RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



On the estimation of organic matter by means of chromic acid, 



J. 15ARNES {Joiir. ;Soc. Chcm. Ind., 15 {1890), No. L\ pp. 82-84).— '£\iq 

 author's metliod is to add to 50 cc. of the sohition to be tested 25 cc. 

 strong- sulphuric acid and 10 cc. of a solution of potassium bichromate 

 containing (5.2 gm. of that salt and 50 cc. sulphuric acid to the liter. 

 The mixture is heated 1 hour on the boiling-water bath, after which 

 10 cc. of a standard ferrous sulphate solution is added and titrated back 

 with standard permanganate solution. A series of parallel experi- 

 ments with this and tlie permanganate method is given, from the 

 results of which the author concludes that the chromate method gives 

 a better measure of the organic carbon than the permanganate method. 

 The oxidation by permanganate was effected by 2i hours digestion at 

 70° in acid solution. — A. m. peter. 



On the preparation of ^vater free from ammonia, J. Barnes 

 {Jour. Soc. Chem. Ind.^ 15 {1890), No. 4, pp. 254). — The author prepares 

 ammonia-free water for nesslerizing without distillation by destroying 

 the ammonia compounds by means of an alkaline hypobromite. A 

 quantity of ordinary distilled water is put into a stoppered bottle and 

 bromin vapor is poured in until the water is just perceptibly colored 

 after shaking. A drop of strong soda solution is then added and the 

 bottle again shaken. After standing about 10 minutes a few drops 

 of potassium iodid are added to destroy the excess of hypobromite, 

 and the water will then be found free from ammonia and suitable for 

 use in nesslerizing. — A. M. peter. 



Note on a difficulty encountered in determining nitrogen by the 

 absolute method, W. R. Dunstan and F. H. Carr {Chem. News, 73 

 {1896), p. 128). — Wnen nitrogen was determined in the base aconite by 

 the absolute method, twice tlie amount of nitrogen corresponding to the 

 accepted formula was found, but the absolute method gave good results 

 on the hydrochlorid, as did also the soda-lime method on the base. An 

 analysis of the gas from the combustion of the base by the absolute 

 method showed it to Ite coiitamiiiated with methane. — e. w. kilgore. 



Combination of atmospheric and chemical nitrogen -\vith metals, 

 r. L. ASTANGLON {Chem. Ncics, 73 {1890), p. 115).— The, author found 



99 



