386 ABSTRACTS OF CHEMICAL PAPERS INORGANIC ANALYSIS. Aeration Method for Ammonia. B. S. Davisson, E. R. Allen, and B. M. Stuttlefield. ( J . I n d . and Eng. Chem., 1916, 8, 896-899.)-The authors have in- vestigated the conditions under which ammonia can be quantitatively distilled in a current of cold air, with minimum risk of decomposing nitrogenous organic matter and with complete absorption of the ammonia in standard acid.Magnesia is prefer- able t o stronger alkalis for liberating the ammonia, as it has less effect on organic matter and is less liable to be carried forward mechanically into the standard acid by strong air currents. Magnesia, of which 0.6 grm. is usually sufficient, works admirably, but rapid air cur- rents are requisite when using it, if the determination is to be complete in two and a half hours.For these rapid air currents (about 1,000 iitres an hour), Folin tubes are useless, and the apparatus illustrated is used by the authors. The main part of the absorption tube is 14 inches in diameter and 15 inches long. The side arm has a bore of 8 rnm. C and E are glass rods, about 1+ inches long, held in place by baffles made from rubber gasket.The purpose of the baffle at E is to stop any acid which spatters from the lower part of the tower. The aeration bulb D is well perforated, so tha.t complete stirring of the solution will be obtained, and should extend well to the bottom of the flask. The tubes connecting the flask t o the absorption apparatus an one side as shown, and to the next unit in the series, which may conveniently be as many as ten sets, are of 5 mm.bore. The entering air should be scrubbed successively with sodium hydroxide and 25 per cent. sulphuric acid. If the scrubbing with sodium hydroxide be omitted, the part set in the series may yield low results, owing to the small quantity of magnesia, used becoming largely carbonated, and it is desirable not to use large (10 grin.) quantities, as is sometimes done.NOTE BY EDIToR.-The use of magnesia is undesirable in ammonia distillations in presence of phosphates, as some ammonia may be retained as ammonium magnesium phosphate. G. C. J. Volumetric Estimation of Cobalt. W. D. Engle and R. G. Gustavson. (J. Ind. and Eng. Chem., 1916, 8, 901-902.)-The method depends on the fact that sodium perborate, in presence of alkali hydroxide, oxidises cobalt to cobaltic hydroxide, butIXORGANIC AKALYBIS 587 does not oxidise nickel.The excess of the reagent is readily decomposed by boiling and the cobalt can then be estimated iodometrically. The ore or other material is dis- solved by means of acids, and the metals of the copper and iron groups, and also manganese, are removed by standard methods.The solution so obtained may contain cobalt, nickel, and zinc, but must be free from substances capable of liberating iodins from an acid solution of potassium iodide. The solution (100 c.c.) is acidi- fied with dilute sulphuric acid, of which an excess of about 5 c . ~ . is added. Sodium perborate (1 to 2 grms.) is added, and, after it has dissolved, sodium hydroxide is added to strong alkaline reaction and the mixture boiled for ten miqutes t o decom- pose the excess of perborate.When cool, 1 grm. potassium iodide is added, the solution acidified with dilute sulphuric acid, and, after solution of the precipitate, the liberated iodine is titrated against standard thiosulphate. The latter may be standardised against pure, anhydrous cobalt snlphate, treated as described, or more conveniently against potassium bichromate, K2Cr,0, = 6 Co.The extreme error of the method, even in presence of ten times as much nickel as cobalt, appears to be no more than corresponds to 0.1 C.C. of the standard thiosnlphate used. G. C. J. Use of Solutions of Borax and Boric Acid in the Colorimetric Estimation of the Concentration of Hydrogen Ions in Sea-Water.S. Palitzsch. (Compt. Rend. Trav. Lab. Carlsberg, 1916,11, 199-211 .)-In Soerensen and Palitzsch's method fgr the estimation of the concentration of hydrogen ions in sea-water by colori- metric comparison with standard solutions with the addition of suitable indicators (phenolphthalein, naphtholphthalein, methyl red), the standard solutions of sodium borate and hydrochloric acid indicated (see AXALYST, 1910,35,216 ; 1913,38,394) give satisfactory results.In the case of a Polar expedition, however, practical difficulties arose which made it desirable to prepare the standards beforehand in the form of accurately weighed quantities of solid ingredients which could be dissolved in dis- tilled water when required for use.The author has therefore worked out a com- bination of borax and boric acid, the utility of which is not confined to the special purpose for which it was designed, and which shows many adva'ntages over the older standards for general use. Borax specially purified for analysis and suitable for the purpose is readily obtain- able; its purity should be checked by titration of the base with & hydrochloric acid in presence of methyl red, which gives a much sharper end-point than methyl orange.The moisture is determined by heating carefully but fairly strongly to redness in a platinum crucible. The boric acid is titrated in presence of glycerol and a moderately large quantity of phenolphthalein, using for comparison a blank solution of glycerol; results sufficiently accurate are obtained with 75 C.C.of gly- cerol for 0*5grm. of borax, although 150 C.C. are required for very high degrees of accuracy. If carbonates are present the carbonic acid must' first be expelled by boiling with sulphuric acid under a reflux condenser for five minutes. The con- centrations of the solutions most suitable for estimations in sea-water are: ,& of borax, equivalent to To sodium hydroxide-Le., 19*108 grms.per litre-and :' of boric acid-Le., 12.404 grins. per litre-to which are added 2.925 grms. of sodium388 ABSTRACTS OF CHEMICAL PAPERS chloride to compensate the '-salt error," the error due to the iiiodification of the eolour of the indicator by the salts apart from their influence on the ionic conceii- trittion. The author has staiidardised mixtures of borax and boric acid solutions by the electrical method, obtaining values set forth in the table below: CONCENTRATIONS OF HYDROGEN IONS IN MIXTURES OF BORAX AKD BORIC ACID.Borax TT. C.C. 10.0 9.0 8.0 7.0 6.0 5.5 5.0 4.5 4* 0 3.5 3.0 2.5 2.3 2.0 1.5 1.0 0.6 0.3 Boric Acid y. P&. 9.24 9.11 8.98 8.84 8.69 8-60 8.51 8.41 8.31 8.20 8.08 7.94 7.88 7.78 7.60 7.36 7.09 6-77 CA x109.0.58 0.78 1.05 1.45 2.04 2-51 3.09 -3.89 4.90 6.31 8.32 11.5 13.2 16.6 25.1 43.7 64.6 170 The errors due to the salts in sea-water have not been re-determined in the case of the borate solutions now proposed, but the corrections to be applied are the same as were prescribed for the older standards (ANALYST, Zoc. c i t . ) . J. F. B. Loss of Phosphoric Acid during Fusion with Ammonium Fluoride.W. A. Davis and J. A. Prescott. ( J . Agric. Sci., 1916, 8, 136-138.)-1n the analysis of salts or minerals containing phosphoric acid, treatment with hydrofluoric acid or ammonium fluoride was found to result in a considerable loss of phosphoric acid, which appears to be volatilised as phosphorus fluoride. The loss is least with phos- phates of the alkali metals, while the loss from phosphates of the alkaline earths is considerably greater and may rise to over 50 per cent.in the case of minerals such as apatite. The loss from disodium hydrogen phosphat,e is less than that from potassium dih-ydrogen phosphate. Experiments showed that the loss which occurs during ignition with sulphuric acid only takes place when there has been previous treatment with ammonium fluoride.H. F. E. H.INORGANIC ANALYSIS 389 Estimation of Moisture in Resinous Woods. E. Azzarello, (Annali Chirn. Applic., 1916, 6, 154-15$.)-From 1 to 3 grins. of fine shavings of t,he wood are weighed in the tared flaskd provided with a stopper I. The stopper is then replaced by the tube B-B, which has previously been charged with fragments of calciuin oxide placed in alternate layers with tufts of glass wool and then weighed.To the end of the small tube P is attached the tube C, filled with calcium chloride, to prevent the lime in B absorb- ing moisture from the air. The stopper E is turned so as to put B in communica- tion with A , the tap H is opened, and the apparatus is placed in an oven main- tained at 125' to 130" C.After thirty minutes it is allowed to cool with the tap H closed, and then replaced in the oven with the tap - open, this process being repeated until water is no longer condensed on the walls of the connection between A and B. The flask A may then be detached and weighed from time to time until the weight diminishes less than 2 to 3 mgrms. The loss gives the amount of volatile oil and water.The tube B-B is then heated wiOh the tap open in an oven at 200" C. until the weight becomes constant within 2 to 3 mgrms. This gives the moisture absorbed by the lime. Experiments with mixtures of water, volatile oil, and dry mineral matter show that the results are invariably too high, but are accurate within 0.5 per cent. C. A. M. Detection of Small Quantities of Selenium and its Distinction from Arsenic.J. Meunier. (Comptes rend., 1916, 165, 332-334.)-Selenious acid and selenites, when reduced with zinc and sulphuric acid, yield hydrogen selenide, a gas which is readily decomposed by heat with the deposition of selenium. The deposit of selenium obtained in a Marsh tube, however, has a red colour, particularly a t its densest part, and is quite unlike the deposit yielded by arsenic under similar con- ditions. When oxidised, the deposit is converted into white selenious acid. Larger quantities of selenious acid may be distinguished from arsenic by t'reating their hot solution with hydrogen sulphide; a turbidity due to precipitated sulphur is obtained, and, by heating the mixture for some time on a water-bath, this sulphur settles and390 ABSTRACTS OF CHEMICAL PAPERS entrains the selenium and arsenic sulphides which are formed. If seleiziurn sul- phide is present, the precipitated sulphur has a brown appearance, whilst the yellow colour of the sulphur is not altered by the presence of arsenic sulphide. If the pre- cipitate is collected, dried, and cautiously heated in a tube, t'he free sulphur vola- filises and a black residue of selenium sulphide remains. w. P. s.