AGRICULTURAL CHEMISTRY AGROTECHNY. 205 



for substances injurious to plants, and tlie volume weiglit of the ixiat. At the 

 same time a botanical, geological, macroscopical, and microscopical examination 

 of the peat is made. 



The determination .of water and citrate-soluble phosphoric acid in super- 

 phosphates, H. Pellet {Ann. Pharm. [Ranwez], 16. (,1910), pp- 106-203; abs. 

 ill Bui. Sci. Pharmacol., IS (.1011), No. 3, pp. 186, 187). — In estimating the 

 citrate-soluble phosphoric acid the author believes it advisable to treat the phos- 

 phate with ammonium citrate upon a boiling water bath. The results are a 

 little higher than those obtained with other methods. 



Note on the determination of the free acid in superphosphates, F. B. 

 Guthrie and A. A. IJamsay (Jour, and Proc. Roy. 8oc. N. 8. Wales, .'i3 (.1900), 

 No. 1, pp. 6.9-7'.'/). — During the course of experiments to determine the cause of 

 the reduction of the germinating power of wheat when brought into contact 

 with superphosphate before sowing, the authors made a comparative test of the 

 various methods in vogue for the determination of free phosphoric acid in 

 superphosphates. Those examined were the Gliicksmann, Thomson, Gerhardt 

 (E. S. R., 17, p. Ill), Herzf elder (E. S. R., 15, p. 335), and the direct titration 

 with sodium hydrate and utilizing various indicators. 



From their work the authors conclude that none of these methods is satis- 

 factory, and that although the Ilorzfi'lder method, which is based on tho ex- 

 traction of the phosphoric acid with ether and bringing it into an aqueous solu- 

 tion, utilizing methyl orange as the indicator, is the best, it yields only approxi- 

 mate results with pho.^phoric acid and is not neutral toward acid phosiihate. 

 They propose tentatively that a modification of the Herzfelder method be made 

 to determine the free phosphoric acid in superphosphates, and that ether be 

 used as thfe solvent for the free phosi)horic acid, converting the ethereal solu- 

 tion into an aqueous one and titrating the free acid with a standard alkali 

 solution, using sodium nliznrin suli)hounte as tho indicator. 



In regard to the analysis of Thomas slag powder, R. WoY (Ztschr. Offentl. 

 Chem-., 17 {1911), No. 5, pp. 86-88).— The author discusses the advisability of 

 eliminating some of the incongruous features of the Wagner method and 

 simply determining all the citrate-soluble phosphorus that can be dissolved out 

 of a given sample which has a definite degree of fineness without regard to 

 temperature of solvent, number of times to be shaken or rotated, or length of 

 time of exposure to solvent. He also points out the necessity of determining 

 anew the strength of the solvent to be employed, and, furthermore, that the new 

 method be made to serve also the purpose of detecting the presence of adulter- 

 ants in slag powders. The possible value of the Dubbers method is also pointed 

 out. 



The present status in regard to the valuation of Thomas slag powders, 

 R. WoY {Ztschr. Offentl. Chem., 16 {1910), No. 23, pp. 1,52-1,63; Chem. Ztg., 3f, 

 (WIO). No. 118, pp. 10-'i7, 10',8). — This is a critical discussion in regard to the 

 methods in use for the valuation of Thomas slag powders, with some data in 

 refoi-ence to the estimation of the citrate-soluble phosphoric acid according to 

 the various citrate methods, when utilized under varying conditions nnd with 

 particular reference to the silicic acid contained in the slag. 



The behavior of the hairs of certain cereals with hydrochloric acid, 

 Tj. Rosenthaler {Ber. Deut. Pharm. Gesell., 20 {1910), No. 7, pp. 368-371, fig. 

 1; al)s. in Chem. Ztg., 31, {1910), No. 11,5, Repert., p. 508).— It the hairs at the 

 tip of wheat are treated with concentrated hydrochloric acid (specific gravity 

 1.19) ribbon and spiral like forms spread from the hairs, or the hairs them- 

 selves curl up. This behavior could not be noted with the hnirs from barley or 

 rye, and therefore affords a means of distinguishing between these grains. 



