Inorganic Chemistry.
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ganate method for reducing sugars the number of grams of permanganate used be stated ; and ( 7 ) that the Creydt method for the determination of sucrose and raffinose be adopted provisionally.
INORGANIC CHEMISTRY. HENRYFAY,REVIEWER.
On the Color of Compounds of Bromine and Iodine. BY J. H. KASTLE. Am. Chem. J., 21, 398-413.-The color of the compounds of the halogens is discussed, and it is shown that the power of producing color increases from fluorine fo iodine. I t is shown that the compounds having the least color are most stable, while the colored compounds are usually easily decomposed, giving rise to colors which are similar to the color of the halogen in the free state. On heating a colored compound the intensity of the color is increased and the reverse process takes place on cooling. T h e author assumes that in colored conipounds there is slight dissociation of the solid substance, the color being d u e to small quantities of the free halogen. T h e property of color in the halogen compounds is supposed to be an additive and not a constitutive property. Examples of a large number of inorganic and organic halogen compounds are given. Among the aromatic organic compounds it is shown that the color varies with the stability of the compound. Substitution of halogens in the benzene ring produces stable compounds, and they are usually colorless, while the side-chain substitution products are usually colored and are more unstable.
The Action of Ammonia and Amines on Chlorides of Silicon. BY FELIXLENGFELD.A m . Chem.J., 21, 531-53j.-On bringing together benzene solutions of ammonia and silicon tetrachloride, silicon tetramide, Si(NH,),, is formed. This substance breaks down, rapidly with water and more slowly in t h e air, with lossof ammonia into silicon diimide, Si("),. I t had generally been believed that the product of the action of ammonia on silicon tetrachloride was the compound SiC1,.6NH,, but the author considers it a mixture of silicon diimide and ammonium chloride, the composition of the mixture being represented by the formula S i ( NH),.4NH,Cl. Silicon tetrethylarnine is a colorless oil that does not solidify in a freezing-mixture. It keeps indefinitely in closed tubes, is decomposed by water, and boils a t 102' under a pressure of 2 0 mm. The Action of Chromic Acid on Hydrogen. BY CHAS. L. REESE. A m . Chem. I., 22, 158-164. Hydrogel1 is oxidized by a saturated chromic acid solution in presence of a porous ma-
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Review of Americaz Chemical Researrh
terial like platinized asbestos, burnt clay balls or balls made of gypsum, but pure chromic acid does not oxidize hydrogen even in the presence of considerable quantities of sulphuric acid. T h e oxidation of hydrogen takes place a t and above 61" when heated for a sufficient length of time ; but a t j o o the absorption is very slight, even after two hundred and eighty-eight hours, and a t 40' there is no oxidation. Saturated solutions of chromic acid evolve oxygen freely at 119" and above. and as hydrogen is oxidized at temperatures below those at which oxygen is given off, t h e oxidation of hydrogen seems not to be dependent upon the evolution of oxygen from chromic acid by heat. Electrolytic hydrogen produced by passiiig a current through a chromic acid solution, is u o t oxidized b!- pure chromic acid, but is readily oxidized in the presence of other substances. When sulphuric acid or sulphates are added, oxidation takes place up to a certain limit, depending upon the percentage of sulphuric acid, and then ceases entirely.
Dehydration of Crystals of Sodium Phosphate. BY T. C. WHITLOCK A N D C. E. BARFIELD. Airt. Chem.]., 22, 214-215. T h e water of constitution of disodium hydrogen phosphate begins to be lost at 230' ; below this temperature water of crystallization may be determined. Solubility of Lead Sulphate in Ammonium Acetate. By J. C. I,o?;G. Am. Chew.].. 22, 217-218.-Approximate values of the solubility of lead sulphate in ammonium acetate solution are given. Classifications of the Carbides : Their nodes of Formation and Reactions of Decomposition. BY J. A . MATHEWS. J . Am. Chem. Soc., 21, 64j-6jo.-The author has classified the carbides according to their arrangement in the periodic system, their decomposability by water, their reaction with t h e halogens or halogen acids, and their behavior toward heat and oxidizing agents. T h e different methods of preparatiou and the products of decomposition which serve as a means of classification, are given. Preparation of Graphitoidal Silicon. BY FREDERICK S. HYDE. J . A m . Chem. SOL.,21, 663-66j.-The method depends upon the reduction of finely pulverized white sand with magnesium powder and the subsequent fusion of the reduction-product with cryolite and aluminium, thus forming an alloy of alumini u m and silicon, from which the latter is obtained on treatme%t with hydrochloric acid.
Biological Chemistry.
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Action of Hydrochloric Acid Gas upon Sulphates, Selenates, Tellurates, and Phosphates. BY RAYMOND W. TUNNELL AND EDGAR F. SMITH. J . A m . Chem. SOC.,21,gzg-g3z.-Hydrochloric acid completely removes selenium and tellurium from the mixture of selenic or telluric acids with phosphoric acid, but will not separate these elements from sulphuric acid, some of the latter always being carried over. I t was found that dry hydrochloric acid passed over dry potassium sulphate in the cold, combined with the latter, and the product formed maintained its composition at rjo0 and did not lose in weight when kept over soda-lime in a vacuum desiccator for fifteen hours. When dry potassium sulphate was heated in dry hydrochloric acid gas from 200' to a dull red heat, sulphuric acid was found in the receiver, while the substance remaining behind after this treatment weighed more than the original substance. The Precipitation of Copper by Zinc. BY J O H N C. SHENEDGAR F. SMITH.J . Art. Chem. Soc., 21,g3z-g33.-T h e precipitation of copper by zinc was found to give fair quantitative results, b u t some zinc was always found in the copper. GLE A N D
The Persulphates of Rubidium, Cesium, and Thallium. ARNOTTR . FOSTER A N D EDGAR F. SMITH.J . A m . Chem. SOC., 21, g34-g36.-These salts were prepared by electrolyzing a mixture of two parts sulphuric acid (sp. gr. 1.35) with one part of a saturated solution of the sulphate. I t was impossible to isolate t h e thalliuni persulphate on account of its great solubility and the rapidity with which it decomposed i n the air. BIOLOGICAL CHEMISTRY. A . G. WOODMAN. REVIEWER.
Saw Palmetto. B Y p. L. S H E R M A N A N D c. H. BRIGGS. Pharm. Archives, 2, 101-1 16.-The oil extracted by pressure from the fruit of the saw palmetto and also that expressed from the nuts were examined in order to ascertain their composition. T h e oil obtained from t h e pulp of the fruit was distilled under reduced pressure and found to consist of caproic, caprylic, capric, laliric, palmitic, and oleic acids and their ethyl esters, about 62 per cent. of the oil being free acids and 37 per cent. esters. T h e oil of the nuts contained only 2.3 per cent. free acids, the greater part of it being the glycerides of the same acids as the pulp oil with the addition of stearic acid and without the caproic acid. No alkaloids were found and the fruit was found to contain 5.4 per cent. of invert sugar.
