RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



Technical methods of chemical analysis, edited by G. Lunge et al., trans, 

 and edited by C. A. Keane et al. {London, 1911, vol. 2, pts. 1, pp. XXVII+610; 

 2, pp. XII +611-1252, figs. HiO). — Among tlie subjects taken up in these parts 

 of this work (B. S. R., 21, p. 105) are artificial manures, feeding stufEs, am- 

 monia, and synthetic and naturally occurring organic dyes. 



Solubility determinations in agricultural chemistry, A Rindell {Akad. Ein- 

 ladungsschr. Helsingfors, 1910, pp. 67; abs. in Jour. Soc. Chem. Indus., SI 

 {1912), No. 2, p. 8'i). — This is a general discussion of solubility, its importance 

 in agricultural chemistry, and the methods of determining solubility. 



In experiments with Thomas slag it was found that the phosphoric acid was 

 present apparently in a very insoluble form. " Experiments with pure water 

 after 55 days' stirring at 25° C, using 10 gm. of substance per 1,000 gm. of 

 water, show that with Thomas meal 0.1790 gm. of calcium oxid and 0.0316 

 gm. of phosphoric acid dissolve, whereas from raw phosphates the solution only 

 takes up from 0.00075 to 0.0025 gm. of phosphoric acid, except in the case of 

 Mexico phosphate, which is more soluble than Thomas meal. These phosphates 

 will be perhaps slightly more soluble in soil solutions, but water is far pref- 

 erable as a solvent in such cases to the 2 per cent citric acid usually employed, 

 in which the soil constituents have too great a solubility. Stress is laid on the 

 difficulties of finding solubility methods applicaJ3le to agricultural problems 

 to which no theoretical objections can be raised, and the importance of intro- 

 ducing physical chemical methods into these conceptions is emphasized." 



A modification of the diphenylamin test for nitrous and nitric acids, W. A. 

 Withers and B. J. Ray {Jour. Amer. Chem. Soc, S3 {1911), No. 5, pp. 708- 

 711). — This material has been noted from another source (E. S. R., 25, p. 804). 



Determination of lithium, W. W. Skinnek and W. D. Collins ( U. 8. Dept. 

 Agr., Bur. Chem. Bui. 15S, pp. 38). — ^After a comprehensive review of existing 

 methods for lithium, particularly in mineral waters, a modification of the 

 Gooch method which has been developed and used in the Bureau of Chemistry 

 is described. This method was found to be entirely satisfactory where weigh- 

 able amounts of lithium were present. 



Pyridin as a solvent for the lithium salts was foimd to be objectionable on 

 account of its unpleasant odor, the difficulty of preparing and keeping it 

 sufficiently free from water, and the fact that in water analysis usually very 

 small quantities of lithium chlorid are to be separated from large quantities of 

 sodium and potassium chlorid. 



For the spectroscopic estimation of lithium the methods of Ballman, Bell, or 

 Foehr, when modified to employ the alkalis as extracted by amyl alcohol, were 

 found satisfactory. The quantitative spectroscopic method, however, is not 

 deemed preferable to the Gooch method where weighable amounts of lithium 

 are present. 



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