RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY. 



Quantitative volatilization of phosphoric acid, I'. Jannasch and E. Hei- 

 MANN (Bcr. Dciit. ('hci)i. G'r.s-r//., 39 {190r>). pp. 2625-2628 ; ahs. in Ghem. Centbl., 

 1906. II, No. 17, pp. 1357, 1358; Jour. Soc. Chem. Indus.. 25 (1906), No. 20, p. 

 1007). — In the method proposed 0.5 gm. of phosphate is carefully heated in a 

 flask in an open air bath with about 6 to 8 cc. of a mixture of 30 cc. of satu- 

 rated cane sugar sirup and 10 cc. of sulphuric acid (1:1), a stream of air 

 being passed through the flasli; until carbonization is complete and the mass is 

 dry. The flask is then connected with a receiver and heated to the highest 

 temperature it will bear, a stream of chlorin being passed through until no 

 more condensable products come over. Oxygen Is then substituted for chlorin 

 until all carbon is burnt. After cooling, 3 to 4 cc. of the acid sugar solution is 

 added and carefully spread over the inner surface of the flask and the above 

 process repeated. 



By this method the authors volatilized phosphoric acid completely from am- 

 monium and magnesium phosphates. The extension of the process to other 

 phosphates is lu'iiig investigated. 



The Woy method for the determination of phosphoric acid, G. B. Van 

 Kampen (Chem. Wcekhl, 3 (1906), pp. 576-579; ahs, in Chem. Centhl., 1906, 

 II, No. 17, p. 1357). — The author maintains that this method is as accurate and 

 satisfactory as the ordinary molybdic method. Like Woy, he finds the Ignited 

 residue to have a composition of 24M0O3P2O5. He considers Hundshagen's 

 method uusuited to volumetric analysis on account of the slowness of filtration 

 of the precipitate. 



Process for rendering mixed combinations of phosphoric acid and silicic 

 acid easily soluble, P. A. Newton (English Patent No. 91S3. Apr. 18, 1906; 

 ahs. in .Jour. ,S'oc. Chem. Indii.^., 25 (1906), No. 20, p. 997). — In this process the 

 raw phosphates are fused with artificial alkali silicates and lime in a regenera- 

 tive Siemens' furnace and the molten product is run directly into cold water. 

 It is stated that in the product thus obtained nearly all of the phosphoric acid 

 is citrate-soluble. 



Availability of phosphoric acid of the soil, (i. S. Fraps (Jonr. Amer. Chem. 

 aS'oc, 28 (1906), No. 7, pp. 832-834; «&s- '"" Jour. Chem. 80c. [London], 90 

 (1906), No. 528, II. p. 702). — A brief statement of the principal contents of this 

 article will be found in E. S. R., 17, p. Oil. 



The determination of nitric acid in soils, E. Gutzeit (Landic. Vers. Stat.. 

 65 (1906), No. 3-J,, pp. 217-219).— The inaccuracy of the determination of 

 nitrates in presence of humus, as is done for example in Buhlert and Fieken- 

 dey's method (E. S. It.. IT, p. 832), is pointed out. 



The determination of humus acids in soils by the Tacke method, C. K. 

 Van Daalen (Chem. Weekhl, 3 (1906). pp. 611-620; ais. in Chem. Centhl., 

 1906, II, No. 18, p. J.J58).— This method (E. S. R., 9, p. 32) is not considered re- 

 liable on accoimt of the slow and often incomplete evolution of carbon dioxid. 



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