ANALYTICAL GHEXISTRY. Analytical Chemistry. Examination of the Methods of Water-analysis. By F. TIEMANN (continuation. Deut. Chem. Ges. Ber. vi 1034-1051). THEmethods examined by the author are those which depend on:- i. The conversion of the nitric acid into ammonia in an alkaline solution (F. Schulze Chwp. Centr. 1861 657 833.-Wolf ibid. 1862 379.-Harcourt Chem. Xoc. J. xv 385.-Siewert Ann. Chern. Pharm. 293). ii. The reduction of the acid to nitric oxide and the reconversion of this into acid (Schlosing Awn,. Chim. Ph.ys. [3],. xl 479.-Reichardt Landw. Verszlchs-St. ix 14 150). iii. The reduction of the acid to nitric oxide and the volumetric estimation of the latter (Crum Amz. Chenz. Pharm. lxii 233.-Frank- land and Armstrong (Ihern. Xoc. J.,xx 67.-F.Schulze Zeitschr. anal. Chem. 1870 401). iv. The oxidation of indigo-solution by the acid (Marx Zeitschr. anal. Chem. 1868 412.-Trommsdorf ibid. 171.-Goppelsroder ibid. 1.V-n Bemmelen ibid. 1872 136.-Yinkener Rose’s Analyt. Chem. Sechste Aufl. ii 830 831.-Fischer J. pr. Chem. 1873 57). The method of Schulze in a modified form (of which description is ABSTRACTS OF CHEMICAL PAPERS. given) is preferred by the author to all others. The methods of Reichhardt and Trommsdorf are also strongly recommended ; the latter is a very useful one for approximate determinations. G. T. A. Estimation of Magnesium Manganese and Cobalt. By W. GIBBS(Chem. News xxviii 51). IFthe author’s method be followed of precipitating ammonio-magnesium- phosphate from a boiling solution microcosmic salt is a better precipitant than sodium phosphate and ammonium chloride.The results are accu- rate to 0.2 per cent. of the magnesium present if ammonium chloride be added before precipitation and ammonia after the liquid has cooled. Microcosmic salt gives good results also with manganese. Wohler’s method of separating cobalt from other metals consists in converting it into potassium cobalticyanide and precipitating the solu- tion of this latter with mercurous nitrate. This precipitation is best effected at the boiling heat with addition of mercuric oxide to remove a’ny nitric acid that might be present. The precipitate after wash- ing with hot water containing mercurous nitrate is then treated as Wohler directs.B. J. G. Reduction of Soluble Phosphate in Superphosphate. By C. U. SHEPARD, Jiinr. (Chem News xxviii 51-54; reprinted from the American Chemist). THE author brings together the results and theories on reduced phos- phate which have already appeared in the last volume of this Journal. He then shows their bearing on the value of superphosphate made from South Carolina phosphate. Fresenius’s ammonium citrate soh-tion dissolves & to -& of the phosphoric acid in South Carolina phosphate. It should be noted however that these experiments were made upon exceedingly fine dust. He gives no experiment with the phosphate as it is used in making superphosphate. Nor does he appear to have tried whether repented treatments of the same portion of sub-stance with ammonium citrate always dissolved the same quantity of phosphoric acid (see this Jourrial [23 ix SO).Some superphosphates made from the above phosphate the soluble and insoluble phosphates in which were determined soon after manufacture were again analysed after the lapse of a year the reduced phosphate being then also deter- mined. The amount of this last was always greater than the loss of soluble phosphate which appears to give support to the theory that the alteration of tribasic phosphate is one cause of reduction,. It must be noticed however t>hat no attempt was apparently made to dissolve anything by ammonium citrate in the so-called “ fresh ” sample. Moreover the excess of reduced phosphoric acid over the loss of soluble phosphoric acid is not really so great sometinies by one-half as it appears in the author‘s tables to be.The loss of soluble phosphoric acid is greater than is there stated since the loss of water by keeping the superphosphate must be taken into consideration. The paper con- cludes with a dewription of other changes which take place in super- phosphate when it is kept for some time. B. J. G. ANALYTICAL CHEMISTRY. Modification of Forbes’s r/lethod of Estimating Titanic A&. By W. BETTEL (Chem. News xxviii 93). THEfinely-powdered substance is fused with twelve times its weight of pure acid potassium sulphate. It is then digestedin cold water (about 300 C.C. to a gram of titanic iron ore) ; a~nd the solution filtered from silica is diluted with nine times its volume of water and treated with aqueous sulphurous acid till all the iron is reduced.It is then boiled for several hours the evaporating water being replaced. Titanic acid is thus srecisitated as a white sowder. which is washed with water containiig a tittle sulphuric acid and ignited as usual. B J. G. Separation of Chromium and Uranium. By W. GIBBS(Chem. News xxviii 63). WHENthe chromium esists in the mixture as chromate together with relatively small quantities of chlorides or sulphates and in the absence of any acid such as phosphoric which forms a mercury salt not easily volatilised the chromium is precipitated by Berzelius’s method with mercurous nitrate. This latter should be free from nitrite otherwise a reduction of the chromic acid will take place ; this was erroneously attributed in a former paper (Amer.Joacr. Xci. [Z) xxxix 5Y) to the cmployment of hot solutions. The precipitation is best effected at a boiling heat and the precipitate washed with a hot dilute solution of the nitrate. Precipitation with barium acetate with addition of alcohol also gives good results. Lead acetate gives a precipitate which passes through the paper. When chlorides or sufphates are present in large quantities the solution may be boiled with soda. The sodium uranate is filtered off washed with water containing soda redissolved in hydro- chloric acid and the uranium determined as usual. The chromium. in the filtrate can be precipitated by ammonia after reduotiou for which purpose an alkaline nitrite is preferable to alcohol since the time occupied in Foiling off the latter is saved.When the chromium is not present as chromate in the substance to be aualysed it is converted into sodium chromate by boiling with a slight excess of soda and then adding bromine-water. The small quantity of chromium which in this process is precipitated with the sodium uranate formed in the reaction is separated as described at the beginning of the paper. B. J. G. Direct Estimation of the Constituents of Carbon Compounds by One Combustion. By A. MITSCHERLICH (Deut. Chem. Gcu. Bey. vi,1000-1002). THEcompound is mixed with mercuric oxide and placed in a com-bustion-tube open at both ends. Before beginning the combustion a stream of pure nitrogen is passed through the tube.The carbon dioxide and water are weighed as usual the last traces being driven out in a stream of nitrogen. If nitrogen is present in the compound nitric oxide is formed which is retained in a weighed apparatus containing ABSTRACTS OF UHEMlCAL PAPERS. chromic acid and stannous chloride placed between the water and carbon dioxide absorption bulbs. By weighing the mercury after com- bustion the amount of oxygen used for the oxidation of the carbon and hydrogen is determined and by deducting this amount from that of the total oxygen and hydrogen contained in the carbon dioxide and water respectively the amount of oxygen in the compound is estimated. The mercury is weighed after subliming it into a small weighed tube ; if the compound contained chlorine bromine or iodine this subliniate must be dissolved and the halogen present estimated.Sulphur or phosphorus forms sulphuric or phosphoric acid. In such cases caustic potash is added after combustion to the residue in the tube and the resulting sulphate or phosphate of potassium analysed by the usual methods. M. M. P. 31. Presence of Cyanogen in Bromine. By J. L. PKIPSON (Chem. News xxviii 51). INthe manufacture of iodine a little cyanogen iodide is often produced. It would appear that an analogous bromine compound is formed in preparing commercial bromine since several samples of the latter even when warranted pure gave indications of cyanogen the amount of which was approximately estimated as follows.Iron filings equal in weight to the bromine employed were mixed with five times their weight of water and added slowly to the bromine with stirring. The liquid was rapidly filtered and in a few days it deposited the whole of its cyanogen asferricyanide of iron. This reactiou might be employed in testing with pure bromine for cyanogen in steel. B. J. G. Estimation of Hydrocyanic Acid in Bitter Almond Water By A. KOSTER (Arch. Pharm. [3],ii 510). THE author estimates the quantity of hydrocyanic acid in the pharma- ceutical preparation by Liebig’s method i.e. by the use of a standard solution of silver nitrate so prepared that if the almond water is of the pharmacopeia strength equal volumes of the water to be examined and of the standard silver must be used; if the standard water is too strong the amount of ordinary water that must be added to it to dilute it down to the right strength is thus found by inspection The Phay-macopEia Germanicn prescribes that 1000 parts of bitter almond water should contain 1of hydrocyanic acid ; hence the silver solution must contain 3.148 grams of silver nitrate AgN03 per litre ths titration method corresponding with the equation 2HCy + 2KH0 + AgNO3 = 2Hz0 + RNO3 + KCy.AgCy and the termination of the reaction being known by the production of a precipitate permanent on agitation; this is rendered much more evident if a little sodium chloride solution be used as indicator.C. R. A. W. TECHNICAL CHEMISTRY. The Separation of the Mixed Alkaloids from Cinchona Barks.By J. E. DE VSIJ (Pharm. J. Trans. [3] iv 241). TWENTY grams of powdered and sifted bark dried at looo are mixed with a milk of lime made of 5 grams of dry slaked lime and 50 grams of water. This mixture is slowly dried and then boiled with the strongest possible spirit used in successive portions of 200 c.c. 100 c.c. and 100 C.C. respectively. The liquid is filtered slightly acidulated with wettk sulphuric acid and the precipitated calcium sul- phate allowed to subside. The greater part of the liquid can then be poured off the rest fileered through a small filter and the alcohol recovered by distillation. The residual liquid with washings of the apparatus is poured into a capsule and heated on a water-bath till all the spirit is expelled then filtered from the mixture of quinovic acid and fatty substances which are deposited.The filtrate reduced to a small volume by evaporation is then whilie stiZZ warm precipitated by a slight excess of caustic soda. When the precipitated alkaloYd melts as is sometimes the case it must be powdered after cooling before col- lecting the precipitate on a filter. After washing with the smallest possible quantity of water the precipitate is drained on blotting-paper then detached from the filter dried and weighed. The amount of quinovic acid may be ascertained in the meantime by Creating the mixture of quinovio acid and fatty substances with a weak solution of caustic soda by which a great part of this mixture is dis- solved.If to this turbid solution a slight excess of chloride of calcium is added only the quinovate of calcium remains in solution and on filtering and acidulating with hydrochloric acid the quinovic acid is precipitated as a,bulky jelly. As the amount of,quinovic acid is generally very small its quantity can rarely be ascertained with accuracy unless the amount of bark be not under 40 grams. The author usually makes two determinations of the alkaloids on two portions of bark of 20 grams each ; these he unites for the estimation of the quinovic acid. W. A. T.