RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



Methods for detecting adulterations of bone superphosphates 

 -with other superphosphates, F. Dupont (Bui. Assoc. Chim. Sucr. 

 et Distill, 16 (1898-99), No. 8, pp. 767-771). — A summary and criticism 

 of the methods submitted in competition for the prize of 1,600 francs 

 offered by the Federation of Italian Agricultural Syndicates. The 

 competitors included 4 Americans, 3 Frenchmen, 2 Italians, 1 Swiss, 

 and 1 Austrian. The prize was awarded to H. Lasne, who submitted 

 a detailed chemical and microscopical method for the purpose. Among 

 those who submitted methods were A. P. Bryant (E. S. It., 8, p. 283), 

 H. A. Huston, and F. Martinotti (B. S. E., 10, p. 219). 



Estimation of pentoses, A. Gregoire and E. Carpiaux (Bui. 

 Assoc. Beige Chim., 12 (1898), pp. 143-151; abs. in Analyst, 21 (1899), Feb., 

 p. 39). — The authors give an account of their investigations on different 

 methods for determining pentoses, including the phenylhydrazin and 

 phloroglucin methods. In the gravimetric phenylhydrazin method 

 they found a small error due to the slight solution of the hydrazone 

 in the wash water. To obviate this they devised a gas gravimetric 

 process in which the nitrogen in the phenylhydrazin is determined 

 before and after the precipitation, and the difference calculated into 

 the amount taken up by the furfurol. For the determination of nitro- 

 gen in the phenylhydrazin from 4 to 4.5 gm. was dissolved in 250 cc. of 

 water, 25 cc. of the solution mixed with 20 cc. of concentrated hydro- 

 chloric acid, boiled for several minutes to remove the air, and intro- 

 duced while hot into a Schloessing apparatus containing 25 cc. of a 20 

 per cent solution of copper sulphate and a little hydrochloric acid. 

 The determination was made in the usual way. 



For the precipitation of the furfurol 81.5 gm. sodium chlorid was dis- 

 solved in about 400 cc. of water, 2 drops of acetic acid added and a 

 quantity of furfurol not exceeding 0.0 gm. After the addition of an 

 aqueous solution of phenylhydrazin (4 to 4.5 gm. in 250 cc.) the liquid 

 was made up to 500 cc. and shaken for at least an hour. The filtrate 

 was at once mixed with hydrochloric acid, which was found to prevent 

 the decomposition of phenylhydrazin acetate. It was then boiled to 

 expel the air, and 200 cc. containing 20 cc. of hydrochloric acid, was 

 used for determining the nitrogen, in Schloessing's apparatus, this 



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