AGRICULTURAL CHEMISTRY. 507 



from extended studies of this method that to obtain accurate results by its use 

 the excess of molybdic acid solution should not be large, the precipitate should 

 be allowed to settle for 24 hours at ordinary temperature befoi*e being collected 

 <;n a tilter, and the precipitate and filter should be ignited at a moderate heat 

 over an Argand burner with constant stirring until the filter paper is com- 

 pletely burned. The compound thus obtained has the formula P20r,.24Mo03. 



An important question in the fertilizer industry, E. H. Schultze {Cliem. 

 Ztg.. SI (1907). No. 65, p. SOJ). — Attention is called to the importance of ac- 

 curate determination of the water-soluble phosphoric acid in superphosphates, 

 and it is asserted that no method for the determination of free phosphoric acid 

 has yet been proposed which gives reliable results. 



Determination of calcium oxid, magnesium oxid, and phosphoric acid by 

 means of the Zeiss refractometer, B. Wagner and F. Sciiultze (Ztsehr. 

 Aiialyt. Chcm., J,6 (1907), No. 8, pi). 501-508, figs. 3; abs. in C'hem. Zentbl., 

 1907, II. No. 10, pp. 8-J-}, 8.'f5). — The calcium is precipitated as oxalate, con- 

 A erted first to oxid and then to acetate, and in this form examined in the re- 

 fractometer. The magnesium and phosphoric acid are iii-ecipitated as am- 

 monium-magnesium phosphate and a sulphuric acid solution of the precipitate 

 examined in the refractometer. 



Dolomite and mag-nesite with reference to the separation of calcium and 

 magnesium, N. Knight and W. H. Wheeler (Proc. laica Acad. ScL, 13 {1906), 

 pp. 167-171). — Further experience with a method of precipitation of lime with 

 ammonium oxalate in solutions of calcium and magnesium chlorid as described 

 in Proceedings of the Iowa Academy of Science for 1903, p. 127, are reported, 

 with critical comments on other proposed methods and studies of conditions 

 affecting accuracy of the separation of calcium and magnesium. 



The estimation of lime and magnesia in water by volumetric methods, 

 W. T. Burgess {Anahjst, 32 (1907), No. 375, pp. 208-214, fl9- 1; abs. in Jour. 

 Chcm. Soc. [London], 92 (1907), No. 537, II, pp. 578, 579).— The method for 

 lime is based upon precipitation with ammonium oxalate and titration of the 

 excess of oxalate with potassium permanganate. The magnesia is determined 

 by precipitation with sodium hydroxid and determination of the alkalinity of 

 the supernatant solution. 



Chemical and bacteriological standards now in use in water analysis, 

 J. H. Kastle (Jour. Biol. Chcm., 3 (1907), No. 3, pp. XXXV, XXXVI).— The 

 various chemical and bacteriological standards now in use In water analysis are 

 reviewed and discussed. 



Logai'ithmic factors for use in water analysis, W. S. Hendrixson (Proc. 

 loica Acad. ScL, 13 (1906), pp. 173, 174). — A series of logarithmic factors for 

 recalculating results of water analysis is given. 



Investigations on the solubility of phosphoric acid and on the hygro- 

 scopicity of certain typical soils of Skaraborg County, G. Nannes (Inaug. 

 Diss., Univ. Konigsherg, 1906, pp. 98). — The investigations reported in full in 

 this paper have already been more briefly reported in separate articles (E. S. 

 R., 18, pp. 208, 318). 



Available plant food in soil, W. A. Hargreaves (Jour. Dept. Agr. So. Aust., 

 10 (1907), No. 7, pp. .',20-425; Dept. Agr. and Intel. So. Aust. Bui. 20. pp. 7).— 

 This article reviews investigations relating to chemical methods of determin- 

 ing available plant food in soils and states the history of such work to be a 

 " record of comparative failure." 



Analysis of egg yolk, N. A. Barbieri (Compt. Rend. Acad. Set. [Paris], 

 145 (1907), No: 2, pp. 133-135).— The author identified ui egg yolk tristearin, 

 triolein, cholesterin, crystallized sulphur, and a substance I'ich in phosphorus 



25729-^No. 6—08 2 



