ammonium sulphate; and the quality of the roots from the various plots was ascertained by selecting proportionate numbers of large, medium, and small roots from each plot, and testing the juice by the hydrometer and in the saccharimeter. The chief results of the experiments are that the continuously unmanured plots of both series yielded very small crops of small roots poor in sugar, namely, 13900 and 10100 kilos. of roots per hectare, density of juice 6.9 and 7.2, percentage of sugar in juice 158 and 146. The mean percentage of sugar in the juice of the roots from the Grignon seeds was 17·7, and in the juice of the roots from the Vilmorin seeds 171, so that it is evident a good sample of seed may be relied on by the farmer for at any rate a second harvest. Both series of plots proved that on the light soil of Grignon, moderate dressings of farmyard manure, with or without the addition of sodium nitrate or ammonium sulphate, produced considerably larger crops than the sodium nitrate or ammonium sulphate alone, and that the roots grown with the farmyard manure were by no means poor in sugar, the juice containing 18 to 19.5 per cent.; 30000 kilos. farmyard manure per hectare, or 20000 kilos. with 200 kilos. sodium nitrate, were found to be the best dressings; a larger quantity of farmyard manure diminished the crop, and ammonium sulphate proved, as it generally has done at Grignon, decidedly inferior to sodium nitrate. J. M. H. M.

Iron in Wine. By SAMBUC (J. Pharm. [5], 16, 344-345).-A wine from Seyne (Var.) from an American vine, the Jacquez, was found to contain, per litre :-Alcohol, 67.54 grams; dry extract at 100°, 20-50; acidity in terms of sulphuric acid, 6-20; total ash, carbonated, 2.60; anhydrous ferric oxide, 0·11. The iron was determined both gravimetrically and volumetrically. The usual amount of iron in wines is equivalent to 0·01-0·02 gram of ferric oxide.

J. T.

Nitrates in Soils and Water. By E. BRÉAL (Ann. Agronom., 13, 561-568). The author has applied the mode of detecting nitrates described in a previous memoir (Abstr., 1887, 1138) to the study of the arable, pasture, and forest soils, and the waters in the neighbourhood of Baden, Switzerland. A few cubic centimetres of the sulphophenol reagent in a stoppered bottle, and some strips of prepared filter-paper, are sufficient to show that nitrates are abundant in the arable soils, deficient in the meadow soils, and almost absent from the forest soils. He attributes the deficiency in the last two descriptions of soil to the excess of organic matter hindering nitrification, and to the rapid consumption of what nitrates are formed by the perennial crops. The mountain streams are free from nitrates, and so is the water of a hot mineral spring highly charged with sulphate of lime. J. M. H. M.

Sulphur and Phosphorus in Plants, Soils, and Moulds. By BERTHELOT and ANDRÉ (Compt. rend., 105, 1217-1222).—Sulphur may exist in plants, soils, and moulds, in the form of sulphates directly precipitable as barium sulphate; in the form of compounds analogous to the ethyl sulphates from which the sulphur is obtained

as sulphate by hydrolysis or oxidation; in the form of salts such as sulphides, sulphites, and thiosulphates, which can be converted into sulphates by oxidation in solution; and in the form of carbon-compounds such as taurine, cystin, albumin, &c., the sulphur in which is not converted into sulphate by oxidation in solution.

In order to estimate the total sulphur or phosphorus, the substance previously dried at 100° is burnt in a current of oxygen in a glass tube, the products of combustion being conducted through a column of pure anhydrous sodium or potassium carbonate. Care must be taken that the temperature does not rise sufficiently high to fuse the alkaline carbonates in the ash. When combustion has ceased, the current of oxygen is continued for some time in order to convert any alkaline sulphides into sulphates. The contents of the tube are dissolved in water, acidified with hydrochloric acid, and precipitated with barium chloride. In the filtrate from the barium sulphate, the phosphorus is precipitated by means of ammonium molybdate, and is afterwards converted into magnesium pyrophosphate.

The soil examined contained 1418 gram of sulphur per kilo., but 1 per cent. hydrochloric acid only extracted one-seventh of this, and concentrated nitric acid dissolved very little more.

The mould contained 6-156 grams of sulphur per kilo., of which 0.947 gram was soluble in cold dilute hydrochloric acid, and 2:0213 in concentrated boiling nitric acid.

One of the specimens of the plant, Mercurialis annua, contained 10.768 grams of sulphur per kilo., 3040 being soluble in cold dilute hydrochloric acid. Another specimen contained 6:584 grams per kilo., 2.834 grams being soluble in cold 1 per cent. hydrochloric acid and 4.554 in boiling concentrated nitric acid.

The sulphur existing as sulphate is in all three cases only a small proportion of the total quantity, and the sulphur convertible into sulphate by oxidation in solution, although greater, is still only a fraction of the total amount.

Phosphorus may exist in plants, moulds, and soils, as phosphates soluble in water or acids; as ethereal compounds yielding phosphates on hydrolysis or oxidation; as phosphides or phosphites, &c., which can be oxidised to phosphates in solution; and as organic compounds which cannot be converted into phosphates in the wet way.

The soil examined contained 0641 gram of phosphorus per kilo., 0134 gram of which was soluble in hydrochloric acid of 1 per cent., 0-420 in hydrochloric acid of 10 per cent., 0-603 in boiling concentrated nitric acid. The total phosphorus is much greater than that existing as phosphate, and it is not completely oxidised by nitric acid.

The mould contained 3-091 gram per kilo., 2·328 being soluble in cold dilute hydrochloric acid, and 3085 in hot concentrated nitric acid. In this case, the proportion of phosphate is very large, and it is noteworthy that concentrated nitric acid removes the whole of the phosphorus. This last result is, however, probably abnormal.

The first specimen of the plant contained 2812 grams of phosphorus per kilo., 1668 gram being soluble in cold dilute hydrochloric acid. The second specimen contained 5.440 gram per kilo., 2-963 being soluble in cold dilute hydrochloric acid, and 4.154 in hot con

centrated nitric acid. The proportion of phosphorus depends largely on the age of the plant. The last specimen contains twice as much as the mould, and nine times as much as the soil. The proportion of soluble phosphates is greater than in the soil, and is comparable with that in the mould.

From these results, it is evident that sulphur and phosphorus, like nitrogen, exist ia plants, moulds, and soils, in several different forms. C. H. B.

Analytical Chemistry.

Polaristrobometric Analysis. By H. LANDOLT (Ber., 21, 191– 220). The specific rotation of nearly all circularly polarising solutions may be expressed in terms of-(1.) The percentage q of the inactive solvent, [a] = A + Bq + Cq. (2.) The percentage p of the active substance, [a] = a + bp + cp2. (3.) The concentration c, [a] A1 + B1c + С1c. In many cases, the third term may be neglected. The two last equations may be used for either concentration or percentage composition, since c = pd, where d is the specific gravity of

the solution.

=

In determining from the rotation the amount of substance in solution, the following cases have to be distinguished :—

I. A solution may contain a single active substance in an inactive solvent. This is the most general case, and the specific rotation is as a rule constant, that is, the angle of rotation is proportional to the concentration, as is the case for aqueous solutions of cane-sugar, milksugar, maltose, raffinose, dextrose, lævulose, invert sugar, and galactose. The specific rotation is, however, not always constant, but sometimes a linear function of the concentration, as, for instance, for solutions of nicotine and camphor in alcohol.

II. Solution of an active substance in two inactive solvents. The specific rotation of nearly all active substances being unequally influenced by different solvents, the action of each solvent alone on the rotation has to be separately considered. These will be [a] = A + Bq and [a] = A + Biq, the constant A being the rotation of the pure active substance and the same in each case. Hence if q and qı are the weights of two solvents contained in 100 parts of the mixture, the specific rotation will be [a]m = A + Bq + Bigi. This presupposes each solvent to act perfectly independently of the other, which, however, only happens in the case of cane-sugar, the rotation of which is the same for all solvents. In other cases, the value of [a]m lies irregularly between [a] and [a], as, for instance, for narcotine in 1 vol. alcohol to 2 vols. chloroform, or it attains a maximum higher than either [a] or [a], as for cinchonidine in the above solvents or cinchonidine nitrate and hydrochloride in mixtures of alcohol and

water.

III. Solution of two active substances in an inactive solvent.

Firstly, the combined weight of the two substances in 100 c.c. solution may be known. Let the specific rotation of the solution be [«], and the mixture contain a per cent. of one constituent of the specific rotation [a], and y = 100 x of the other constituent of the specific rotation []. Then [a]xx + [a]y (100 — x) = 100 [a], from which x and y are obtained in terms of [a], [a]r, and [a]y. Instances of this are solutions of cane-sugar and raffinose and quinine and cinchonine sulphates. Secondly, the combined weight of the two active substances may be unknown, and the analysis is then effected by measuring the rotation of the solution, and converting one or both of the constituents into another optically active substance by inversion, and again measuring the rotation. If only one constituent undergoes inversion, if and the angles of rotation for unit concentration of each constituent be known, p the rotation of the inverted substance, and c, and Cn the concentrations required, we have—

Before inversion, ici + Pucu = a

After inversion, pkc1 + Puc =α

from which c1 and c1 may be calculated. This is true for solutions of cane-sugar and invert sugar and cane-sugar and dextrin, the canesugar being the substance inverted. If both constituents undergo inversion, then if p is the rotation of the second inverted substance

This is true for a solution of raffinose and cane-sugar.

IV. Analysis of inactive substances in solution. This would be effected by measuring the influence of certain inactive substances on substances of known rotation, such, for instance, as the action of boric acid on tartaric acid solutions. Little has been done in this direction, and no attempt at formulating the above influence can at present be made. H. C.

Correct Analysis of Superphosphates. By J. RUFFLE (J. Soc. Chem. Ind., 6, 491-494 and 704-705).-In furtherance of his investigations on moisture and free acid in superphosphates (this vol., p. 87), the author suggests the following method of analysing superphosphates:(1.) Moisture: estimated by calcium chloride in vacuum. (2.) Soluble phosphoric acid: estimated by direct determination. (3.) Insoluble phosphate: estimated by direct calculation from the amount of insoluble phosphoric acid after evaporation to dryness with hydrochloric acid and re-solution with hydrochloric acid. (4.) Calcium sulphate: estimated by determining the whole sulphuric acid present and calculating this into anhydrous calcium sulphate. (5.) Sand: estimated by evaporating to dryness with hydrochloric acid and re-solution in hydrochloric acid. (6.) Combined water and organic matters, including the uncombined calcium oxide: estimated by difference. (7.) Alkalis, magnesia: amounts as determined.

By this plan no more work is introduced than is practised at

the present time, whilst the statements 1, 2, 3, 4, 5, and 7 will be true from direct determination, and the commercially unimportant "combined water and organic matter" will not be attempted; hence false statements will be avoided.

The author is of opinion that the calcium oxide existing as monocalcium phosphate in ammoniated phosphates may be wholly passed over, and the total calcium oxide, less the amount of the insoluble phosphate, be calculated out to calcium sulphate. D. B.

Separation of Zinc from Nickel and Manganese and Estimation of Nickel. By T. BAYLEY (J. Soc. Chem. Ind., 6, 499).— A good separation of zinc from nickel and from manganese may be made in a hot solution containing free phosphoric acid by precipitation with hydrogen sulphide. Cobalt has a tendency to go down in small quantity with the zinc. In order to precipitate nickel from solutions, the author recommends the addition of ammonium sulphide until the last drop renders the liquid alkaline; this is followed by ammonium benzoate, and afterwards by a few drops of hydrochloric acid. In this solution, the nickel is completely precipitated as sulphide. The latter is heated in a porcelain dish, dissolved in nitric acid, evaporated, ignited, and weighed as sulphate. The ignition should be effected at a low red heat, and the dish allowed to cool. The sulphate is then treated with sulphuric acid and submitted to a further short ignition. Success would appear to depend on the shortness of the second ignition.

D. B. Reaction of Iron with Nitric Acid. By T. BAYLEY (J. Soc. Chem. Ind., 6, 499-500).-When an assay of "nitre" in sulphuric acid is made in the nitrometer, an error is caused by absorption of nitric oxide when the acid contains iron. Nitric oxide, shaken with mercury and pure sulphuric acid, suffers no absorption, nor does mercury pass into solution in the acid unless the acid contains a small quantity of iron. On copiously diluting the acid by the addition of air-free water, and subsequently adding a solution of a ferricyanide to the cooled acid liquid, the blue reaction is readily obtained. The mercury seems to take no part in the reduction of the ferric salt, since the results can be equally well obtained if pure nitric oxide is passed through a set of Geissler bulbs charged with sulphuric acid containing ferric sulphate. The sulphuric acid in this case, as in the nitrometer, assumes a purple tint, which is characteristic of the reaction when it takes place in the acid, but not in the aqueous solution.

D. B.

Action of Oils on Polarised Light. By W. BISHOP (J. Pharm. [5], 16, 300-301).—Besides resin and castor oils, there are two others which very perceptibly affect polarised light. Thus in a tube of 20 cm. long colza oil gave a rotation of -16° to -2·1o, and sesame oil gave from +3.1° to 90°. Of several other vegetable oils examined none gave as much as 1·0°. In the case of certain linseed oils, when found to have dextrorotative power, they should be examined for sesame oil before concluding that resin oil has been added.

J. T.