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the raw ground cinder, these proposals lose much of their interest. According to one of these patents (Munro and Wrightson, No. 250, A.D. 1885), ground basic cinder is used as a precipitating agent for the soluble phosphoric acid of rich superphosphate, and by mixing the two substances in suitable proportions, a manure of moderate richness is obtained, free from any excessive proportion of oxides of iron, and containing phosphoric acid in three highly assimilable forms,―soluble, "precipitated," and cinder phosphoric acid. The plots on which this manure was tried show that the efficacy of the soluble phosphoric acid was not weakened by partial precipitation, and that the cinder phosphoric acid in the compound manure exercised a manurial effect over and above that due to the phosphoric acid of the superphosphate. The manufacture of a superphosphate from basic cinder itself has also been tried and patented (Munro, No. 7740, A.D. 1885). When treated with the proper quantity of sulphuric acid, basic cinder is converted into a light green, dry, friable, and very open substance containing a large proportion of calcium sulphate, soluble phosphate of lime, and about 12 per cent. of crystallised ferrous sulphate. (A portion of the phosphoric acid exists as soluble ferrous phosphate.) In view of the recent experiments of Griffiths, it was thought that the ferrous sulphate contained in this manure might exert a beneficial effect on vegetation, instead of being, according to the common belief, an absolute poison. The effect of ferrous sulphate on vegetation seems to depend on the dose, a small quantity being sometimes beneficial, and a large one invariably noxious. On the experimental plots to which the "dissolved cinder" was applied, the effect of the ferrous sulphate appeared to be uniformly disadvantageous. The dissolved cinder in all cases had some manurial value, giving increases over the unmanured plots, but these increases were less than were obtained with the same quantity of cinder not dissolved by acid, so that the sulphate of iron appears to have neutralised a part of the benefit derived from the phosphoric acid. J. M. H. M.

Influence of the Ferrous Oxide in Basic Cinder on the Growth of Plants. By J. M. H. MUNRO (Middlesborough, 1886).-This report contains experiments supplementary to those which formed the subject of the preceding Abstract. Seeds of various sorts-barley, white turnips, clover, white mustard, garden cress-were sown in mixtures of garden soil with basic cinder, in order to ascertain whether the large proportion of ferrous oxide in the basic cinder exercises any unfavourable influence on germination or growth. In order to put this question to the severest test, enormously exaggerated doses of basic cinder were employed, namely, 10 per cent. of the mixed soil, 25 per cent., 50 per cent., and pure basic cinder without any soil. Mcst of the seeds tried germinated even in the pure basic cinder, and some of the plants lived until starved for want of nitrogenous food. All the other mixtures produced plants which flowered and seeded in due course the barley plants in the mixture of equal parts of basic cinder and garden soil were actually better than those grown in garden soil alone, and produced full ears of grain of unimpaired germinating power. Since basic cinder is an alkaline substance containing free

lime, it is only natural that in the three strongest mixtures fewer seeds germinated than in the three weaker mixtures or in garden soil alone. The conclusion arrived at is that the ferrous oxide contained in basic cinder is without injurious influence on germination or growth. J. M. H. M.

Analytical Chemistry.

Apparatus for Gas Analysis. By O. PETTERSSON (Zeit. anal. Chem., 25, 479-484). The principle on which the measurements are made is similar to that employed for air analysis (this vol., p. 180). The standard volume of air is, however, contained in a special bulb connected with the eudiometer through the differential manometer. The gas is introduced by a side tube from a bell-glass inverted in a mercury trough. The absorptions take place in Orsat tubes connected with the eudiometer by stopcocks. There are also wires for explosions. M. J. S.

Universal Spectroscope for Qualitative and Quantitative Chemical Analysis. By G. KRUSS (Ber., 19, 2739-2746).-A modified form of Bunsen and Kirchhoff's spectroscope is described with sketches.

New Volumetric Method for Determining Fluorine. By F. OETTEL (Zeit. anal. Chem., 25, 505-511).—The fluorine is measured as silicon fluoride in a special form of eudiometer. The decomposition vessel is a stoppered flask with the neck above the stopper enlarged into a cup for holding mercury. A tube branching from the neck is ground into the top of the eudiometer, the joint being also covered with mercury. The eudiometer is connected at its lower end with a mercury tube like that of the nitrometer. The graduation begins 10 c.c. below the top of the eudiometer, and 10 c.c. of sulphuric acid are introduced above the mercury. To obtain sulphuric acid suitable for the decomposition, ordinary acid is heated with sublimed sulphur until it begins to fume, then poured off from the fused. sulphur and evaporated to two-thirds of its volume. The fluoride (which if decomposable by cold acid may be enclosed in a tube sealed by a drop of fused acid potassium sulphate) is placed in the flask with ignited quartz-powder. After reading the mercury level and temperature, 50 c.c. of acid is added and the stopper inserted. The acid is slowly heated to boiling, whilst the pressure is kept below that of the atmosphere, to prevent leakage. When decomposition is complete, the whole is allowed to cool and the volume of the gas read off. A correction of 14 c.c. is added for the solubility of silicon fluoride in sulphuric acid. The results are equal in accuracy to those obtained by Fresenius' method, and the whole determination requires only three hours, of which two are occupied by the cooling. M. J. S.

Air Analysis on a New Principle. By O. PETTERSSON (Zeit. anal. Chem., 25, 467–478).—The principle of this method of determining the moisture and carbonic anhydride in atmospheric air consists in performing all the operations in a closed system, in which the influence of barometric variations and changes of temperature is eliminated by adjusting the pressure of the gas undergoing measurement to equality with that of a constant quantity in one part of the apparatus.

The

The apparatus consists of a pipette with its lower tube graduated, and connected with an adjustable mercury reservoir by a flexible tube. There is a stopcock at its upper end for the introduction of the air for analysis. Below this stopcock are branched in the upper tubes (furnished with stopcocks) two rather larger pipettes filled respectively with phosphoric anhydride and strongly dried soda-lime. lower tubes of these two pipettes are connected (by stopcock tubes) with the two ends of a sensitive differential manometer, which is a horizontal tube slightly curved and containing as index a drop of coloured sulphuric acid or high-boiling petroleum. The pipettes are all immersed in the same vessel of water. The whole apparatus having been filled with the air for analysis, the mercury having been adjusted to the zero of the graduated stem, and equality of pressure having been established by opening for a moment all the stopcocks, the measured volume of air is compressed into the phosphoric anhydride pipette by admitting mercury until it fills the measuring tube. In 20 minutes all the moisture will have been absorbed. The dried air is re-expanded into the measuring tube; the stopcocks to the manometer are opened, and the level of the mercury is adjusted till the pressure is again equal in all the pipettes. Since the quantity of gas in the soda-lime tube has remained unaltered it serves as a standard volume, although external pressure and temperature may have varied, and the reading of the mercury in the graduated tube at once gives the volume of the aqueous vapour absorbed. The same process is repeated with the soda-lime pipette, in which the carbonic anhydride is absorbed, and now the air in the phosphoric anhydride pipette is employed as the standard volume. M. J. S.

Assay of Iron Pyrites for Sulphur Available for Sulphuric Acid Manufacture. By J. C. WELCH (Analyst, 11, 209–213).—In one method, the pyrites is mixed with calcium hydroxide and heated in a tube in a current of oxygen; the contents of the tube are dissolved in hydrochloric acid and boiling water, and precipitated with barium chloride; the presence of lime and iron in solution is perhaps objectionable. The results are only approximate. In the second method, which answers very well indeed, the pyrites is heated in a current of oxygen, the issuing gases are passed through bromine dissolved in hydrochloric acid and water, and the liquid is then boiled and precipitated with barium chloride. The second method is better than the method depending on heating with fuming nitric acid, even in the case of lead sulphide. D. A. L.

Volumetric Determination of Sulphuric Acid. By H. WILSING (Zeit. anal. Chem., 25, 560—561).—-A measured excess of barium chloride is added to the neutral solution, and the excess is then determined by titration with sodium carbonate, using phenolphthalein as indicator. The liquid is to be boiled while titrating. Substances precipitable by soda must first be removed. M. J. S.

Volumetric Determination of Sulphates. By H. QUANTIN (Chem. News, 54, 233-234).-The solution of the sulphate under examination is well mixed with a hydrochloric acid solution of barium chromate to precipitate the sulphuric acid; it is then neutralised with ammonia to remove the excess of barium chromate. The filtrate, containing chromate equivalent to the original sulphate, is acidified with sulphuric acid and titrated with ferrous sulphate, using potassium ferricyanide as indicator. Various necessary precautions are noted.

D. A. L.

Determination of Nitric Acid by Absorption of Nitric Oxide in Standard Potassium Permanganate Solution. By H. N. MORSE and A. F. LINN (Amer. Chem. J., 8, 274-280).-The nitric acid is reduced by ferrous chloride and hydrochloric acid in a current of carbonic anhydride. As ordinary marble contains air that cannot be removed by boiling with water, the author uses a saturated solution of sodium hydrogen carbonate containing a quantity of the same salt in suspension. The nitric oxide and carbonic anhydride pass through an empty tube and a set of potash bulbs, the latter containing a strong solution of potassium carbonate to arrest all acid vapours. The washed gases are absorbed in two, long, slanting tubes containing a measured quantity of potassium permanganate. When the absorption is complete, the tubes are emptied and the contents decolorised by dilute sulphuric acid and a measured quantity of oxalic acid, the excess being titrated back with standard permanganate solution; the tubes are cleaned by rinsing with a portion of the sulphuric and oxalic acids. The method yields very accurate and concordant results.

H. B.

Lawrence Smith's Plan for Estimating Alkalis in Silicates. By P. HOLLAND (Chem. News, 54, 242-243).—The author's results indicate, firstly, that when carefully performed as directed, practically all the alkali is extracted at one operation; secondly, that the form of crucible recommended by Smith minimises the loss of salts by volatilisation. D. A. L.

Analysis of Silicates. By W. M. HUTCHINGS (Chem. News, 54, 173-174). The following method is recommended for mineral determinations in silicates. Alkalis are determined by flame colorations, metallic oxides by blowpipe tests, alkaline earths, alumina, and their approximate quantitative relation to one another and to iron by the following method:-A small quantity of the finely-powdered mineral is gently fused with seven times its weight of ammonium fluoride, the fluorides obtained are mixed with sodium carbonate and used in small quantities at a time in a platinum-wire loop before a

very hot flame, the beads are powdered and treated with water, alumina passes into solution, whilst iron and the alkaline earths remain undissolved. A mixture of cuprous iodide and sulphur in connection with the aluminium plate forms a very delicate test for small quantities of bismuth and lead. Both this mixture and Turner's flux keep good for many years. Glycerol is of more general use for boric acid testing than Turner's flux; in presence of copper for example. D. A. L.

Separation of Zinc from Iron, Cobalt, and Nickel. By P. v. BERG (Zeit. anal. Chem., 25, 512-519).-Hampe has published (Chem. Zeit., 9, 543) a process for precipitating zinc from a solution containing the above metals, by converting them into formates and treating with hydrogen sulphide. He, however, found a large quantity of free formic acid necessary to completely prevent the simul taneous precipitation of the other metals. The author shows that by diluting the solution until it contains only about 0.1 per cent. of zinc oxide, a much smaller quantity of formic acid (1 per cent. of 12 sp. gr.) ensures a practically complete separation, except in the case of cobalt, which requires a double precipitation.

Monochloracetic acid is still more efficient, a single precipitation being sufficient even with cobalt. To the dilute solution, heated to 50-60°, as much ammonia is added as is equivalent to the zinc present, then a small excess (about 2.6 grams to 450 c.c.) of monochloracetic acid; hydrogen sulphide is then passed slowly through the liquid.

In either case, filtration must be commenced immediately the hydrogen sulphide is in excess, and the precipitate must not be allowed to dry on the sides of the beaker. It is washed with water containing hydrogen sulphide and a little of the organic acid. The test analyses communicated are satisfactory, but the conditions were not varied. M. J. S.

Aluminium Sulphate containing Aluminium Hydroxide and Free Sulphuric Acid. By H. HAGER (Arch. Pharm. [3], 24, 852). -If the neutral sulphate contains any hydroxide, the crystallised salt gives a more or less turbid solution with 2 parts of distilled water. To detect free sulphuric acid, Jorissen's test is applied thus:-A couple of drops of gurjun balsam is warmed with 3 c.c. of acetic acid. About 0.25 gram of the powdered aluminium sulphate is added and warmed gently. In the absence of free sulphuric acid, a whitish or yellowish mixture is formed; in the presence of free acid, a blue coloration appears within a few minutes. J. T.

Determination of Aluminium in Presence of a Large Proportion of Iron. By R. T. THOMSON (Chem. News, 54, 252-253).— The methods depending on boiling with a caustic alkali and subsequent precipitation, or on direct precipitation by sodium thiosulphate, were found to be ineffectual, therefore the following methods of treatment are recommended for getting rid of the great bulk of the iron; the first works best except when much manganese is present, therefore under such circumstances the second method should be used. 1st method:

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