RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



Introduction to colloid chemistry, V. Posciil (Einfiihrnnfj in die Kolloid- 

 chemie. Dresden, 1910, 2. cnJ. ed., pp. 68). — A short text-book designed to serve 

 as an introduction to colloid chemistry for the student, teacher, and factory 

 superintendent. 



About the use of Eusch's nitron for the analysis of Chile saltpeter, L. 

 Badlberger (Ostcrr. Ungar. Zt.^chr. Zuvkcrindm. u. Landw., 39 (1910), No. 3, pp. 

 433-J,36, fig. 1).—The results show that this method (E. S. R., 16, p. 945) is accu- 

 rate when employed for estimating the nitric acid in Chile saltpeter providing 

 the latter does not contain a large amount of perchlorales. A microphotograph 

 of the precii)itate is shown. 



Determination of potassium as potassium platinic chlorid, P. Rohland 

 (Ztschr. AnaJyt. Chcm., J,9 {1910), No. 6. pp. 358-360).— The author observed 

 that barium chlorid is more easily soluble in methyl alcohol than in ethyl 

 alcohol, and made use of this fact for the determination of potassium as 

 potassium platinic chlorid in minerals, water, sulphates, etc. As the law of 

 mass action shows that with analyses such as these an excess of barium chlorid 

 must be employed.^the chief advantage in using methyl alcohol lies in that in 

 adding the barium chlorid (dropwise) the operator need not exercise extraor- 

 dinary care. In this manner a pure potassium i)latinic chlorid is obtained, 

 so that it is unnecessary to partially dissolve the salt, or to add a correction to 

 the results of the analysis. 



New methods for the analysis of commercial phosphates, J. M. Wilkie 

 {Jour. Hoc. Chem. Indus., 29 (1910), No. 13, pp. 796-799).— A discussion of 

 various methods, with particular reference to that of the author (E. S. R.. 21, 

 p. 8). 



Mechanical ag'itator for the analyses of phosphates, R. Frailong (Ann. 

 Cliim. Aiiuli/i., I.', (1910), No. 6, pp. 228, 229, figs. ,?).— A description and illus- 

 tration of the apparatus. 



Contribution to the chemistry and analysis of fats, A. Heiduschka (Ztschr. 

 Angew. Chem., 23 (1910), No. 21, pp. 990-992).— The results of tests with pure 

 fatty acids or a mixture thereof are given, including the estimation of the 

 Reichert-Meissl and Polenske figures, etc. 



Micro-chemical reaction of fatty bodies and Gram's reaction, M. Guerbet, 

 A. Mayer, and G. Schaeffer (Compt. Rend. 8oc. Biol. [Pans], 68 (1910), No. 

 8, pp. 353-356; abs. in Zentbl. Biochem. u. Biophiis., 10 (1910), No. -), p. 

 IJfl). — It was found that i)hosphatids, unsaturated fatty acids, and cerebrosids 

 give Gram's reaction. From the results the author presents the hypothesis 

 that bacteria only respond when they contain fat-like bodies. 



The estimation of the volatile acids in fermentation products of some 

 microbes by Duclaux's method, G. Seliber (Ahs. in Chcm. Ztg., 3!, (1910). No. 

 70, p. 622). — The author states that determining the volatile acids affords an 

 index as to the kind of organism present. Numerous tests were made with the 

 butyric acid bacterium and the Duclaux method with very concordant results. 

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