “villages of little dogs,” or dormice, are sometimes pretty large, e.g., half a kilometre in diameter. One was in a fertile district covered with high herbs, but the ground of the village was entirely denuded by the animals, and little earthworks thrown up, with holes in them, and communicating together. The dormouse takes a survey from the top of these eminences, with only his head thrust out. In coming out, which they do most cautiously, they give a small sharp bark. In another village the author saw a little owl issue from one of the burrows, which was also evidently frequented by dormice; and in another burrow was a "rattlesnake, but this burrow had evidently been long deserted by the other animals.—Symbolic formula giving the degree of the position of points, the distances of which from given algebraic curves verify a given relation, by M. Fouret.—On the physical properties of gallium, by M. Lecoq de Boisbaudran. This subject is noted elsewhere in connection with the Journal de Physique. We here note that the density the author formerly obtained (4.7 at 15°) was different from that to which M. Mendeleef's theoretical views pointed (5.9), for a body between indium and aluminium to which gallium otherwise closely corresponded. Having lately, however, treated some gallium by keeping it half an hour at 60°-70° in nitric acid diluted with its volume of water, washed, heated strongly, then solidified it in dry air, he obtained the number 5.956, which agrees with that of M. Mendeleef.—Anatomical and morphological researches on the nervous system of hymenopterous insects, by M. Brandt. He studies the metamorphoses which occur in the ganglionic chain in passage from the larval to the adult state.—Experiments and observations on vitreous rocks, by M. Meunier. He concludes (1) That vitreous rocks do not represent the product of a vitrification of crystalline rocks, but the latter are derived from the former by way of devitrification. (2) The direct devitrification of obsidian, gallinace, retinite, &c., cannot be produced, and the presence of gases and vapours in the vitreous rocks seems to be the opposing obstacle. (3) This devitrification becomes possible when the rocks, by fusion, are freed from their volatile elements.
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Societies and Academies . Nature 14, 520 (1876). https://doi.org/10.1038/014520a0
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DOI: https://doi.org/10.1038/014520a0