of the experiment and the locality. Only in cases where a quantity of the rootlets had been torn off in removing the plants from the sand did the nitrogen in the moist sand exceed 3 per cent. of the whole. Bearing in mind the work of other experimenters, the authors believe that this loss of nitrogen, which is not observed in the germination of all seeds, is not a normal process of the growth of the plant, but is caused by processes of decomposition that depend on the presence of microbes. H. B.

Variations in the Chemical Composition and Physical Properties of American Oats. By C. RICHARDSON (Amer. Chem. J., 8, 364-374; compare Abstr., 1885, 585).-The grains vary considerably in weight, size, weight of husk, and in the way in which the husk encloses the grain, according to the environments of the plants. The chemical composition, however, is far more constant, and the proportion of husk and kernel and the compactness of the grain prove to be the all-important factors, and the weight per bushel the best means of judging of the value of the grain. No differences can be shown to exist such as might be expected between the largest and smallest oats, those having the lowest and highest proportion of kernel, &c. The detailed results are embodied in a series of tables. H. B.

Loss occasioned by Improper Methods of Pickling Wheat. By P. GRASSMAN (Bied. Centr., 1886, 766-774).-It is customary to treat wheat before sowing with solution of copper sulphate, which destroys the spores of bunt (Tilletia caries), but generally no special attention is paid to the quantity of sulphate employed; consequently much loss ensues, owing to the destructive action of the sulphate on the germinative power of the grain. Kuhn recommends that for every 5 bushels of wheat 1 lb. of sulphate be dissolved in 50 parts of water. In this solution, the wheat is to be soaked for 12 to 16 hours, after which, the liquid being first removed from above, the grain is to be dried for 24 hours. The liquid is to be removed from above, because the diseased grains and the fungus float to the top, so that if the liquid is drawn off from below, or if the grain is lifted out through the liquid, the damaged grain and spores will be mixed again with the healthy material. Grossman has examined the effect of prolonged drying and increased strength of solution on the vitality of the seed, and finds that both of these conditions are highly detrimental to the germinative power, and that where germination is not actually destroyed, the sprout will be unhealthy and weak, and germination will be delayed. Tables are given showing in detail the results of various mixtures and times of drying on the germination.

E. W. P. Nitrogen Compounds in Vegetable Soils. By BERTHELOT and ANDRÉ (Compt. rend., 103, 1101-1104).-The nitrogen in vegetable soils exists mainly in the form of insoluble compounds with carbon, hydrogen, and oxygen.

Sieved and air-dried soil was suspended in water, mixed with various proportions of hydrochloric acid, kept at different temperatures for varying lengths of time, and then filtered. The filtrate was

carefully neutralised with potash, then slightly acidified, and afterwards mixed with excess of magnesia, and the ammonia estimated by Schloesing's process. The ammonia was also determined in the soil which had been in contact with water only, and the difference between the two quantities gave the amount of ammonia formed by the action of the acid on the nitrogen compounds in the soil. The quantity of ammonia thus formed increases with the concentration of the acid, the time, and the temperature. The action of the hydrochloric acid is in fact precisely similar to its action on urea, asparagine, oxamide, &c. (this vol., p. 235), and hence it follows that the nitrogen in the soil exists in part at least in the form of amides.

After estimation of the ammonia, the liquid was carefully neutralised with sulphuric acid, evaporated to dryness on the water-bath, and the nitrogen in the residue estimated by means of soda-lime. This determination gives the amount of nitrogen present in the form of soluble amido-compounds, and it was found that the proportion of these compounds increases with the time of action of the hydrochloric acid and with its concentration. The amido-compounds thus rendered soluble by the action of the acid may be divided into two groups, one of which remains in solution when the liquid is neutralised with potash, whilst the other is precipitated with the ferric, aluminium and calcium oxides. In one experiment, the ratio between the nitrogen in the two groups was 23: 17.

Alkalis act on the nitrogenous matter in much the same way as hydrochloric acid.

C. H. B.

Manuring Rye with Thomas Slag and other Phosphates. By M. SIEVERT (Bied. Centr., 1886, 744-745).-The land had been manured in the previous year with farmyard manure, and in this season it received 30 lbs. P2O, and 10-5 lbs. N as ammonium sulphate or bone-meal per morgen. The phosphates applied were Thomas slag, bone-meal superphosphate, and Curaçoa phosphate. In all cases the slag brought the lowest, and the superphosphate the highest yield, and from a money point of view the super- and Curaçoa phosphates were the most advantageous. E. W. P.

Thomas Slag and other Phosphates as Manure for Moorlands. By RIMPAU and others (Bied. Centr., 1886, 732-742).-In the previous year, the phosphates failed to produce any definite result (Abstr., 1886, 1069). The experiments have been repeated in the succeeding year without added manures, so as to obtain information regarding the after-effect of the manures. It appears, then, that the after-action of Thomas slag and precipitated phosphate are alike. A set of experiments similar to those already described (loc. cit.) have been made by Wagenheim, from which it appears that as a manure for rye, slag is as good as precipitated phosphate; moreover, P. Wagner's law, that so long as an increase is obtained by the employment of increased quantities of phosphate, that increase will be in direct ratio with the increase of manure, was corroborated.

Another corroboration of Wagner's law was also obtained when rye was grown, and a distinct advantage of slag over precipitated phos

phate was noticed, in that the expenses were less with the former than with the latter. E. W. P.

Superphosphate Manuring for Sugar-beet. By A. NAUTIER (Bied. Centr., 1886, 742–744).-It was found in the neighbourhood of Peronne, where the land was rich (P2O, 034 per cent, N. 0·17, KO 0-53), that the addition of manures (nitre, ammonia, oil-cake, and phosphate) was unnecessary, as instead of an increase in the crop which paid for the manure the case was exactly opposite; there was a deficiency and loss. Neither was the percentage of sugar in the juice appreciably altered. But, on the other hand, in poor land deficient in phosphates, a gain was obtained by the use of superphosphate and natural phosphates, yet the total yield was lower, although the quotient of purity was higher than on the richer soil.

E. W. P.

Analytical Chemistry.

Filters with Greased Edge. By A. GAWALOVSKI (Zeit. anal. Chem., 26, 51).-By soaking the edge of a filter with paraffin, wax, or fat (free from ash), the tendency which some precipitates have to creep over the edge is entirely removed. M. J. S.

Method of Estimating Fluorine. By A. CHAPMAN (Chem. News, 54, 287).—The ignited substance is pulverised and repeatedly treated with 10 per cent. hydrochloric acid, the combined extracts are made up to a definite volume, and an aliquot part treated with acid ammonium acetate, which precipitates calcium fluoride; the precipitate is washed, dried, ignited and weighed. As calcium phosphate is not precipitated under these circumstances, the method is well adapted. for the analysis of commercial phosphates. D. A. L.

Reagents for detecting Minimal Quantities of Active Oxygen. By C. WURSTER (Ber., 19, 3195–3205).-Tetramethylparaphenylenediamine, C.H.(NMe2)2, is converted by all oxidising agents into a blue-violet dye, only capable of existing as a salt, C&HNMeCi

Me-CH2. This, when further oxidised, changes from

red-violet to red, and finally becomes colourless. It can be reduced to the original base. Paper soaked with a solution of tetramethylparaphenylenediamine forms a very delicate test for active oxygen. It shows the presence of active oxygen in the air, in the neighbourhood of flames, in the sap of plants, and in the human skin. The moist paper is also coloured by silver oxide and by red-lead. Solution of copper sulphate or the dry salt, spongy platinum, wood charcoal, and many other powders, aldehyde, ethereal oils, some alcohols and acetone colour the paper. It is also coloured by most disinfectants in sunlight, by chlorophyll, and by some ferments.

Chloric and nitric acids do not colour the paper quickly; but when salts of these acids are treated with strong sulphuric acid the gases evolved rapidly oxidise the diamine.

When hydrogen peroxide and tetramethylparaphenylenediamine, both in the purest possible state, are brought together the solution is scarcely coloured; on adding paper or a chip of wood, an intense coloration is produced, which lasts for days. Very dilute nitrite solution (1: 1000 or 1: 10000) gives an intense coloration, but is decolorised again almost immediately. Even a solution of a nitrite diluted to 1: 10,000,000 is slowly decolorised.

Dimethylparaphenylenediamine, when oxidised, yields a fine red dye; this changes to a violet or blue dye when kept, or when heated. When the free base is brought into contact with the skin, the latter is often coloured brown or black in a short time. Paper prepared with the diamine remains blue-violet for two or more hours in a mixture of hydrogen peroxide, and acetic or lactic acids; decolorisation takes place quickly on adding salt to the solution; this is probably due to the liberation of hydrochloric acid.

The oxidation of the methyl-derivatives of phenylenediamine is quantitative, and can be shown by potassium permanganate in hydrochloric acid solution. N. H. M.

Influence of Copper on the Estimation of Sulphur. By W. F. BRUGMAN (Chem. News, 54, 290–291).—The author's experiments indicate that when copper is present in quantities not exceeding 1 per cent. it does not interfere with the working of the "hydrogen sulphide method" of estimating sulphur in iron and steel. There has been much difference of opinion on this point. D. A. L.

Eggerzt's Method of Estimating Sulphur in Iron. By G. MÖLLER (Chem. Centr., 1886, 489-490).—The author has reinvestigated this method, and finds the results to be unsatisfactory.

Estimation of Sulphur in Coal and Coke. By A. J. ATKINSON (J. Soc. Chem. Ind., 5, 154–157).—The author's method is a modification of Nakamura's process of heating pulverised coal in contact with sodium carbonate, whereby the coal rapidly undergoes complete atmospheric oxidation, the combustion of the carbon being effected at a dull red heat over a spirit-lamp (compare Trans., 1879, 785). The difficulty with which the heat from a spirit-lamp can be evenly distributed over the whole of the test, suggested to the author that the combustion could be more easily conducted in a muffle through which a gentle current of air is made to pass. The author has also made a series of experiments with the object of proving the applicability of this method to the estimation of the sulphur contained in pyrites, but the results have hitherto been far from satisfactory. If by some simple device, the complete oxidation of the sulphuric acid could be secured, the amount of this acid might be determined by finding the quantity of standard sulphuric acid required to neutralise the excess of sodium carbonate, and deducting that amount from the quantity

required to neutralise the whole of the sodium carbonate weighed D. B.

out.

The

Estimation of Sulphur and Impurities in Coal-gas. By T. FAIRLEY (J. Soc. Chem. Ind., 5, 283-286).-The author's process of estimating sulphur in coal-gas consists in using a very dilute solution of hydrogen peroxide, run in at the top of the referees' apparatus, and the plain flame under the trumpet without ammonium carbonate. The oxidising effect is very complete, even with solutions containing less than 1 per cent. of peroxide. The equation is H,O,+ SO, = H2SO,, and hence the liquid may either be titrated with standard alkali, or acidified and precipitated with barium chloride. method may be used either intermittently or continuously. In the former case the sulphuric acid in the condensed liquid and washings may be determined either by titration, or precipitation, or both; and in the latter, the receiver being changed, the volume of gas required is burnt, and then the sulphuric acid is estimated in the liquid collected, without disturbing the rest of the apparatus. The estimations of carbonic anhydride and of ammonia in coal-gas are made by processes substantially the same as those described in text-books. Where the carbonic anhydride is over 1 per cent., approximately accurate results may be obtained by the use of Bunte's gas burette. When the gas has been purified by lime, the carbonic anhydride may fall under 1 per cent., and then a standard solution of barium hydroxide should be used, contained in an ordinary absorption apparatus arranged to give as small bubbles of gas as possible. After passing a measured volume of the gas through a measured quantity of the barium solution, and allowing the precipitated carbonate to settle, a portion of the clear liquid may be titrated. The loss of alkalinity gives the carbonic anhydride present in the gas.

D. B.

New Reaction of Thiosulphates. By L. L. DE KONINCK (Zeit. anal. Chem., 26, 26).—A mixture of an alkaline thiosulphate with aqueous potash or soda yields an alkaline sulphide when treated with aluminium. M. J. S.

Detection of Ammonia, Nitric or Nitrous Acids, and Thiosulphuric Acid in a Mixture of Alkaline Salts. By L. L. de KONINCK (Zeit. anal. Chem., 26, 26—27).—Aqueous soda is added, and the mixture boiled in a fractionating flask connected with a U-tube containing Nessler solution. When all the ammonia is expelled, aluminium foil is introduced, and the presence of the nitrogen acids is recognised by testing a second distillate for ammonia. Finally, the tests for a sulphide are applied to the residue in the flask (compare preceding Abstract). M. J. S.

Determination of Ammonia in Arable Soil. By W. KNOP (Zeit. anal. Chem., 26, 1–9; compare Baumann, this vol., p. 82.)— The determination of ammonia in soil by means of hypobromite is complicated by the fact that clay, especially when ferruginous, undergoes contraction when shaken with a strongly alkaline solution. This