1916] AGRICULTURAL CHEMISTRY — AGROTECHNY. 503 



cate its accuracy. The uranyl oxid can be easily recovered from the phosphate 

 precipitate. 



On the solubility of phosphoric acid in Thomas slag by extraction with 

 water containinff carbon dioxid, J. G. Maschhaupt (Verslafj. Landboutok- 

 OnderzoeJc. Rijkslandbouwproefstat. [Netherlands], No. 17 (1915), pp. 97-141, 

 figs. 5). — Analytical data indicating the amount of phosphoric acid of Thomas 

 slag soluble in water containing carbon dioxid, with various amounts of cal- 

 cium oxid and silicate present in the slag, are submitted in detail. The data 

 are discussed and the value of such a procedure for determining the available 

 phosphoric acid in slag fertilizers is emphasized. 



Experiments on the extraction of potash from wyomingite, R. C. Wells 

 (U. S. Geol. Survey, Prof. Paper No. 98-D (1916), pp. 37-40).— This paper 

 records experimental data on the chemical and mineral composition of wyo- 

 mingite (a lava occurring extensively in the Leucite Hills in Sweetwater 

 County, Wyo.), its behavior in water, and the effect of heating with gj'psum, 

 sulphuric acid, potassium bisulphate, alunite, calcium carbonate, calciimi 

 chlorid, magnesium chlorid, a bittern, and ammonium sulphate. The percen- 

 tage of the total potash extracted by heating with the various materials ranged 

 from 16.2 to 57, the largest amount being obtained by heating with alunite. 



It is indicated that while the experiments described can not all be considered 

 as commercial possibilities they may be suggestive to other investigators and 

 save the repetition of considerable preliminary investigation. 



A new apparatus for the determination of soil carbonates and new 

 methods for the determination of soil acidity, E. Tkuog {Jour. Indus, and 

 Engin. Chem., 8 (1916), No. 4, PP- S41-S45, figs. 2). — A new form of apparatus, 

 using the absorption tower previously noted (E. S. R., 34, p. 504), and its 

 manipulation are described in detail. 



Experimental evidence indicates that there exist in the soil two kinds of 

 acidity which are designated as active and latent. Methods for their sepa- 

 rate determination are proposed. It is further indicated that " soil acidity 

 is due to true acids and not selective ion adsorption by colloids ; the avidity of 

 the active acids in different soils varies greatly, which is of prime importance." 

 See also a previous note by the author (E. S. R., 34, p. 419). 



The analysis of Hawaiian soils, W. T. McGeorge {Haivaii Sta. Rpt. 1915, 

 pp. 33-36). — Slight modifications in the official methods to meet certain pecul- 

 iarities encountered in Hawaiian soils, notably the high content of iron, alumi- 

 num, titanium, and manganese, are presented, together with results secured 

 with four soils as to the influence of the time of digestion upon the solvent 

 properties of liydrochloric acid. 



On the determination of small quantities of hydrocyanic acid, M. O. John- 

 son {Jour. Amer. Chem. Soc., 38 {1916), No. 6, pp. 1230-1235, fig. i).— The 

 method described by Francis and Connell (E. S. R., 30, p. 709) has been shown 

 to require certain modifications, which the author has embodied in a convenient 

 and accurate procedure for the determination of small quantities of hydro- 

 cyanic acid. The potassium thiocyanate is extracted with acetone and then 

 determined colorimetrically by the production of the ferric thiocyanate. Any 

 organic coloring matter which may interfere with the color of the ferric thiocya- 

 nate is removed from the solution by extraction with ethyl acetate. 



The procedure was evolved in connection with some chemical work on cassava 

 at the Hawaii Experiment Station. 



The microscopy of vegetable foods, A. L. Winton, J. Moellek, and Kate 

 B, Winton {New York: John Wiley & Sons, Inc., 1916, 2. ed., rev. and enl., pp. 

 XIV+701, figs. 635). — This volume is the second edition of the work previously 

 noted (E. S. K., 17, p. 1096) and deals with the microscopy of vegetable foods, 



