RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



Estimation of nitrogen by Kjeldahl' s method (Trans. Guinness Res. Lab., 1 

 (1903), pp. 13-16; abs. in Jour. Chem. Sac. [London], 86 (1904), No. 500, II, pp. ',:,.",, 

 444)- — A distillation apparatus for use in Gunning's modification of the Kjeldahl 

 method is described, and precautions to be observed in order to prevent loss of nitro- 

 gen when dealing with bulky materials are given. 



Distilling apparatus for the Kjeldahl method of determining nitrogen, 

 E. Blanck (Chem. Ztg., 28 (1904), No. 34, p- 406, fig. 1; abs. in Jour. Chem. Sac. 

 [London], 86 (1904), No. 500, II, p. 444).— The digestion flask is fitted with a rub- 

 ber stopper double-bored to receive a tap funnel through which the alkali and the 

 potassium Bulphid are introduced, and for connection with the distillation apparatus. 

 At the beginning of the distillation water is allowed to run through the condenser at 

 full speed, but toward the end it is made to run slowly while the contents of the flask 

 are more vigorously boiled. 



A Kjeldahl apparatus, M. Siegfried (Ztschr. Physiol. Chem., 41 (1904), No. 1-2, 

 p}>. 1, 2, pi. 1; (ib». in Jour. Chem. Soe. [London], 86 (1904), No. 500, II, p. 444)-— 

 A device driven by water or electric motor for imparting a swinging motion to 

 Kjeldahl flasks to prevent bumping is described. 



A new method of estimating hippuric acid, T. Pfeiffer, C. Bloch, and R. 

 Riecke (Mitt. Landic. Inst. Univ. Breslau, 2 (1903), No. 2, pp. 27 3-293). —k. method 

 is proposed which, according to the authors, gives very accurate result*. 



Concerning the estimation of fat in animal tissues, feeding stuffs, and 

 the like, T. Pfeiffer and R. Riecke (Mitt. Landu: Inst. Univ. Breslau, 2 (1903), No. 

 2. />/>. 295-304, fig. 1). — A form of fat-extraction apparatus is described, which, accord- 

 ing to the authors, gives very satisfactory results. 



Methods of determining sulphur in organic substances, M. E. Pozzi-Escot 

 (Rev. din. ('him. Appl, 7 (1904), pp. 240, 241; abs. in Chem. Ceutbl., 1904, II, No. 1, 

 p. 62). — The author points out the disadvantages of various methods heretofore pro- 

 posed, lie describes a method of oxidation by means of nascent chromyl chlorid, 

 which gives good results with volatile compounds. In this method 1 gm. of the sub- 

 stance is mixed in a 500 cc. flask with 10 to 15 times its weight of pure dry chromic 

 acid. Then 20 to 25 cc. of pure and highly concentrated hydrochloric acid is added, 

 shaken vigorously for a few minutes, and allowed to stand 20 to 30 minutes. The 

 flask is connected with a reflux condenser and heated at boiling temperature for 10 

 minutes. If the chromic acid is in excess, the sulphur is completely converted into 

 sulphuric acid by this treatment. 



The determination of argon in atmospheric air, H. Moissan (Bui. Soc. Chim. 

 Paris, 3. ser., 31 (1904), No. 12, pp. 729-735).— Methods of taking samples of air and 

 determining argon are described, with results of examinations of samples of air from 

 widely separated parts of the world. The method is based upon the complete 

 absorption of oxygen and nitrogen by metallic calcium. A measured quantity of 

 approximately 1 liter of air is drawn through 2 tubes maintained at a low red heat, 

 the first of which contains a mixture of quicklime and magnesium and the second 



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