RECENT WORK IX AGRICULTURAL SCIENCE. 



CHEMISTRY. 



Methods of determining potash and the best precipitants of 

 platinum, A. Atterberg (Ghem. Ztg., 22 (1898), No. 54, pp. 538, 539). — 

 The article discusses the several methods that have been proposed for 

 the determination of potash, in the light of experiments made by the 

 author. The gravimetric methods are considered as a rule more satis- 

 factory than the volumetric methods. Of the gravimetric methods the 

 author considers that of Yilliers and Borg (E. S. R., 5, p. 538) the best, 

 of the volumetric methods that of de Koninck. 1 A method for deter- 

 mining potash directly in solutions containing iron and aluminum is 

 also described. After freeing the solution from silica, it is evaporated 

 to dryness with an excess of citric acid and sufficient platinum chlorid. 

 The citrates of iron and aluminum are then taken up with alcohol, and 

 the potash in the residue determined in the usual way. 



As the result of numerous experiments made by himself, the author 

 concludes that magnesium, mercury, and thioacetic acid are the best 

 precipitants of metallic platinum from platinic solutions. — j. T. 



ANDERSON. 



Modifications of the Kjeldahl method for determining nitrogen, 

 A. Atterberg- {Ghent. Ztg., 22 (1898), No. 50, pp. 505, 506). — The 

 author records a series of experiments which were instituted to deter- 

 mine the relative value of a number of oxidizing agents. He concludes 

 that the best means of oxidation is 20 cc. of concentrated sulphuric acid 

 with 15 to 18 gm. of potassium sulphate and some mercury. The 

 potassium sulphate may be added in the beginning except with sub- 

 stances which foam, when it should be added after solution has taken 

 place. The solution becomes clear in about 30 minutes. — j. T. Ander- 

 son. 



Contribution to investigations on manganese in minerals, 

 plants, and animals, P. Richard (Gompt. Rend. Acad. Sci. Paris, 120 

 (1898), No. 26, pp. 1882-1885).— -The method which the author has pre- 

 viously described (E. S. R., 9, p. 1023) was applied to a number of soils, 

 plants, and animal products with the result of showing the widespread 

 distribution of manganese in nature. The hymenomycetous fungi appear 

 to be especially rich in this substance, but other fungi and mosses are 

 well supplied with it. Among vascular cryptogams the ferns are the 

 most abundantly supplied. Of the gymuosperms the conifers are richest 

 in manganese. Of the augiosperms the Grammeae, Leguminosae, Rosa- 



Cbeiu. Ztg., 20 (1896), p. 502. 



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