Henri Moissan Research Articles

Calcium Metal

ELECTROMETALLURGY has at last succeeded in producing metallic calcium in commercial quantities, and at what must be considered a relatively low price. Until within a few weeks ago this metal had only been available in very small amounts, and remained a rare laboratory specimen; it is now obtainable at a price per kilogram less than that charged by most chemical dealers for a small one-gram sample. Humphry Davy first formed the amalgam by electrolysing lime, mixed with mercuric oxide and slightly moistened, with a mercury kathode; he isolated the metal in small quantities by distilling off the mercury. Since then many chemists have tried in vain to find a method suitable for its preparation on a larger scale. Matthiesen, making use of Bunsen's suggestion of applying high current density at the kathode, only succeeded in obtaining a fewT grams at a time by electrolysis of the fused chloride, or of mixtures of calcium and other chlorides having a lower fusing point. Henri Moissan, as the result of a critical study of the numerous proposed methods, was able to prepare somewhat larger quantities of the metal. His method was essentially a modification of that proposed by Lies-Bodart and Jobin in 1858, which consisted in reducing fused calcium iodide with metallic sodium. Moissan found that molten sodium forms an excellent solvent for calcium, and by heating calcium iodide with a large excess of sodium obtained on cooling a cake of the sodium-calcium alloy resting on the sodium iodide. Small quantities of the alloy were thrown into well cooled absolute alcohol, which reacts with the sodium leaving the calcium pure, but in the state of a fine crystalline powder. This powder can be agglomerated by pressure and fusion, and thus Moissan prepared the fine specimen ingots of this metal which so greatly interested visitors to the Paris Exhibition of 1900. It is largely to him that we are indebted for a knowledge of the properties of the pure metal, of which he prepared some 4. kilos, by this process. Contrary to the earlier descriptions, calcium is a white metal, the yellow coloration being due to a film of nitride; its melting point is about 760° C, and its density 1.85. The definite compounds which it forms directly with hydrogen and nitrogen promise useful applications in the laboratory in cases where it is necessary to remove these gases.

Societies and Academies

PARIS. Academy of Sciences, July 16.—Maurice Lévy in the chair.—On the uranium radiation, by M. Henri Becquerel. By mixing uranium chloride with barium chloride and precipitating with sulphuric acid, a precipitate of barium sulphate is obtained which is more or less radio-active according to the quantity of barium salt introduced. The radio-activity of the uranium salt remaining undergoes a corresponding diminution. It cannot be settled from these experiments whether uranium salts possess a radio-active power of their own, or whether this property is due to an admixture of an impurity.—Preparation and properties of two borides of silicon, by MM. Henri Moissan and Alfred Stock. By heating together, with special precautions, in a tube of infusible material a mixture of silicon and boron in the electric furnace, two new borides of silicon are produced, SiB3 and SiB6, which can be separated by taking advantage of the facts that SiB3 is more readily attacked by fused potash, and SiB6 is more readily destroyed by concentrated nitric acid. Both compounds resist the attack of most reagents and are very hard, scratching ruby with facility.—On the crystallisation of gold, by M. A. Ditte. Gold leaf, heated with a mixture of salt and sodium pyrosulphate or ferrous sulphate, is attacked, and shows traces of crystalline structure, although the temperature has been far below that of the fusion of gold. Platinum gives rise to similar phenomena under the same treatment.—On the solubility of calcium phosphate in the water of soils in presence of carbon dioxide, by M. Th. Schicesing. Neutral Ca3(P04)2, obtained free from sodium salts, is practically insoluble in water free from dissolved carbon dioxide. The solubility increases with the amount of dissolved carbonic acid, but if this is accompanied in solution with the corresponding amount of calcium bicarbonate, the solvent action is practically destroyed.—New researches on double fertilisation in angiosperms, by M. L. Guignard. In addition to the cases previously given of double fertilisation in monocotyledons, this has now been observed in Narcissus poeicus and Scilla bifolia. In dicotyledons, Anemone nemorosa has been most completely studied.—The movements of the air on encountering surfaces of different forms, by M. Marey.—Observations of the planets (F.G.) and (F.H.) made with the large equatorial of the Observatory of Bordeaux, by MM. G. Rayet and F. Féraud.—On the formation of coal basins, by M. Grand' Eury. Remarks on the mode of formation of the Loire basin.—M. Lipschitz was nominated a correspondent in the section of Geometry.—On the instability of certain periodic solutions, by M. Levi-Civita.—On the ternary bilinear forms of Hermite, by M. Louis Kollros.—On the law of corresponding states, by M. Daniel Berthelot. After discussing various modifications that have been suggested for bringing Van der Waals' formula into closer agreement with experiment, the author concludes that the three constants fc, vc, Tc are not sufficient to rigorously define the function f (f, v, T) of a substance. It is necessary to add two new constants, Tm and Vm, corresponding to the displacements of the zeros of volume and temperature —On the temperature of maximum density of aqueous solutions of ammonium chloride and lithium bromide and iodide, by M. L. C. de Coppet. The molecular lowering of the temperature of maximum density varied from 7.16 for ammonium chloride to 8.3I for lithium iodide.—On the electrolytic estimation of bismuth, by M. Dmitry Balachowsky. It is possible to get a coherent metallic deposit of bismuth allowing of washing, provided the following conditions are observed:

Societies and Academies

PARIS. Academy of Sciences, October 3. —M. Van Tieghem in the chair.—The analysis of some commercial specimens of calcium carbide, by M. Henri Moissan. If calcium carbide is prepared from impure materials, it is liable to contain calcium phosphide and aluminium sulphide, both decomposable by water,. giving hydrogen phosphide and sulphide respectively. In the residue left after treatment with water, besides lime, there is found calcium, iron, and carbon silicides, calcium sulphide, and sometimes graphite. Crystals of silica are also present, but a careful search for diamonds gave negative results in all the samples examined.

Crystallised Carbon

IN the course of some researches on the properties and modes of formation of the various forms of carbon, M. Henri Moissan has succeeded in reproducing the variety of diamond known as carbonado, or black diamond, and has even obtained some minute crystals of the colourless gem. An account of his results in the Comptes Rendus of February 6 is followed by an article on the reproduction of the diamond, by M. Friedel, and some congratulatory remarks by M. Berthelot.

Societies and Academies

PARIS. Academy of Sciences, October 20.—M. Duchartre in the chair.—Study of the movement of a double cone which appears to rise, though it really descends, on an inclined plane, by M. H. Resal. A double cone placed on two guides inclined to the horizon, and nearer to one another at the lower than at the upper end, appears to ascend. The author has studied the mechanics of this movement.—Note on lightning-flashes which meet one another, by M. A. Trécul. On September 29, M. Trouvelot presented a paper on the identity in the structure of lightning and discharges from an induction machine. The author calls attention to the fact that he made similar observations ten years ago.—Observations of Brookes's comet (March 19, 1890), made with the great equatorial of Bordeaux Observatory, by MM. G. Rayet, L. Picart, and Courty. Seventy-one observations for position are given, extending from June 21 to October 12.—Remarks relative to a cause of variation of latitudes, by M. R. Radau. The movements of the sea, as well as certain meteorological phenomena (avalanches, &c.), may give rise to small deviations of the axis of our globe. It is shown that a mass of water 2000 cubic kilometres in size could produce an effect large enough to be observed.—On the established variations in the observations of the latitude of the same place, by M. A. Gaillot. Observations made at Berlin, Potsdam, and Prague, indicate that the latitude of a place is subject to a periodic variation, the maximum occurring in the summer, and the minimum in the winter, the amplitude of the oscillation about the mean value being ± 0″˙25. M. Gaillot gives two hypotheses to account for this variation, and points out the means of testing each of them.They are: (1) the axis of rotation is changed in the interior of the earth, the poles describing a circumference about the mean position, of which the radius is 0″˙25 (7 or 8 metres); (2) the accepted periodic variation in observations of latitude is due to refraction phenomena.—Organization of spectroscopic researches with the great telescope of Paris Observatory, by M. Deslandres. (See Our Astronomical Column.)—Two solar prominences observed at the Haynald Observatory, Kalocsa (Hungary), by M. Jules Fényi. On August 15, at 9h. 39m., Paris mean time, a prominence reaching a height of 323″, was observed on the western edge of the sun. Its base extended from + 37°4′to + 44° 58′ heliographic latitude. Another prominence was seen on August 18, at 11h. 45m., between – 41° 29′ and – 55°. This attained a height of 418″, but was of a much more broken character than the preceding one.—On certain kinds of surfaces, by M. Lelieuvre.—Researches on the atomic weight of fluorine, by M. Henri Moissan. (See Notes, p. 649.)—Action of aromatic amines and of phenylhydrazine upon the β-ketonic nitriles, by M. L. Bouveault. The author establishes the generality of the reaction—