AGBICULTUEAL CHEMISTRY AGROTECHNY. 609 



About the use of nitron for estimating nitric acid in nitrates, A. M. 

 Wasilieff (Zhui: Russ. Fis. Khim. Obshch., Chast Khim., ^2 (1910), No. ^, pt. 1, 

 pp. 567-570; abs. in Chem. Ztg., 34 (1910), No. 107, Repert., p. Ul).—The 

 author tested Busch's method (E. S. R., 16, p. 945) with the nitrates of po- 

 tassium, ammonium, magnesium, zinc, cadmium, manganese, aluminum, and 

 uranium, and found the results to be excellent. 



A reaction for nitrites, G. Armani and J. Baeboni (Abs. in Chem. Ztg., 34 

 (1910), No. 112, p. 994). — The method consists of adding to 10 cc. of the solution 

 to be tested from 4 to 5 drops of a saturated solution of benzidin in acetic 

 acid. The coloration obtained varies from a yellow to a red, depending upon 

 the concentration of the nitrites present. 



Determination of the nitrogen which is in esmbination as cyanamid and 

 dicyandiamid, A. Stutzeb and J. Soll (Ztschr. Angew. Chem., 23 (1910), 

 No. 40, pp. 1873, 1874). — This method, which was devised by N. Caro, is based 

 on the fact that the cyanamid may be precipitated as a silver compound from 

 an ammoniacal solution. The dicyandiamid is precipitated from the filtrate 

 also as a silver compound by the addition of potassium hydrate. The nitro- 

 gen is determined in the precipitates by the Kjeldahl method. 



Improvements in the exact determination of nitrogen in feces, I. K. Phelps 

 (Abs. in Science, n. ser., 33 (1911), No. 844, P- 342). — "The difficulties of an 

 exact aliquot and of loss of nitrogen in drying the viscous material are met by 

 each of two procedures. The first procedure consists in dehydrating the moist 

 mass by treatment with acidified alcohol and ether and filtration. The dry 

 residue is then sifted and the nitrogen determined in the residual material, 

 consisting of undigested material, in the powder obtained by sifting (which 

 represents the residue from food) and in the alcohol-ether extract. 



" The second procedure consists in partially decomposing the moist material 

 with concentrated sulphuric acid by heating in a steam bath until a homogeneous 

 mass is produced. This is then aliquoted and the nitrogen determined in the 

 aliquot. 



" The test of accuracy and adaptability of these procedures shows that they 

 are both excellent." 



See also a previous note (E. S. R., 23, p. 615). 



[Detection of phosphates with the molybdate reagent], R. E. Liesegang 

 (Chem. Ztg., 34 (1910), No. 130, p. 1158; abs. in Jour. 8oc. Chem. Indus., 29 

 (1910), No. 22, p. 1303). — ^As attempts have often been made without success 

 to use a nitric-acid solution of ammonium molybdate for detecting inorganic 

 phosphates in plant and animal tissues, the author tried the following experi- 

 ment: "A gelatin emulsion of tricalcium phosphate was poured into a test-tube, 

 and after it had solidified, several cc. of the molybdate reagent were poured on 

 top. At the surface of the gelatin a yellow skin of ammonium phospho-molyb- 

 date was formed, which after an hour was so firm that the underlying gelatin 

 could be melted without destroying it. No trace of the precipitate could be 

 seen in the gelatin. Though penetrable by phosphoric acid and nitric acid, the 

 gelatin was impermeable to the molybdate. The nitric acid, indeed, in one case, 

 had penetrated 20 mm. deep into the gelatin within an hour. The molybdate 

 reagent is therefore useless for the recognition of phosphates locally." 



The quantitative estimation of sulphur and phosphorus, C. G. L. Wolf and 

 E. OSTEEBERG (Biocheni. Ztschr., 29 (1910), No. 6, pp. 429-438).— A description 

 of a method for estimating sulphur and phosphorus in the same solution in bio- 

 logical products, and which, according to the authors, is as exact as either the 

 sodium peroxid method (E. S. R., 16, p. 639), or the Neumann method'' (E. S. 



o Ztschr. Physiol. Chem,, 43 (1904), No. 1-2, pp. 32-36, fig, 1. 



