PARIS. Academy of Sciences, Otober 8.—M. H. Poincaré in the chair.—The synthesis of amethyst quartz: researches on the natural or artificial colouring of some precious stones under radio-active influences: M. Berthelot. Natural amethyst was decolorised by heating to a temperature of 300° C., and then exposed to the action of radium chloride, the experiment being arranged so that the specimen was not in actual contact with the radium salt, and was not exposed to its emanations. The violet colour slowly returned. Similar results were obtained with violet fluor-spar, and the effects produced are attributed by the author to the reduction and oxidation of manganese compounds. Ordinary fused quartz tubes are also slowly coloured violet by the radium radiations. The bearing of hese experiments on the coloration of minerals in nature discussed.—The work done at the observatory at the summit of Mt. Blanc: M. Janesen. The season of 1906 was an exceptionally favourable one, and the work done included biological researches on rabbits and guinea-pigs by MM. Moog and Guillemard, heliomtric researches by MM. Millochau and Féry, magnetic studies at different altitudes by M. Senoique, and studies of the surfaces of Venus and Jupiter by MM. Hansky and Stefanik. The results of these various researches will be communicated later to the academy.—The red colour of certain leaves and the colour of autumn leaves: Armand Gautier. The red colour developed in leaves which have been wounded, or in the autumn foliage, is not one and the same in all plants, as has been too hastily assumed. Anthocyanine has been regarded by botanists as the cause of the autumnal red in foliage, and as a uniform product derived from chlorophyll; in the case of the vine this is certainly not the case, since the colouring matter contains neither nitrogen nor phosphorus, two essential constituents of chlorophyll.—Th principle of correspondence for an algebraic surface: H. G. Zeuthen.—Succinic pinacone: Louis Henry. This bi-tertiary alcohol is obtained in good yield by the action of methyibromide of magnesium on ethyl levulate. Both hydrochloric acid and acetyl chloride give the dichiorhydrin (CH3)2C.Cl—(CH2)2—CCl(CH3)2, and dilute sulphuric acid, even in the cold, gives the internal nhydride tetramethyl-tetramethylene oxide, the physical and chemical properties of which are given. Dry distillation gives an unsaturated tertiary alcohol.—The nature of the virtual sugar of the blood: R. Lépine and M. Boulud.—The perpetual secretary announced the death of M. Etienne Georges Sire, correspondant of the academy for the section of mechanics.—Contribution to the study of the calorific emission of the sun: Ch. Féry and G. Millochau. A thermocouple of the same type as those used in the commercial Féry pyrometers is placed at the focus of a silvered mirror, a total reflection prism and eye-piece being added so that readings can be made as in a Newtonian reflecting telescope. Observations were carried out in two ways: placing the centre of the sun in coincidence with the cross wires of the telescope at different hours of the day, and observations of the effects produced at different points of the solar disc. Measurements were carried out at four stations at different altitudes, Meudon (150 metres), Chamonix (1030 metres), Grands-Mulets (3050 metres), and the Janssen Observatory at the summit of Mt. Blanc (4810 metres). Details regarding the standardisation of the apparatus and discussion of the results will be given in a later communication.— Observations of the sun made at the Lyons Observatory during the first quarter of 1906: J. Guillaume. Observations were possible during forty-three days in this quarter, the results of which are summed up in three tables showing the number of sun-spots, their distribution in latitude, and the distribution of the faculæ in latitude.—Observation of the total eclipse of the moon on August 4, 1906, and remarks on the subject of a squall at Phu-Lien, Indo-China: G. Le Cadet.—The liquefaction of wheat starch and seeds: A. Boidin.—The detection of adulteration of butter with cocoa-butter and oleo-margarine: Lucien Robin. Details of a method of analysis based on the difference in the solubilities of the fatty acids of butter and cocoa-fat in dilute alcohol.—The complexes of pure albumen: André Mayer.—The direct action of light on the transformation of the sugars absorbed by the young plants of Pinus pinea: W. Lubimenko.—Some new views, morphological and biological, on the stinging Diptera: E. Roubaud.—A hitherto undescribed organ in the thorax of flying ants: Charles Janet. An account, with a diagram, of a mesonotal diaphragm and metanotal diaphragm in ants after the nuptial flight.—The distribution of the Trias in Greece: Fritz Frech and Carl Renz.—The earthquake in Chili of August 16, 1906: A. Obrecht.—The amount of carbonic acid in sea air: R. Legendre. The average result from thirteen localities was 3.35 parts of carbonic acid per 10,000 of air.