ABSTRACTS.
GENERAL AND INORGAN13 CHENISTRT. Molecular Weight of Iodine
ill
its Solntions. MORRIS
LOER. The fact is recalled that iodine dissolves with different colors in different liquids. For instance, the solution in ether is deep reddish brown, and that in carbon di-sulphide is pure violet. Obtaining, by an apparatus of special construction, the difference between the vapor-tension of the pure solvent, and that of the iodine solution ; the author establishes a formnla, giving a molecular weight for iodine corresponding to I, for its red solutions, and a valne between I, and T, for those of violet color. ( J . Chenz. P. M. SOC., 53, 505.)
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w.
ANALYTICAL CHEXISTRY. Determination of Sulphur in Coke. By L. BLUJI. The author found.on comparing different methods for the deter niination of sulphur in coke, that the fusion method was the only one giving reliable results. The finely pulverized coke should be fused with a mixture of 1 6 parts NaCl, S parts KNO,. 4 parts Na,CO,, and the mass, after fusion, dissolved in wator, etc., the snlphnr being weighed as barium sulphate. Oxidatioii of the sulphur in the coke by potassium chlorate and liydrochloric acid or bromine in hydrochloric acid, yielded only about 20-25 per cent. of the trne per cent. of sulphnr. (Zeit. m a l . Chern., 27,pp. 44.5-452.) J. F. G.
Determination of Carbon iii Iron. nr. 1;. L.
DE
KONINCE.
T o obviate any error arising from the possible generation of chlorine during oxidation with chromic acid in the carbon deter-
mination according to the JlcCreath-Ulgren method, the a u t h o r recommends the addition of il. sniali quantity of siirer sulphate. (Zeif.n i ~ n l .Chem.. 27, p . 464), J. F. ( i .
New Mixture for Sepnratiiig Carbon from Pig-iron, Steel, etc. T.W. Hocrc:. The usual method of procedure occasionally allows the precipitation of the somewhat insoluble cuprous chloride w i t h the separated carbon. T o prerent this precipitation, advantage is taken of the reaction Fe,CI, + Cu, CI,=2FeCl + BCuOl,. T h e weighed metal is placed in a beaker, covered with half an inch of CuCl, solution (Sp. Gr. 1.35), and then a considerable excess of Fe,C1, solution (Sp. Gr. 1.30) is added. After fire minutes stirring, heat is gently applied u p to the boiling point. Decomposition is complete in twenty minutes. Precipitation of basic compounds is prevented by addition of a few drops of HC1, and the carbonai?eous residue is filtered off. (Chem. Neics, 58, 2.99.) w. 1'. JI.
Qrralitative Separation of Gold and Platinum froni Arsenic, Antiiiiony and Tin. By Dr. L. 1,. I)E KOXINCKand Dr. A. LECREMIER. The moist sulphides of the metals contained in a small porcelain vessel, which is placed in a glass tube of 30 cm. length, are heated while subjected to a stream of hydrochloric acid gas, generated by the action of sulphuric acid upon solid ammonium chloride. The antimony and tin rapidly volatilize as chlorides and the arsenic as sulphide, leaving the gold and platinum in the residue. (Zeit. J. F. (i, rcnccl. Cht?m., 21, pp. 463.)
Use of Aiiiline as an Absorbent of Cyanogen in Gas I~ Analysis. J I O R K Lom. Cyanogen is readily absorbed by aniline with formation of HCK. The prescence of CO, causes an evolution of the HCN present, a t the same time a portion of the GO, passes into solution. Carbon monoxide acts in like manner. As the above gases are those which usually accompany cyanogen,
15 7
ABSTRACTS : ANALYTICAL CIIE,\IISTR17.
the use of aniline as an absorbent is not practicable. (J. Chew. W. I?. M. SOC., 63, 812.)
Chemical Examination of Gums and Resin% ROWLAND WILLIAMS. Eighteen different kinds were examined, and percentage determined of : Potash absorption ; Saponification equivalent ; Iodine absorbed ; Loss on drying ; Mineral matter. The results are tabulated. (CJheni. News, 68, 22.4.) W. P. M. Specific Gravity, at 100" F., of Fat when Clear, and also when Clouded with Crystals. E. W. T. JONES. Lard was melted until quite clear, and then the temperature was allowed to fall to looo F. A t this temperature the clear fat gave a specific gravity of 905.87. The melted fat was then maintained a t 100° F. for some hours until clouded with crystals. On again taking the specific gravity the result was 910.49. The determinations were made with the gravity bottle. (Analyst, 19, 201.) W. P. M.
Determination of Fat in Oil Cake. By R. KLOPSCH. T h e drying of linseed oil cake should be limited to three hours and conducted on the water bath. Ether will then readily extract the oil, and on evaporation leave i t as a residue having a yellowish green color, whereas, if overheated while drying, the oil residue has a more or less brownish color. ]hying a t temperatures over 100" 0, and even a t lower temperatures for too long a time, seems to oxidize some of the oil and render i t insoluble in ether. (Zeit. anal. Chem., 2 7 , p p . 452-467.)
J. F. G.
The Chemical Character of Peptones and the Separation of Pure Albumen from the same. By R. PALM. Peptone is the result of the action of lactic acid upon egg, milk, ser-albumen, or casien, and further, peptones are similarly produced from gelatin, fibrin, and chondrin. Peptone is a solution of protein in lactic acid. By adding ether to an alcoholic solution of peptone, a peptone of uniform composition is separated as an oily mass containing, protein and lactic acid in exact stoichomtttric proportions. Vice versa, pure albumen can be separated from peptone after neutralizing the lactic acid of t h e peptone solution
h y ;immoiiia, and adding an excess of 9.5 per ccnt. alcohol, whereby dl the albumen is precipitated. -~lcolio1acidulated w i t h sulpliuric acid will also precipitate the albiinieii, i f tlie sulpliuric acid is not in too large excess. T h e :LU thor found that when a peptoiie solution was neutralized ity ammonia. all the albnmen reagents gaye the reactions characteristic of pure nomial aIl)iinien, ant1 that the albimeii was also c.o:ipul:ible 1)y heat. l’eptonc. as a result of digestion, may curitaiii lactic and hydrocliloi~icacid. F r o m a solution of peptone the coagulation of t h e i\lhnnie~ibv heat, or 1)reeipitatioii by alcohol, is prm-ented by the presence of the lactic acid. I’eptoiie reduces itii a1k;Lline copper solution as readily as milk sugar. Altliotigli peptoile is a solution of protein (albumen) 111 lactic, acid. tlic term i r also applicable to solntians of protein in othe:. i ~ ~ ~such t l s as hytlrocliloric, snlphnric and acetic acid. To distinguish all)uniun from peptone potassiuni xanthogennte niay lie used, it precipitates solutions of peptone a t oiice. and normal solutions of albumen only after acidulation. (Zeit. cinal. ,I. F. (;. f 3 e n z . , 27, ,?.i
