RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



The estimation of nitrogen in feeding stuffs by the Kjeldahl 

 method, Gerlach and Suvern (C/*em. Ztij.. 18 {1804), No. 07, pp. 1902, 

 1903). — A number of determinatious of nitrogen by the Kjeldahl 

 method in cotton-seed meal, rice meal, and peanut meal showed that 

 varying the time of digestion from 2 to 12 hours caused an increase of 

 scarcely 0.1 per cent. The use of concentrated sulphuric acid contain- 

 ing 150 gm. of phosphoric anhydrid to the liter secured practically 

 the same results. The average of a number of blank determinations 

 showed that about 0,03 ])er cent of nitrogen was obtained from the air 

 in the digestion flask after 12 hours' digestion. The authors there- 

 fore conclude that the use of phosphoric anhydrid is unnecessary, and 

 that a digestion of from 2 to 3 hours is sufticient. The small additional 

 amount of nitrogen obtained after a long digestion is doubtless from 

 some compound other than albuminoids and would play a small part in 

 the economic value of the feeding stuffs. — j. P. street. 



Note on the Kjeldahl method for nitrogen, O. Kellner, O.Bott- 

 CHER, andGr. Diesselhorst [Chem. Ztg., 19 [1895), No. 3, p. 35). — An 

 answer to the above article of Gerlach and Siivern, showing that the 

 total nitrogen can not be obtained from products like cotton-seed meal 

 by digesting from 2 to 3 hours unless the sul[;huric acid contains phos- 

 phoric anhydrid and metallic mercury is added. — J. P. street. 



On the preparation of ammonium citrate solution, K. de Roode 

 {Jour. Amer. Chem. Soc, 17 {1895), No. 1, p. 47). — If in making the cit- 

 rate solution it is made decidedly alkaline with ammonia and allowed 

 to stand over night, in the morning the solution will be found to be 

 strictly neutral. The addition of a small quantity of salicylic acid 

 (1 gm. to 5 liters) before neutralizing will prevent the growth of fungus 

 in the solution. — j. p. street. 



Some facts observed in the determination of phosphoric acid 

 by the molybdic acid process, K. de Roode (Jour. Amer. Chem. Soc.j 

 17 {1895), No. 1, pp. 43-46). — Experiments are briefly reported from 

 which the author draws the following conclusions: 



"(1) Our present metliod [official] for deterinining phosphoric acid seems to give 

 results ■which are somewhat too high. 



" (2) The results obtained by using a large quantity of substance, and obtaining 

 large precipitates, are lower and somewhat more accurate than those obtained where 

 smaller quantities are employed. 

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