PARIS. Academy of Sciences, October 19.—M. Bouchard in the chair.—Precipitated silica: Henry Le Chatelior. The existence of hydrated forms of silica appears to be gener ally admitted, but this view does not appear to have any experimental basis. Various experiments with gelatinous silica are described, all tending to prove that silica exists always in the anhydrous state. The passage through filters is not due to the solubility of anhydrous silica or the presence of a soluble hydrate, but is due to its extremely fine state of division. In confirmation of this, it was found that silica jelly could be used for polishing, metal sections.—The influence of the heating of urine on urinary toxicity: Ch. Bouchard) M. Balthazard, and. Jean Camus. After heating urine to temperatures of 570 C. or above, the toxic power is diminished by one-third, as measured by experiments ori rabbits. The freez ing point of the urine is not affected by this heating.—The action of Saturn's ring: P. Stroobant.—The spectrum of Morehouse's comet, 1908c: A de la Baume Pluvinel and F. Baldet. A comparison of the spectra of the Daniel and Morehouse comets. The latter gives no trace of a continuous spectrum; the photograph shows seven monochromatic images of the comet, the wave-lengths of which are given.—Some properties of curved surfaces: A. Demoulin.—Directed waves in wireless telegraphy: A. Blondel. Referring to recent papers on this subject by MM. Tosi and Bellini, and by M. Turpain, the author points out that he dealt with this subject in a similar manner in 1903.—The electrolytic soda industry: Andre1 Crochet. A theoretical discussion of the electrolytic cell through which the electrolyte is flowing in a stream with a velocity equal to or greater than the velocity of the OH ions.—A new method of attacking iron alloys, and, in particular, the ferrosilicons: Paul Nicolardot. Chloride of sulphur is the reagent suggested for the solution of ferrosilicons or ferrotitaniums. Details are given of the method proposed, which is specially arranged to avoid loss of silicon.—The phenyl transposition. The migration of the naphthyl group in the iodo-hydrins of the naphthalene series: MM. Tiffeneau and Daudel. The migration of groups caused by the addition of hypoiodous acid and subsequent removal of hydriodic acid has been found to occur in the naphthalene series in a manner quite analogous to that previously described for the benzene series. Descriptions are given of the prepara tion and properties of α-allylaphthalene, its isomer, pro-penylnaphthalene, α-naphthyl-α-propanal, methyl-α-naph-thylacetic acid, α-pseudoallylnaphthalene, α-vinylnaphthal-ene, and α-naphthvlethanal.—A modification of the pre paration of methylamine by means of bromacetamide: Maurice Francois. It has been found advantageous to-modify the original Hoffman method in several details. The yield is increased from 35 per cent, to 72 per cent, of the theoretical, and the methylamine hydrochloride is obtained pure and free from ammonium chloride.—The study of colouring matters in solution: L. Pelet-Jolivet and A. Wild. Colouring matters exist in a state of electrolytic, dissociation; some of them are partly in the colloidal state, as was shown by their behaviour in the ultramicroscope. The properties of colouring matters are Intermediate between ordinary saline solutions and colloidal solutions.—Saprophytic cultures of Cuscuta monogyna: Marin Molliard.—The Secamone of the north west of Africa: Henri Jumelle and H. Perrier de la Dathie.—Pigmentary assimilation in Actinia: Georges Dohn.—The hereditary chromatic substratum and the nuclear combinations in the crossing of Amphibia: E. Bataillon.—The gradation and improvement of the instinct in the solitary wasps of Africa of the genus Synagris: E. Roubaud.—The affection known under the name of botryomycosis and its parasite: Gustave Bureau and Alphonse Labbé. This disease is not a mycosis, but is due to an amceba; the botryomyces observed in previous cases is only a plastogamic stage of this organism.—The protonephridia of the adult polychætal annelids: A. Malaquin.—The existing genera of the family of the brachypodides: A. Menegaux.—New researches on the radio-activity of springs producing goitre: M. Répin. All the goitre-producing waters of the Alps gave on examination a measurable radio-activity, due probably to radio-thorium.—The accelerative influence of magnesia in the transformation of saccharose: J. Tribot. Sucrase was prepared from yeast and purified by fractional precipita tion with alcohol. It was found that the purer the pro duct from mineral matter the smaller was the activity, as measured by the amount of sugar fermented in a given time. The mineral substance to which the activity would appear to be due is magnesia.—The ferment from the decapod Crustacea: C. Gerber. This ferment is distinguished from other animal ferments by its resistance to heat and by the special action of acids. Its properties approach those of the vegetable ferments.—The numerical determination of the urinary excretion of nitrogen in various forms in a normal man: L. C. Maillard.—The action of the products of the reaction on the saponification of fats by the pancreatic juice: Mlle. L. Kalaboukoff and Emile Terroine.—The tonality of the sound of percussion: Gabriel Arthaud.—The existence of a new deposit of pre-Pyrenean strata in the middle of the north Pyrenees sheets, in the neighbourhood of Arbas: Léon Bertrand.—The seismic disturbance of October 13, 1908: Alfred Angot. A discussion of the seismograph record at the Pare Saint-Maur Observatory.—The erosion of the Fontainebleau grits: E. A. Martol.—The presence of the genera Salvinia, Nymphsea, and Pontederia in the sparnacian clays of the Montois: P. H. Fritel.