Atomic Weight of Oxygen. By E. W. MORLEY (Amer. Chem. J., 10, 21-26). It is pointed out that the conclusion drawn by Scott (this vol., p. 411) as to the ratio in which hydrogen and oxygen combine is not warranted by his experimental method, more particularly because the amount of impurities in the hydrogen and in the oxygen used were not separately estimated. Methods are proposed by which these impurities can be estimated and allowed for, and also new methods for effecting the synthesis of water in the most exact H. B. manner. Oxidation of Solutions of Sulphurous Anhydride and Sulphites. By I. A. BACHMAN (Amer. Chem. J., 10, 40-41).-Solutions of normal potassium, sodium, and ammonium sulphites were completely oxidised in three weeks, whilst sulphurous acid had lost by volatilisation and oxidation three quarters of its strength, and acid ammonium sulphite had only lost about 45 per cent. All the solutions contained 10 grams of sulphurous anhydride per litre, were kept in open bottles, and shaken twice daily. H. B. Sulphites. By A. RÖHRIG (J. pr. Chem. [2], 37, 217-253).— The author has revised the work of Muspratt (Annalen, 50, 259), Rammelsberg (Ann. Phys. Chem., 67, 245), and others, and has fully described the sulphites of lithium, thallium, the alkaline earths, lead, magnesium, zinc, cadmium, aluminium, uranium, bismuth, iron, chromium, manganese, nickel, cobalt, and tin, with the result, in general, that the older observations are confirmed. Attempts to obtain the two isomeric salts NaSO, OK and KSO, ONa were not successful, only one potassium sodium sulphite being formed under any circumstances. G. T. M. Simple Formation of Thiosulphates. By E. DONATH and F. MÜLLNER (Dingl. polyt. J., 267, 143).—This method is based on the oxidation of metallic sulphides in aqueous solution by boiling with manganese dioxide. D. B. New Sulphur Oxy-acid. By A. VILLIERS (Compt. rend., 106, 851-853). Sodium thiosulphate is mixed with a quantity of water insufficient for complete solution, and the mixture is saturated with sulphurous anhydride. If any salt now remains undissolved more water is added, and the mixture is again saturated with the gas. A yellow solution is obtained, and if this is evaporated immediately in a vacuum, it evolves sulphurous anhydride, and, if the temperature does not exceed 0°, only sodium thiosulphate is obtained from the residue. If the solution is allowed to remain at the ordinary temperature for two or three days, it will then absorb more sulphurous anhydride, and if after saturation it is allowed to remain for a day or two and is then evaporated in a vacuum over sulphuric acid, it yields brilliant, white, brittle, anhydrous prisms of the composition Na2SO ̧. When these crystals are dissolved in water and evaporated as before, the hydrate Na2SO, + 2H2O is obtained in soft, waxy crystals arranged in nodules. If the mother-liquor from the first crystals is concentrated, it yields small crystals of the trithionate Na2SO. + 3H2O, which has not previously been crystallised. The formation of these salts is represented by the following equations:-2Na2S2O3 + 5SO2 = 2Na2SO ̧ + S and 2Na2S2O3 + 3SO2 = 2Na2SO + S. At a low temperature very little sulphur is actually liberated, and it seems to unite with the thiosulphate, forming a salt of the composition Na2SO3. The salt Na2SO, may be regarded as a derivative of dithiopersulphuric acid, H2O,S,O,,Š2. C. H. B. Formation of Crystallised Selenates in the Dry Way. By L. MICHEL (Compt. rend., 106, 878-881).—The selenates described were prepared by fusing the chloride of the particular metal with an alkaline selenate and some sodium chloride, cooling very slowly, and extracting with water. The insoluble residue is a mixture of crystals with a crystalline powder, and if the latter is mixed with sodium chloride and heated until the greater part of the solvent is volatilised, crystals several millimetres in length are obtained. Barium selenate forms colourless or bluish-white crystals with a vitreous lustre; hardness 3 to 4; sp. gr. 475. They are rhombic octahedra elongated along the greater diagonal, and are frequently arranged in groups parallel with h'. In form and optical property, they are identical with barytes. Strontium selenate forms rhombic prisms of sp. gr. 4-23, closely resembling the crystals of celestine from Lake Erie, and precisely similar to celestine in crystallographic and optical properties. Calcium selenate forms colourless or milk-white rectangular lamella of sp. gr. 2-93; hardness 35. It melts before the blowpipe without exfoliation, and is only slightly soluble in water or nitric acid. Hydrochloric acid attacks it slowly with evolution of chlorine. Optical examination shows that its properties are very similar to those of anhydrite. Lead selenate cannot be obtained in the same way, but a mixture of the amorphous selenate, lead nitrate, and sodium nitrate yields small rhombic prisms with all the characters of anglesite. Measurements of the angles of the crystals, &c., are given in the paper. From the results it follows that the artificially prepared anhydrous selenates of barium, calcium, strontium, and lead, are isomorphous with one another and with the corresponding natural sulphates. C. H. B. Arsenic Nitride. By I. A. BACHMAN (Amer. Chem. J., 10, 42— 44). When a tube containing silver cyanide and arsenious oxide is heated at 300-400°, a dark-brown substance is formed as a coating over the arsenious oxide crystals. The mixture contains about 2 per cent. of nitrogen with only a trace of carbon, and is probably the hitherto unknown arsenic nitride. H. B. Decomposition of Ammonium Chloride by Phosphoric Acid. By K. W. JURISCH (Dingl. polyt. J., 267, 424-431).-The author has investigated Witt's process (Ger. Pat. 34395, May, 1885) for the preparation of hydrochloric acid, and ammonia from ammonium chloride by decomposition with phosphoric acid. The method is intended to replace the troublesome distillation of the mother-liquors by means of lime, and to recover the chlorine lost in the calcium chloride. The separation of the ammonium chloride is effected either by evaporation to dryness and sublimation, or by fractional crystallisation. The author found that of 12 mols. of phosphoric acid employed, 8 mols. are taken up and 4 mols. remain as free acid, half being orthophosphoric acid, the remainder pyrophosphoric acid. In order to complete the decomposition at a low temperature without volatilising the ammonium chloride, an excess of phosphoric acid is required, hydrochloric acid only being expelled. On subsequently increasing the temperature, from 63 to 86 per cent. of ammonia is given off. The residue which consists of metaphosphoric acid with some ammonium metaphosphate may be used for the decomposition of a fresh portion of ammonium chloride, so that it is possible to decompose ammonium chloride in succession by the same quantity of phosphoric acid without loss of acid. Owing to the difficulty of obtaining a material for lining the furnace or other vessel capable of resisting the action of fused phosphoric acid, the application of the process on a large scale has hitherto been impossible. According to Brunner, Mond, and Co., even platinum is so energetically attacked by the acid that it cannot be employed for the heating vessel. D. B. Oxidation of Silver. By H. LE CHATELIER (Bull. Soc. Chim., 48, 342-345).-When pure precipitated silver is heated in oxygen at 300° under a pressure of 15 atmospheres it is slowly oxidised. The oxidation could not be completed, and the largest amount of silver oxidised was 50 per cent. The decomposition of silver oxide at the same temperature was found to be extremely slow; the pressure increased for three days, and then remained constant at about 10 atmospheres. The tension at which the oxide decomposes at 300°, is, therefore, between 10 and 15 atmospheres. At 400—450° silver oxide decomposes rapidly. N. H. M. Alloys of Calcium and Zinc. By T. H. NORTON and E. TWITCHELL (Amer. Chem. J., 10, 70-72).-Following the directions. of Caron (Compt. rend., 50, 547) calcium chloride, zinc and sodium were heated together, but the alloys obtained did not contain more than 23 to 64 per cent. of calcium, instead of 10 to 15 per cent. as reported. The poorest alloy melted at 360°, the same temperature as zinc, but it is remarkable that the richer alloys melted at as high a temperature as 640°. They do not decompose water, or oxidise at ordinary temperatures in the air, and the zinc cannot be removed by volatilisation in a current of hydrogen without losing considerable quantities of calcium. H. B. Action of Metallic Oxides on Solutions of Zinc and Manganese Chlorides. By G. ANDRÉ (Compt. rend., 106, 854-856).The finely divided oxides were heated or boiled with water and zinc chloride until they were completely dissolved, or until no further change was observed, and the solutions were slowly cooled. Zinc chloride and yellow mercuric oxide yield the white, amorphous zinc oxychloride, 2ZnCl2,3ZnO + 11H,0, which when washed with alcohol and dried on paper, changes to ZnCl2,4ZnO + 6H2O. It is remarkable that mercuric oxide yields only a zinc oxychloride, since with magnesium chloride it forms a double oxychloride (Abstr., 1887, 446 and 447). Lead oxide and zinc chloride yield brilliant, white, slender needles, which contain an almost constant proportion of chlorine, whilst the proportions of lead and zinc vary. In most cases, they are a compound of ZnCl2,3ZnO with ZnCl2,PbO. The latter compound may be regarded as lead oxychloride in which the zinc lead chloride has been replaced by the zinc salt. Cupric oxide and zinc chloride yield a green powder of the composition Zn,Cu¿Cl ̧O + 6H2O, or supposing it to be derived from the well-known oxychloride, ZnCl2,3ZnO, it may have the constitution (ZnCl2, ZnO,2CuO) (ZnCl2,3CuO) + 6H2O. Cupric oxide and manganese chloride produce an apple-green powder, MnCl2,3CuO + 3H2O, which may be regarded as the unknown oxychloride, MnCl2,3MnO, in which cupric oxide has replaced manganous oxide. It is not affected by boiling with a solution of manganous chloride. Lead oxide and manganese chloride yield lead chloride only, but if the mother-liquor is poured into cold water, the compound 2PbCl2,2PbO + 3H2O, is obtained as a flocculent precipitate. Attempts to obtain ammoniacal oxychlorides in which the base of the oxide was different from the base of the chloride were unsuccessful. C. H. B. Supposed Dissociation of Zinc Oxide: Condition of the Atmosphere within a Platinum Vessel heated by a Gas Flame. By H. N. MORSE and W. M. BURTON (Amer. Chem. J., 10, 148–153). -When zinc oxide is heated for many hours in platinum vessels in a muffle furnace to a temperature above the melting point of steel, it does not lose weight, nor is the crucible in any way altered; but when heated over a gas-lamp or blowpipe there is a constant loss of weight, as has been noticed by Erdmann and by Marignac, who ascribed the loss to dissociation of the oxide. The explanation is, however, disproved by the above stated behaviour of zinc oxide in a muffle furnace, and by the fact that the atmosphere within a platinum vessel strongly heated by a gas flame always contains free hydrogen, which reduces the zinc oxide. The hydrogen is produced by the dissociation of the water produced in the cooler parts of the flame, and is then occluded by the platinum, and so passes through the crucible. A platinum tube connected with a gas burette, the whole holding 130 c.c. of air, was heated with a blast-lamp for 1, 2, 3, and 4 hours, when 54, 88.5, 98·1, and 100 per cent. of the oxygen of the confined air disappeared, and in the last two cases, moreover, 24 and 27 c.c. of free hydrogen were present, so that at least 228, 44, 445, and 482 c.c. of hydrogen must have passed through the platinum. This amount is increased from 228 c.c. to 285 c.c. by slightly diminishing the internal pressure by 30 mm., and is decreased to 209 by increasing the pressure by the same amount. Similar results were obtained by using an ordinary bunsen burner. In all cases only the outer or oxidising flame was allowed to touch the tube. The bearing of these facts ou the ignition of precipitates in platinum vessels is obvious. H. B. Colloidal Cadmium Sulphide. By E. PROST (Chem. Centr., 1888, 32, from Bull. Acad. Bely. [3], 14).-Colloidal cadmium sulphide can be prepared by completely precipitating an aminoniacal solution of cadmium sulphate with hydrogen sulphide, washing the sulphide with water by decantation, suspending the precipitate in water, and submitting it to a slow stream of hydrogen sulphide, the precipitate becomes first flocculent, then milky, and finally disappears entirely. The solution is then boiled until lead paper shows the absence of hydrogen sulphide. The solution is a beautiful goldenyellow by transmitted and fluorescent by reflected light. The composition of the dissolved substance is Cds. Dilute solutions remain unchanged for a long time. A solution containing 4 grams of sulphide to the litre remained clear many days, but another solution containing 11 grams to the litre coagulated in 24 hours. The following are the results of experiments on the coagulation of the colloidal sulphide. The (1.) There is no relation between the molecular weight of acid and salt and their coagulating activity. (2.) The coagulating power of salts is determined by the metal they contain. The greater the valency of the metal they contain, the greater their energy. influence of the acid is generally not marked. Potassium sulphate coagulates in dilutions of 1 in 1666 parts, aluminium sulphate in dilutions of 1 in 232,558 parts. (3.) Among the alums, those of the triad metals are most active. (4.) The coagulating power of acid salts appears to be greater than that of normal salts. (5.) Cadmium salts are very active in coagulating the sulphide, 1 part in 250,000 of cadmium sulphate and I part in 285,714 of cadmium nitrate sufficing. Most of these results agree with Schulze's results with arsenic and antimony sulphides. The concentration of the colloidal sulphide is without influence on the manner in which it coagulates. J. P. L. Action of Heat on Oxides and Salts of Manganese. By A. GORGEU (Compt. rend., 106, 743-746).-Anhydrous manganous oxile heated rapidly and strongly yields the red oxide, but if care is taken to avoid incandescence, and the oxide is heated to dull redness until its weight is constant, the sesquioxide is obtained. The oxida tion at 200° to 430° of the manganous oxide prepared at a high temperature ceases with the formation of the oxide MnO2,4MnO, but if the manganous oxide was prepared at a dull red heat and is oxidised for the same time below 430° it yields a higher oxide, which, however, contains less oxygen than the sesquioxide. The action of air at 200-430° on manganous oxide prepared below 400° could not 2 x VOL. LIV. |
