RECENT WORK IX AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY. 



Practical agricultural chemistry, F. D. S. Robeetson (London, 1007, pp. 

 X+2I0; nv. in Chcnt. Xcics, Do (1907), No. 2^77, p. 237; Nature [London^. 

 76 (1907)) No. 1967, p. 2.^6). — This book attempts to give a complete laboratory 

 course of practical chemistry for agricultural students, iucludiug quantitative 

 analysis of solutions containing the commoner metals and acid radicals. Gravi- 

 metric analysis and simple volumetric determinations are treated, the more 

 technical part of the book dealing with analyses of soils and phosphatic ferti- 

 lizers, feeding stuffs, dairy products, oils and fats, sugars, tea, coffee, cocoa, 

 alcoholic beverages, and water. 



Agricultural chemistry. I. Nutrition of plants, K. Grauer (Agrikiiltur- 

 chonic I. PflunzcnerniihriuKj. Lcip-^ic, 1907, pp. 106 j rev. in Ostcrr. Vlicm. 

 Ztft.. 10 (1907), No. 18, p. 2.5S).— This little book gives in small compass a 

 simple but quite complete review of the pi'esent status of knowledge relating to 

 the chemical composition of plant substances, plant nutrition, chemical and 

 physical properties of soils, and fertilizers. 



Official and provisional methods of analysis, H. W. Wiley et al, ( U. S. 

 Dcpt. Ayr., Bur. Chcm. Bui. 107. pp. XXII1+2S0. fiffs. ;/).— This bulletin is a 

 revision of Bulletins Nos. 40 and G."» of the same Bureau, and includes all author- 

 ized changes and additions made prior to its publication. General and special 

 methods have been rearranged and consolidated, and repetitions or contradictory 

 material have been eliminated. 



Volumetric determination of nitrogen in nitrates, J. G. C. A'riens (Ztschr. 

 Analyt- Chem., .'i6 (1907), No. 6-7, pp. .'fl.'i-.'i20; abs. in Jour. Chcm. Soc. [Lon- 

 don}, 92 (1907), No. .')3S. II, it. 6ol). — The method described is based upon the 

 oxidation of ferrous ammonium sulphate when boiled with sulphuric acid and 

 nitrates. The extent of oxidation is measured by means of a 0.1 per cent solu- 

 tion of potassium ferricyanid, a blue coloration indicating excess of iron salt, 

 a brown color too little. " Separate portions of the nitrate solution are treated 

 . . . with increasing (or decreasing) quantities of the iron solution mitil with 

 one test a blue coloration is obtained on adding the indicator, whilst' the next 

 successive test, containing 0.1 cc. more of the iron solution, gives a brown 

 coloration " when observed within 30 seconds after adding the indicator. 



"The presence of considerable quantities of potassium sulphate, anunouium 

 sulphate, and sodium oxalate has no influence on the results obtained by the 

 method." 



The coloring of nitrifying organisms, W. Omelianski (Cerithl. Bakt. [f/c.l, 

 2. AM., 19 (1907), No. 7-9, pp. 26.3, 26-',).— A modification of Thesing's method 

 is described. 



Determination of phosphoric acid as phosphomolybdic acid, G. Jorgensen 

 (Ztschr. Analijt. Chcm., J,6 (1907). No. 6-7. pp. 370-392, pi. 1; ahs. in Jour. 

 Chem. Soc. [London], 92 (1907), No. 538, II, p. 652).— The author concludes 

 oOG 



