RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



Manual of the chemical analysis of rocks, H. S. Washington ( New York: 

 Jnlni Wiley & Sons; London: Chapman & Hall, Ltd., pp. IX-\-183). — "The object of 

 this book is to present to chemists, petrologists, mining engineers, and others who 

 have not made a particular study of quantitative analysis, a selection of methods for 

 the chemical analysis of silicate rocks, and especially those of igneous origin." in 

 general these are such as have proved simple and reliable in the experience of the 

 chemists Of the V . S. Geological .Survey and of the author. 



The more important of the methods and some of the principal operations are 

 described with greater explicitness than is necessary for the expert analyst. "In 

 this way it is hoped that it will be possible for an intelligent student, with some 

 knowledge of chemistry and a little analytical training, to be able to complete a sat- 

 isfactory analysis of an ordinary silicate rock without personal instruction and after 

 comparatively short practice." 



The estimation of potash in soils, plants, and fertilizers, F. P. Yeitcii 

 (Jour. Amer. Chem. Soc, 27 (1905), Xo. 1, pp. 56-61). — A comparison of Moore's 

 method (E. S. R., 10, p. 408) with the official method is reported. The results indi- 

 cate that the former method is simple, rapid, accurate, and of wide applicability. 



The determination of lime, A. W. B. ( Chem. News, 90 (1904), No. 2347, j>j>. 248, 

 249).. — Precautions to be observed in the accurate determination of lime by precipi- 

 tation with ammonium oxalate are described, and the influence of the presence of 

 various salts on the accuracy of the determination is discussed. 



The determination of organic carbon in soils, J. 11. Pettit and I. 0. Schaub 

 (Jour. Amer. Chem. Nor., ,.'>; 1 1904), Xo. 12, pp. I64O-I642) .—Parr's method for coal, a 

 substituting powdered magnesium for sulphur in the combustion was successfully used 

 with all soils .containing from 0.1 to 3.5 per cent of organic carbon. 



The reduction of perchlorate in the wet "way, B. S.iollema (Ztschr. Anorgan. 

 Chem., 42 (1904), p. 127; abs. in Chem. //</., 28 (1904), No. 97, Repert. No. 29, p. 

 353). — The reducing agent used is ferrous hydroxid, and the reduction is accom- 

 plished by boiling 0.4 gin. of the perchlorate for 3 hours in a glass flask in a paraffin 

 hath with a solution of 40 gm. of ferrous sulphate and 25 cc. of sodium hydroxid 

 solution of specific gravity 1.33, in 100 cc. of water. Twenty-five cc. of nitric acid 

 I sp. gr. 1.32 to 1.33) is then added and the solution heated for a short time, when 25 

 cc more of the same acid is added and the solution boiled for £ hour. The solution 

 is then made to definite volume and an aliquot titrated by Volhard's method. 



Soils and soil analysis, F. Hughes (Jam-. Khediv. Ayr. Soc. ami School Agr., 6 

 (1904), Xo. 4, pp. 138-142). — A brief discussion is given of the value of mechanical 

 and chemical analysis of soils. The methods used in the laboratory of the Khedivial 

 School of Agriculture are outlined and some of the more important results obtained 

 in an examination of Egyptian soils are reported. 



« Jour. Amer. Chem. Soc, 26 (1904), p. 294. 



038 



