70 ABSTRACTS OF CHEMICAL PAPERS. Analg tical Chemistry. A Convenient Form of Graduated Flask. By WILHELM WISLICENUS (Bey., 1896, 29, 2442--2445).-The author points out that Biltz's modified measuring flask (Abstr., 1896, ii, 671) is not new, he has himself for several years used a modification in which the neck of the flask is widened above the ordinary graduation mark and again constricted higher up, a second graduation mark being placed above the wider portion so that this contains exactly 100 C.C. between the two marka. In the preparation of a standard solution, 1100 C.C. are first prepared of slightly greater strength than is required. A portion of the liquid is then removed from the upper part of the flask, its strength accurately determined, and from this the amount of water to be added to 1000 C.C.is calculated. The flask is then emptied by means of a pipette down to the 1000 C.C. mark and the requisite amount of water added. A. H. NorE.-This arrangement is identical with that described by Giles (Abstr., 1894, i, 25 l).--E~s. Iodometric Estimation of Selenious and Selenic Acids. By JAMES F. NORRIS and HENRY FAY (Amsr. C'hern. J., 1896, 18, 703- 706).-Selenious acid may be estimated by mixing a measured portion of the solution containing it with ice-cold water and 10 C.C. of hydrochloric acid (sp. gr. 1.1 2), adding an excess of N/10 sodium thiosulphate solu- tion, and titrating back with iodine solution. One mol. of selenious acid is equivalent to 4 mols. of sodium thiosulphate. The exact nature of the chemical change has not yet been ascertained.TheANALYTICAL CHEMISTRY. 71 hydrochloric acid must be sufficient to liberate all the thiosulphuric acid. Before applying this method, the selenic acid is reduced by adding 25 C.C. of concentrated hydrochloric acid to a measured portion of the solution, diluting to 100 C.C. and boiling for one hour, care being taken that the volume is never less than 75 C.C. The cooled liquid is then treated as described above, except that it will probably be already sufficiently acid. A. G. B. By FRANK A. GOOGH and A. W. PEIRCE (Amel.. ,J. Sci., 1896 [4], 1, 181--185).-The fact that selenium bromide is volatile, whereas tellurium bromide is not, can be made use of in estimating selenium in the presence of tellurium. With the object of testing the accuracy of the method, the author has experimented in the following way.Solutions containing known weights of selenious and tellurous anhydrides, dissolved in potash, were treated with excess of phosphoric acid in order t o dissolve the precipitate which was formed at first. One gram of potassium bromide was added, and the whole introduced into a Voit flask and water added to make the volume up to 50 C.C. ; this first flask was fused to a second Voit flask containing 10 C.C. of water, and the second flask, in its turn, was fused to a Drexel bottle which had fused to its escape tube a Will and Varrentrap bulb to serve as a trap. The bottle and bulbs were filled with potassium iodide solution, and car- bonic anhydride was kept slowly passing through the whole apparatus.The distillation of the products in the first flask was continued until the 50 C.C. had been reduced to 15 C.C. ; by thistime all the selenium had passed over in the form of its bromide and had been collected in the second flask, a small quantity of iodine had also been liberated in the bottle owing to bromine having passed over, As a quantity of selenium bromide collected in the tube connecting the two flasks, it was necessary to drive this over into the second flask before disconnecting. The first flask was then removed, 1 gram of potassium iodide was added to the second flask, the current of carbonic anhydride was again started through the apparatus, and the mixture was boiled for 10 mins. The free-iodine in the flask, Drexel bottle and trap was taken as the measure.of the selenious anhydride present. The results were fairly good, the errors being 0-1-0.7 per cent. Separation of Selenium from Tellurium. J. J. 8. Estimation of Tellurium by Precipitation as the Iodide. By FRANK A. GOOCH and W. C. MORGAN (Anzeli.. J. Xci. [a], 2, 271- 272, and Zeits. ccnoyg. Chenz., 1896, 13, 169-1’71).-Tellurous acid may he very accurately estimated by simply adding standard solution of potassium iodide as long as it forms a precipitate. The liquid should contain at least one-fourth of its bulk of stroag sulphuric acid, and when the greater part of the tellurium iodide has formed the beaker must be rotated to make the precipitate settle. More potassium iodide is then added to complete the reaction. Ten test experiments are given to show the accuracy of the process. L.DE K. Nitrates in Water. By ALESSANDRI and GUASSINI (Chem. Cerztr. 1896, i, 329; from Boll. Clhn. ,fama. 1895, 490).-A few C.C. of the72 ABSTRACTS OF CHEMICAL PAPERS. sample is evaporated to dryness, and 6 drops of a saturated solution of phenol in hydrochloric acid is at once added. Sometimes it is advisable to slightly warm the reagent. If nitrates are present, a reddish-violet coloration is obtained which on adding ammonia changes to an emerald green. L. DE K. Iodometric Method for the Estimation of Phosphorus in Iron. By CEARLOTTE FAIRBANKS (Amer. J. Sci. [4], 2, 181-185, and Zeits. ccnorg. CTwm., 1896, 13, 117--120).-The method for titrating molybdic acid with iodine recommended by Gooch and Fairbanks (this vol., ii, 76) is also applicable to the yellow molybdic precipi- tate, and is, therefore, a convenient process for the estimation of phos- phorus in iron, Twelve mols.of molybdic acid correspond with 1 atom of phosphorus. L. DE K. Estimation of Phosphates in Precipitates. By THEODOR PFEIFFER (Landw. Versuchs-Stat, 189 6, 47, 357-360).-Deterrnina- tions of phosphoric acid in a sample of precipitate gave the following results. With strong hydrochloric acid as solvent, P205 = 30.96 and 31.10 per cent. ; with aqua regia P20, = 33.00 and 32.91 per cent. ; with a mixture of sulphuric and nitric acids P20, = 33.19 per cent. It was found that the whole of the phosphoric acid in hydrochloric acid extracts is not precipitated by magnesia mixture (citrate method), and t h a t the filtrate yielded a further amount (2.27 per cent.), when boiled with sulphuric or nitric acid.This seems to be due to the presence of pyrophosphate in the precipitate. Whan pure monocalcium phosphate (5 grams) was heated for a long time at 250°, dissolved in boiling hydrochloric acid, and diluted to 250 c.c., 62.64 per cent. of P20, was found by direct precipitation, and 68.99 per cent. after boilimg with nitric acid. Two samples of precipitate (one of which had been slightly dried and the other not at all) were found to be free from pyrophosphate. Another sample which had been dried by heating with steam showed a distinct amount of pyrophosphate; whiIst a fourth sample from England, which had been over-dried, gave a percentage of 31.10 of P,?, before, and 32.91 after the ‘‘ inversion ” of the hydrochloric acid solution.The results show that mere estimation of total phosphoric acid is misleading, especially when aqua regia is employed as the solvent. N. H. J. M. The Precipitation of Phosphomolybdate in Steel Analysis. By GEORGE AUCHY. (J. Amer. Chern. Xoc., 1896, 18, 170--174).-1n order to ensure the complete precipitation of the phosphorus, the following process is recommended :--Two grams of steel is dissolved in 100 C.C. of nitric acid of sp. gr. 1.13, the solution is partially neutra- lised by adding 15 C.C. of strong ammonia previously diluted with 50 C.C. of water, and after heating to 8 5 O , the phosphoric acid is pre- cipitated by adding 60 C.C. of Blair and Whitfield’s molybdate solution. If it is thought desirable to precipitate from a very acid solution,ANALYTICAL C'H EMISTRY.73 from 18-20 grams of ammonium nitrate should be first added and the liquid should be somewhat diluted. The author adds a caution as t o thLoccssional presence of phosphoric acid in the reagents used. L. DE K, Interaction of Chromic and Arsenious Anhydrides. By PRILIP E. BROWNING (Amev. J. Sci., 1896 [4], 1, 35--37).--Kessler has shown (Pogg. Annnlen, 1855, 95, 204) that arsenious anhydride may be estimated by treating it in the presence of hydrochloric acid with an excess of a chromate of known strength. The excess of chromic acid is then determined by the addition of a ferrous salt until a drop taken from the solution gives a blue colour with a ferri- cyanide. Chromic acid is again added until the blue colour dis- appears.The author shows that a somewhat similar method may he used for estimating chromic acid. The chromate solution is mixed with about 10 C.C. of dilute hydrochloric or sulphuric acid (1 : 4) and a carefully measured amount of N/lO arsenious acid solution is run i n ; care must be taken t'hat the arsenious acid is in excess. It is not necessary to apply heat to bring about the reduction of the chromate. About 5 grams of potassium or sodium hydrogen carbonate are added to the solution, and in most cases a precipitate forms unless Rochelle salt has been previously added, N/lO iodine is then run in until the solution acquires a slightly permanent yellow colour, and the mixture is allowed to stand for about 30 minutes. The excess of iodine is destroyed by N/lO arsenious acid, starch is added, and the solution titrated with N/10 iodine.The points to notice are that the addition of Rochelle salt gives a dark green solution and thus renders it difficult to detect the point where the iodine gives the blue colour with starch. I f Rochelle salt is not added, a precipitate forms, and this contains small quantities of arsenious acid unless it is allowed to remain for some time (1-2 hours) with the excess of iodine. The method is fairly accurate, and can be carried out in the presence of ferric salts. J. J. S. By VICTOR PLANCHON and VUAFLART (J. Pha~m., 1896 [61, 4, 49--51).-The amount of borax present in a sample of butter can be roughly esti- mated by means of a colour reaction, depending on the formation of a blue compound produced by the fusion of copper oxide with borax. The ash from 20 grams of butter is fused with 0.5 grams of potassium car- bonate, and a trace of copper oxide.The amount of borax present may be estimated approximately from the intensity of the blue colour produced. M. W. T. By LIEBRICH (Chm. Centr., 1896, i, 68-69 ; Xtahl u. Eisem, 15, 1058).-The filter containing the silicic acid, silicon, and graphite is, without removing the iron, burnt, and the black ash is fused with dehydrated potassium hydrogen sulphate until all the carbon has disappeared. The residue, on being digested with hydrochloric acid, leaves pure silicic acid free from Detection and Estimation of Borax in Butter, Estimation of Silicon in Pig Iron. titanium and iron.L. DE K.74 ABSTRACTS OF CHEMICAL PAPERS. Detection and Estimation of Carbonic Oxide in Air. By JOHN S. HALDANE (J. Plqsiol., 1896, 20, 521--522).-The method previously described for estimating the percentage of carbonic oxide in the air by means of a solution of blood requires modification in view of the fact that daylight has a marked influence on the stability of carboxy-haemoglobin. The precautions to avoid the influence of strong light, and the necessary alterations in the table are given. W. D. H. Separation and Identification of Potassium and Sodium. By D. ALBERT KREIDER and J. E. BRECKENRTDGE (Anze~. J. Sci., [4], 2, 263-268, and Zeits. ccno~g. Chern., 1896, 13, 161-168. Compare Abstr., 1895, ii, 444).-Potassium may be completely separated from sodium by evaporating the solution with perchloric acid and treating the residue with 97 per cent, (commercial absolute) alcohol, which soon dissolves the2 sodium compound, but leaves the potassium per- chlorate which is quite insoluble.When dealing with a sulphate, this must first be decomposed by means of barium chloride, the excess of the latter being removed by ammonium carbonate, and the ammonium compounds expelled by ignition. The sodium is precipitated from its alcoholic solution as chloride by means of a current of hydrogen chloride, and may then be further identified. The perchloric acid must, of course, be quite free from sodium, and is, therefore, best purified by distillation under low pressure. Details for the safe Volumetric Estimation of Alkali Hydroxides containing Carbonates and of Alkali Carbonates : The Value of Phenol- phthalein and Methyl-orange as Indicators.By FBIEDRICH W. KUSTER (Zeits. unwg. Chem., 1896, 13, 127--150).-The only method for the volumetric estimation of mixed solutions of alkali hydroxides and alkali carbonates which gives trustworthy results is that published by C1. Winkler. The alkali carbonates are precipitated by barium chloride, and the solution, together with the precipitate, is titrated, using phenolphthaleln as indicator. The total alkali is determined by titration, using methyl-orange as indicator. Methyl-orange is, con- trary to the statements of previous authors, strongly coloured by carbonic acid; and in the titration of alkali containing carbonates the titration must be continued only to a known normal coloration which is defined by comparison with an equally concentrated aqueous solution of the methyl-orange saturated with carbonic anhydride.Phenol- phthalek is also coloured by aqueous solutions of alkali hydrogen carbonates when these solutions are dilute. The coloration is weakened by the presence of sodium salts of strong acids and by carbonic anhydride, and disappears entirely in the presence of large quantities of free carbonic anhydride. This indicator cannot, therefore, be used for the direct volumetric estimation of alkali hydroxides contained in alkali carbonates. Trustworthy results are obtained only when a small quantity of carbonate is present, whereas by Winkler's method the results can be depended on irrespective of the amount of carbonate.In the presence of hydrogen alkali carbonates, the total alkali is determined with methyl-orange as indicator ; the hydrogen carbonate preparation of the reagent are given. L. DE K.ANALYTICAL CHEMISTRY. 75 is estimated by adding a measured quantity of alkali hydroxide in excess, precipitating with barium chloride, and titrating, using phenol- phthalein as indicator. The difference between the amount of alkali added and that found after precipitation gives the quantity of hydrogen carbonate present, The results obtained are too low, and the error is pro- portional to the amount of hydrogen carbonate present. Eetimation of Cadmium as Oxide, By PHILIP E. BROWNING and LOUIS C. JONES (Amerr-. J. &Ski. [a], 2, 269-270, and Zed.anorg. Chem , 1896, 13, 110--112).-Muspratt has stated that the estimation of cadmiux as oxide by igniting the carbonate gives results which are much below the t r u t h ; no better results are obtained by dissolving the carbonate in nitric acid and igniting the nitrate. The authors state that when using the Gooch asbestos filter and crucible, the car- bonate may be converted into oxide without loss. Twenty-one experi- ments are quoted to show the trustworthiness of the process. E. C. R. L. DE K. Estimation of Lead in Potable Waters. By UBALDO ANTONY and T. BENELLI (Gaxxetta, 1896,26, ii, 194--195).-Potable waters may contain various substances, such as silicic acid, ferric, and aluminium hydroxides, in the colloidal state and, on adding the amount of ammo- nium chloride necessary for the complete precipitation of the lead and mercuric sulphides in accordance with the authors' method (Abstr., 1896, ii, 549) of estimating lead in water, these hydroxides would assume the insoluble form.It is recommended that after the lead sulphate has been weighed, it should be dissolved in hot ammonium tartrate solution, and any insoluble residue weighed and allowed for. W. J. P. Electrolytic Estimation of Mercury. By EDGAR F. SMITH and DANIEL L. WALLACE (J. Amer. C'iem. Soc., 1896, 18, 169-170).-The amount of mercury in cinnabar may be conveniently estimated by dis- solving about 0.22 gram of the mineral in 25 c . ~ . of solution of sodium sulphide (sp. gr. 1.2). After diluting to 125 c.c., the liquid is electrolysed in a platinum crucible at a temperature of 70" with a cur- rent of N.D. 100 = 0.12 ampitre.The precipitakion of the metal is New Method of Separating the Phosphates in the Ammonia Group. By N. TARUGI (Gaxxetta, 1896, 26, ii, 256-258).-The methods in general use for separating the precipitate of metallic phos- phates obtained with ammonia and ammonium chloride in qualitative analysis being inconvenient, the author has devised the following process, which gives excellent results. The precipitate is treated with cold acctic acid, when only ferric and aluminium phosphates and many of the oxalates remain undissolved ; after filtration, all the phosphoric acid and part of the oxalic acid is removed from the filtrate by adding excess of lead acetate. The lead salt is filtered off and the filtrate freed from lead by adding hydro- chloric acid and then hydrogen sulphide or thioacetic acid; after boiling off the hydrogen sulphide and filtering, the filtrate is poured complete within 3 hours.L. DE K.76 ABSTRACTS O F CHEMICAL PAPERS. drop by drop into a boiling concentrated sodium carbonate solution into which the precipitate not dissolved during the first treatment with acetic acid has been put. The only phosphate the precipitate can con- tain is ferric phosphate, which, however, gives no trouble in the subse- quent examination of the liquid for the metals. If the original precipitate contains no oxalates, the part insoluble in acetic acid can only contain ferric and aluminium phosphates and need only be examined for these two metals; the acetic acid solution is then treated with ammonia and ammonium chloride and examined in the ordinary way.W. J. P. Iodometric Estimation of Molybdic Acid. By FRANK A. GOOCH AND CHARLOTTE FAIRBANKS (Amer. J . Xci., 1896 [Q], 2, 156- 162).-Mauro and Danesi recommend heating the molybdate compound with hydrochloric acid and potassium iodide in a sealed tube filled with carbonic anhydride. The liberated iodine is afterwards titrated. Friedheim and Euler prefer submitting the mixture to distillation and titrating the iodine in the distillate. The authors have found that the molybdic acid is best estimated by acting on the residue with iodine in the presence of an alkali. A quantity of molybdic acid, in the form of an alkali salt, not exceeding 0.3 gram is mixed up with 20 C.C.of water, 20 C.C. of hydrochloric acid (sp. gr. 1.20) and 0.5 gram of potassium iodide, and after introducing the liquid into a narrow flaskit is rapidly boiled down to 25 C.C. but not further. The residue, after adding 1 gram of tartaric acid, is nearly neutralised with aqueous soda, and then mixed with a slight excess of sodium hydrogen carbonate. A definite quantity of iodine solution is now at once added, and the corked bottle is set aside for 2 hours. The excess of iodine is titrated by means of arsenious oxide. One atom of iodine corresponds with 1 mol. of molybdic acid. L. DE K, Application of the Blue Oxide of Molybdenum in Volumetric Analysis. By ATTILIO PURGOTTI (G'ccxxettcc, 1896, ii, 197--220).-The blue oxide of molybdenum, Mo308, is readily oxidised by such sub- stances as permanganates, chromates, hypochlorites, chlorine, peroxides, ferric salts, and platinic and auric chlorides, and since the oxidation of the whole of the oxide is rendered evident by the disappearance of the characteristic blue colour, it may be used for the volumetric estimation of oxidising agents.The reduction of molybdic anhydride occurs in two stages in accordance with the equations 5Mo0, + 16H = Mo507 + 8H,O and Mo,07 + 19Mo0, = 8M0308, so that if a solution containing 5Mo0, be completely reduced to the brown oxide, Mo507, and then added to a solution containing 19Mo03, this will contain only the blue oxide. The standard solution of the blue oxide is made by reducing 1-1 gram of ammonium molybdate, (NH,),Mo70,,,. 4H,O, dissolved in 30 C.C.of water and 5 C.C. of pure sulphuric acid with 4-5 grams of zinc dust; after filtering the brown solution, it is made up to 200 C.C. and added to a solution of 4.2 grams of ammonium molybdate and 2 C.C. of pure sulphuric acid in 800 C.C. of water. The solution is then boiled until blue, and on cooling is ready for use; it is approximately N/50, and cannot be made N/lO because of theANALYTICAL CHENISTRY, 77 sparing solubility of the oxide. The standardising is performed by diluting 10 C.C. of N/100 potassium dichromate to 30 c.c., adding 3 C.C. of 1 : 3 puresulphuric acid, and running themolybdenum solution into the hot solution until a persistent blue colour is observed ; the solution does not change in strength if preserved in well-closed full vessels.For the indirect estimation of substances such as cupric salts which are not reduced by blue molybdenum oxide, the author does not use standard ferrous sulphate solution but prefers t o reduce them with alkaline chromium hydroxide solution and subsequently estimates the chromate formed by titration with molybdenum solution. 10 c.c, of 16 per cent. chrome alum solution is mixed with 30 C.C. of 30per cent.. caustic potash giving an alkaline solution of about 0.32 gram of chro- mium hydroxide; this is boiled for about 15 minutes with 10 C.C. of a cupric salt containing about 0.15 gram of copper. The excess of chromium hydroxide is thus rendered insoluble, and potassium chromate remains in solution; the latter is then estimated by filtering the solution, making up to a standard volume and titrating an aliquot part with molybdenum solution after acidification with sulphuric acid.The titration of hot permangamate or hot dilute ferric solutions with molybdenum solution gives excellent results. Good results are obtained in the estimation of lead by precipitating it as chromate and filtering, washing and dissolving the precipitate in caustic potash ; the solution is then acidified with sulphuric acid and titrated with molybdenum solution. Lead solutions may also be boiled with calcium hypochlorite in feebly acid solutions and the precipitated lead peroxide filtered, washed and boiled with the alkaline chromium hydroxide as described above. After separating the insoluble chromium hydroxide, the filtrate is acidified with sulphuric acid and titrated with molybdenum solution.Silver chloride or sulphate may be estimated by boiling with alkaline chromium hydroxide, when metallic silver is formed ; the chromate produced is then estimated with molybdenum solution. The results obtained with silver nitrate solution are rather too high owing to the slight action of the nitric acid on the molybdenum solution. Both mercuric and mercurous salts are reduced to metallic mercury by alkaline chromium hydroxide solution, and may be estimated indirectly by titrating the chromate with molybdenum solution. Nickel and cobalt salts are converted into the sesquioxides by heating with calcium hypochlorite or sodium hypobromite solution and may then be estimated in the same way as lead peroxide.Good test results were obtained with all the methods described above; the presence of nitric acid is, however, to be avoided in titration with molybdenum solution. W. J. P. Reactions of Tungsten. By E. DEFACQZ (Conzpt. Tend., 1896,123, 308-310).-When a tungsten compound is converted into tungstic acid, heated with four or five times its weight of potassium hydrogen sulphate and a few drops of sulphuric acid, and then mixed with sufficient concentrated sulphuric acid to prevent solidification on cooling, the liquid obtained gives colour-reactions with a large number78 ABSTRACTS OF CHEMICAL PAPERS. of organic compounds. The best results are obtained with phenols and alkaloids, and the most important of these reactions are as follows :-pheiaoZ, very intense deep red ; puinol, very intense amethyst-violet ; ccctechol, violet black ; a- or P-naphthol, violet-blue ; sccZicyZic acid, very intense deep red ; vemt&e, intense sienna colour.Many of the alkaloids give no coloration, and of the various compounds used phenol and quinol are the most valuable for analytical purposes, the reaction with them being much more sensitive than the well-known production of a blue coloration by the action of zinc or some similar metal. As a rule, the colorations disappear on adding water. C. H. B. Reduction of Vanadic Acid by Hydriodic and Hydrobromic Acids, and its Titration in Alkaline Solution with Iodine By PHILIP E. BROWNING (Amer. J. Xci., [4], 2,185-188,and 2eits.anorg. Clhern , 1896, 13, 11 3-1 16).-The solution containing the vana- date is boiled in an Erlenmeyer beaker with potassium iodide or bromide and a regulated amount of sulphuric acid, until no more iodine or bromine is liberated.After cooling, the residual liquid is nearly neutralised with aqueous potash, a small quantity of tartaric acid is added, and the neutralisation completed with an excess of potassium hydrogen carbonate. Excess of standard iodine is then added, and after remaining for half an hour in a closed bottle, the free iodine left is estimated by means of a solution of arsenious oxide. One mol. of iodine represents 1 mol. of vaaadic acid. L. DE K. Estimation of Bismuth. By WJLHELM MUTHMANN AND F. MAWROW (Zeits. ccnorg. Chem., 1896, 13, 209--210).-The faintly acid solution of the bismuth salt is treated with an excess of hypophosphorous acid, and warmed on the water bath until the supernatant liquid is clear and a further addition of hot hypophosphorous acid does not cause any coloration.The reddish- grey precipitate of metal thus obtained is easily collected; after being washed with hot water, and with absolute alcohol, it is dried at 105", and weighed either on a tared filtered paper or in a Gooch's crucible. The results are very accurate. The method is especially useful for the separation of bismuth from those metals which are not precipitated by hypophosphorous acid, such as zinc and cadmium. E. C. R. Platinum Amalgam and its Application in Analysis. By N. TARUGI (Gcmxetta, 1896, 26, i, 425-43 1 ).-Magnesium precipitates the whole of the mercury and platinum, from a solution containing both mercuric and platinic chlorides, as a black precipitate in which, even when it contains only 1 per cent.of platinum, no metallic mercury can be detected under the microscope. Further, the precipitate is always readily soluble in concentrated nitric acid, even if it only contains 1 per cent. of mercury, but if precipitated mercury and platinum be mixed, nitric acid dissolves mercury alone from the mixture; the solubility of the amalgam is therefore not due to the retention of chlorine by the precipitated metals.ANALYTICAL CHEMISTRY. 70 The author proposes to apply these facts to the qualitative analysis of solutions which may contain gold, mercury, and platinum. The gold is first precipitated by oxalic acid, and, after separating it, magnesium is added to the filtrate; a grey precipitate can only be mercury, a black precipitate insoluble in nitric acid is platinum, whilst a black precipitate soluble in nitric acid shows that both platinum and mercury are present. W.J. P. Separation of Palladium from Platinum. By PAUL COEN and FRANZ FLEISSNER (Monatsh., 1896, 17, 361--364).-The solution of the two metals in aqua regia is repeatedly evaporated with water in order to eliminate nitric acid, and again with about 10 C.C. of a 10 per cent. solution of ammonium chloride. The residue is then warmed with a fewdrops of water,and covered with a 30 per cent. solution of ammonium chloride, when ammonium platinochloride is gradually precipitated, this is separated by filtration, and washed, first with a solution of ammonium chloride and then with alcohol, and is finally transferred to a platinum crucible and heated to redness.The palladium chloride present in the filtrate is mixed with fairly strong nitric acid, and the whole evaporated on the water bath, when a beautifully crystalline red precipitate is formed ; this is collected, and mashed with a strong solu- tion of ammonium chloride to which a few drops of nitric acid have been added. The precipitate consists of cmmonizcin pcdZacliochZoride, Pd(NH,),C16 ; if insufficient nitric acid has been used, a brown basic salt is obtained instead. The red ammonium palladiochloride is sparingly soluble in cold water, and is decomposed by warm water, with production of ammonium palladious chloride, (NH,),PdCl, ; even in the cold so- lution, a slow decomposition takes place.It may be used for the estimation of palladium, being decomposed when heated in an atmo- sphere of coal-gas, leaving a residue of palladium. A series of ex- periments have served to show that, by observing the above conditions, the amounts of platinum and palladium in a mixture of their chlorides may be accurately estimated. A. L. Technical Analysis of Asphaltum. By LAURA A. LINTON (J. Amel-. Chem. Xoc.. 1896, 18, 275--279).-The author gives a few more instructions as to the assay of asphaltum (Abstr., 1895, ii, 333). I n estimating the moisture, the temperature should not exceed 50°, and the drying is best effected by heating the sample in a current of dry air ; the dried sample is then tested as directed.It is now recommended to fraction the asphaltene by estimating the portion soluble in boiling turpentine and that soluble in chloroform only. After removing the petrolene, the residue on the filter is digested in boiling turpentine until the filtrate is colourless ; the filter is then washed with alcohol and dried at 100". If a black semi-liquid substance separates from the mass, the extraction with turpentine should be repeated ; the residue on the filter is finally exhausted with chloroform to remove the portion undissolved by the turpentine. Aged " varieties of asphaltum contain a larger proportion of asphal-80 ABSTRACTS OF CHEMICAL PAPERS. tene, but the fraction soluble in turpentine is smaller, whilst that soluble in chloroform is larger. L. DE K.Estimation of Glucose in Urine. By B. A. VAN KETEL (Zeit. p 7 y S i O l . Chenz., 1896, 22, 278- 280)-The method originally used in the estimation of sugar in milk may also be used for the estimation of sugar in urine which is also rich in uric acid, or contains proteid or blood, To 50 C.C. of the liquid, 4 C.C. of liquid phenol and 10 C.C. of a 10 per cent. aqueous solution of lead acetate are added, and the mixture shaken and filtered. The filtrate, to which are added the washings of the filter, the whole being brought up to 100 c.c., can then be examined for sugar by the polarimeter, or after removal of the lead, and dilution, by means of Fehling’s solution. Osazone crystals can also be prepared. W. D. H. Estimation of Sugar in Blood. By FREDERICK W. PAVY (Proc.&iysioZ. Xoc., 1896, 7--lO.)-The importance of the estimation of sugar in blood correctly is obvious. The difficulties of the analysis are great, because the proteids present must first be got rid of by pre- cipitation in a form that lends itself to thorough washing. The author’s alcohol method still holds; but the last traces of proteid in the alcoholic extract are best got rid of by boiling with hydrated a1 umina. W. D. H. Polarimetric Estimation of Milk Sugar in Human Milk. By PAUL THIBAULT (J. Phcwm., 1896 161, 4, 5--10.)-In the analysis of cows’ milk, acetates of lead or mercury, or sodium metaphosphate may be used t o precipitate the proteids and fat. I n dealing with human milk, however, these reagents do not give a liquid clear enough for optical examination.The author finds that a solut,ion, containing, in 1 litre, 10 grams of picric acid and 25 C.C. of glacial acetic acid, when added to an equal volume of human milk gives, after filtration, a perfectly clear liquid, in which the milk sugar can be easily esti- mated by the optical method. A method is also given for the deter- mination of the volume occupied by the fats, &c., previously separated. (Compare Wiley and Ewell, Abstr., 1896, ii, 628.) M. W. T. Gravimetric Estimation of Sugars, especially of Maltose, by means of Fehling’s Solution. By HARTOG ELION (Rec. (rruv. C‘him., 1896, 15, 116--122).-1n the estimation of sugars by Fehling’s solution, it is always advisable to oxidise the cuprous oxide to cupric before reducing it in a current of hydrogen.(Compare Abstr., 1891, 368.) Another error in the estimation is caused by the action of the alkali on the asbestos filter ; this error may be eliminated to a large extent by taking the mean weight of the filter before and after the experi- ment. A third error, due to a secondary decomposition of the Fehling solution, may be eliminated by making a blank experiment, using an equal quantity of water instead of the sugar solution.AXAIATTICAL CHEMISTRY. S l The author finds that in the case of maltose the Fehling’s solution is reduced at the end of 2 mins., so that longer boiling is unnecessary. J. J. S. Rapid Process for the Detection of Formaldehyde in Milk. By GEORGES DENIGBS (J. Pluc~m., 1896, [6], 4, 193--195).-Ten C.C. of milk is diluted with water and, after the addition of two or three drops of acetic acid and some potassio-mercuric iodide, the solution is filtered.One C.C. of Schiif’s reagent (magenta decolorised by sulphurous acid) is then added, and, after 10 mins., 2 C.C. of hydrochloric acid. The amount of formaldehyde present is indicated by the depth of the violet colour produced. M. W. T. Estimation of Hydrocyanic Acid in Officinal Waters. By CARL GLUCKSNANE (Chem. Cent?.., 1896, i, 329 ; from P?mm. Post., 28, 569-57O).-The author has not succeeded in getting trustworthy results by Mohr’s copper sulphate process, the end reaction being very uncertain. Other investigators also condemn the method. L. DE I<. Palmarosa Oil. By EDUARD GILDEMEISTER and KARL STEPHAN (Arch. Phcc1-9r~, 1896, 234, 321-330).-See this vol., i, 81, Estimation of the Constituents of a Mixture of Primary, Secondary and Tertiary Aniines of the same Radicle.By CHARLES GASSMANN (Compt. rend., 1896,123,313-315).-l’he method described was worked out with special reference to the ethylenediamines. The dried mixture is dissolved in a definite quantity of water, and an aliquot part is titrated with normal hydrochloric acid, using phenol- phthale’in as indicator. An equal volume is then mixed with one and a half times the volume of normal hydrochloric acid indicated by the first experiment, diluted with twice its volume of alcohol, cooled with ice, and titrated with normal sodium nitrite solution, using starch paste and potassium iodide as indicator. If Mx, My, and Mz are the respective molecular weights of the mono-, di- and tri-amines, A the weight of the mixture taken, B the number of C.C.of normal acid, and C the number of C.C. of normal nitrite solution required by A, then x, y, and z, the respective quanti- ties of the mono-, di-, and tri-amines present in A are given by the equations. x = [(My - T\IIz)C) + (BMz - 1000A)]IT~ - __ ~ _ _ 1000(Nly - Mx) 1000(My - hlx) /J = [1000A - BMz + C(MZ - Mx)]My x = (B - C)Mz. 1000 For the ethylenediamines Mx = 59-56, My = 85-90 and X z = 111.84 VOL. LXXII. ii. G and the equations become82 ABSTRACTS OF CHEMlCAL PAPERS. x = 0.13706B - (2.272168 + 0.02947C) x = 0*05592(B - C). = 3.31148. - 0.18517B + 0.0859C The results are accurate to 0.33 to 0.5 per cent. Qualitative Examination of Acetanilide. By CHARLES PLATT (J.Amer. Chem. Soc., 1896, 18, 142--146).-The following teats are recommended : strong cold nitric acid gives a colomless solution which on gentle heating turns first yellow and then brownish-red, evolving oxides of nitrogen. The cold solution also gradually assumes a brown colour, and deposits red, acicular crystals having an odour of nitro- benzene. If the nitric acid solution is rapidly evaporated to dryness, an oily residue of decided odour is left, but on slow evaporation a crystalline residue of slight odour is obtained. Dilute nitric acid dissolves the acetanilide in the cold with separation of oily globules ; and this solution, on slow evaporation, gives a brown residue with slight purplish tint. When boiled with the dilute acid, a colourless solution is obtained, and pungent fumes are evolved.Strong sulphuric acid dissolves the compound yielding a colourless liquid which is not affected by boiling. The cold solution gradually acquires a pink nr even brown colour, gradually changing t o orange when viewed by reflected light ; subsequently, t u f t s of delicate acicular crystals appear, and the liquid becomes colourless. Sulphuric acid and potassium dichromate give a dark green solution. I f the solution of the compound in strong sulphuric acid is diluted before adding the chromate, no reaction is at first obtained, but gradually a reddish-brown colour is developed, changing to a dark olive-green. Hydrochloric acid, alone or in conjunction with potassium dichro- mate, gives no marked reaction, but if the compound is dissolved in hydrochloric acid and then mixed with a weak solution of chromic acid a dark green coloration is finally observed.Aqueous potash produces a blue precipitate in this solution. Bromine water added to the hydrochloric acid solution yields a heavy yellowish precipitate of bromaniline ; chlorine water, or a solu- tion of bleaching powder, yields, however, no precipitate but gives a dark blue coloration which soon fades. If, before adding the bleaching powder, a few C.C. of a saturated solution of phenol is added, a brownish red colour is produced which turns blue on adding ammonia. Aqueous potash liberates aniline, and if chloroform is also added, the mixture on heating gives the characteristic isonitrile reaction. Sulphuric acid and sodium nitrite produce a fine red colouration.Ferric chloride gives no reaction. Zinc chloride at a temperature of 270" causes the formation of a small quantity of flavaniline, a yellow substance with a green fluorescence. After acetanilide has been boiled with dilute nitric acid and potassium nitrite, the liquid turns deep red on boiling it with Plugge's reagent (a solution oE mercurous nitrate containing nitrous acid). By means of these tests, acetanilide may be distinguished from sntipyrine and phenacetine. Antypyrine also diff ers from acetanilide in being precipitated by mercuric chloride. C. H. B. L. DEK.ANALYTICAL CHEMISTRY. 83 Estima€ion of Caffeine. By MOSES GOMBERG (J. Amer. Chem. (soc., 1896, 18, 331-342).-See this vol., i, 129. Estimation of Caffeine.By GEORGES (J. Phccrm., 1896 [6], 4, 58-59).-0*5 gram of the finely powdered sample is mixed with fine sand, and thoroughly extracted with a 1 per cent. solution of sodium salicylate. The liquid is evaporated to about 50 c.c., and then shaken with chloroform; on evaporating the chloroform, the caffeine is left in a state of purity. Estimation of Caffeine in Tea. By MARIUS L. Q. VAN LEDDEN HULSEBOSCH (Chem. Centr., 1896, i, 332; from Phu~m. Centr., 36, 742).-Five grams of dry powdered tea is mixed with 1 pram of calcium hydroxide and heated with 100 C.C. of water on the water bath for 3 hours. After restoring the loss caused by the evaporation, the liquid is filtered arid 50 C.C. of it ismixed with 0.5 gram of sodium carbonate. After filtering and evaporating the liquid to about 15 c.c., it is introduced into an extractor and submitted to the action of ether for 3 hours ; the ethereal solution on evaporation leaves pure caffeine.The author thinks the process may be applied to coffee, cocoa and kola. By MELCHOIR KUBLI (Chem. Centr., 1896, i, 324-225 ; from Pl~urm. Zed. RUSS., 34).--Thc author (compare Abstr., 1896, ii, 550) proposes another test for the purity of quinine sulphate, based on the following interesting reaction. When a neutral solution of quinine sulphate is precipitated by means of sodium carbonate, the liquid becomes clear again on adding solution of sodium hydrogen carbonate ; but on passing a current of carbonic anhydride, the quinine is precipitated as normal carbonate, the volume of which may be measured in a graduated tube.The presence of the salts of other cinchona alkaloids (hydroquinine excepted) exercises a remarkable influence on the volume of the pre- cipitate, also on its appearance. M. W. T. L. DE K. Testing Quinine. Several examples are given. L. DE I(. Estimation of Quinine Salts by Means of Sodium Nitro- prusside. By I. G. KRAMERS (Rec. Fmv. Chirn., 1896, 15, 138-147).- On the addition of a solution of sodium nitroprusside to a solution of :I neutral salt of quinine, small tarry drops separate, which collect on the sides and bottom of the vessel, and then gradually change to salmon-coloured needles. A dilute solution of quinine (1 in loo), when heated to 80" and then treated with the nitroprusside, yields no permanent precipitate at first, but on keeping at the same temperature for some time the salmon-coloured needles separate, and on cooling more crvstals are formed. but no tarrv matter.These needles have the corniosition (C20H24~202)4, Fe,(Cg),,(NO),H? + H,O. They are insolubIe in ether and benzene, sparingly soluble In cold alcohol, more readily in hot,. They melt and hecomiose a t 177-185", and at the same time become blue. The moist crystals also turn blue when exposed t o bright sunlight or when heated above 105", and they are only slightly hygroscopic.84 ABSTRACTS OF CHEXICAL PAPERS. The only other alkaloid which gives a similar sparingly soluble compound with sodium nitroprusside is hydroquinine. 1-07 milligram of cinchonidine, 1-62 of quinidine, 2.68 of cinchonine, and 5.74 of homocinchonidine in 1 C.C.solution yield no crystalline precipitates. The method can therefore be made use of for testing the purity of quinine salts. The quinine is precipitated by means of the nitroprusside, and a few drops of ammonia are added to the filtrate, when, if the salt is pure, no precipitate will be formed. Estimation of the Alkaloids in Nux Vomica. By C. C. KELLEH. (Chem. Cent?.., 1896, i, 228 ; from Schweitx. TF'och. Cliem. Phmn., 33, 452).-Twelve grams of the powdered beans is introduced into a 200 C.C. flask and 80 grams of ether and 40 grams of chloroform are added; after half an hour 10 C.C. of 10 per cent. ammonia is added, and the whole is shaken at intervals for half an hour. After adding 15-20 C.C. of water and thoroughly shaking, 100 C.C. of the ethereal mixture is poured off into a separating funnel and shaken with 50 C.C. of 0-5 per cent. hydrochloric acid: the shaking being repeated with another 25 C.C. The acid liquid is drawn off, and after adding excess of ammonia, it is agitated thrice with 30 C.C. of chloroform mixed with 10 C.C. of ether. This, on evaporation, yields the alkaloids from 10 grams of J. J. S. the beans. L. DE K. Separation of the Proteids of Milk. By A. SCIILOSSJIANN (Zeit. By GEORGES (J. Ph*rn., 1896 [GI, 4, 108--110).-Mercier (J. Pfinrnz., [6], 515) bas shown that in order to obtain accurate results the urine should be diluted with water, so that the quantity taken for analysis does not contain more than 0.1 gram of albumin, When much water has been added, the albumin shows a tendency to redissolve; this the author proves experimentally to be due to the dilution of the salts present in the urine. H e suggests a method of analysis in which a saturated solution of magnesium sulphate is used as a precipitant. New Process for Estimating Albumin in Urine. By E. RIEGLER (Chem. Centr,, 1895, i., 332; from Ken. Ned. BZ., 1895, 761).-Ten grams of asaprol is dissolved in 100 C.C. of water, and 10 C.C. of hydrochloric acid and 5 C.C. of this solution are added to 50 c.c of urine, and the whole heated to 60". The precipitate is collected, washed with about 150 C.C. of water, pressed dry between filter-paper, and finally dissolved in 25 C.C. of N/10 potash. The difference in the refractive index of this solution and that of the potash by itself serves as a measure for the estimation of the albumin. Divided by 540, the amount of albumin in 50 C.C. of urine is obtained. I f the wine is rich in albumin, a smaller quantity must be taken; if poor, a larger physiol. Chem., 1896, 22, 197-226).-See tlils vol., ii, 62. Estimation of Albumin in Urine. IT. W. T. amount. (Compare Abstr., 1895, ii, 542.) L. DE K.