AGRICULTURAL 0HEMI8TRY. 1087 



one-sixth of the total quantity) ; apparently a soluble double phosphate is formed, 

 as dimagnesium phosphate is insoluble, and the amounl of alkali present would be 

 sufficient for the precipitation of the remaining dissolved magnesium under ordinary 

 conditions." 



The reactions of the three phosphoric acids, ( '. Arnold and <■. Werner 



(Chem. Ztg., . Vo. 104, pp. '■ : - ,: ~ tSt7; A >""'" 0, pp. 92, 



The authors' tests of published reactions having Bhown them to be generally 



unreliable, a new series of tests with the alkali Baits of ortho-, pyro-, and metaphos- 



phoric acids is given. 



On the compounds of pyrophosphoric acid, J. Cavalier {Compt. Rend. Acad. 

 [Paris'], 142 (1906), No. 15, pp. Four series of salts of this acid, which 



is taken to be tetrabasic P 2 II .are briefly described. Studies of the vapor densi- 

 ties of a series of alcoholic pyrophosphates show that they have a molecular weight 

 corresponding closely with the formula IM^K,. 



On the determination of citric-acid soluble phosphoric acid in Thomas slag-, 

 II. Fresenius ( Landw. Vers. Stat, 64 (1906), No. /. pp. 12-15). — A brief review is 

 given of studies of this method. 



The determination of phosphoric acid in fertilizers as phosphomolybdic 

 anhydrid, <;. Berth (Jour. Landv}^ 54 I 1906), No. 1, pp. 81-46; abs. in Chem. Ztg., 

 30(1906), No. 24, Repert. No. 7, p. 94). This article reports a study of the accuracy 

 of Neumann's method as applied to pure phosphates and Thomas Blag solutions 

 prepared in various ways. The method is reported to have given accurate results 

 under all conditions and is much simpler and more accurate than direct precipitation 

 of phosphoric acid as magnesium-ammonium phosphate. 



The determination of ammoniacal nitrogen in ammoniated superphos- 

 phates, Scheele and von Soxhlet I Landw. Vers. Stat., 64 I 1906 |, No. 1, pp. 15-17 ). — 

 A brief account is here given of the discussion of methods for this purpose at the 

 Munich meeting of the Association of t rerman Agricultural Experiment Stations. 



A simple method for the determination of nitric acid in nitrates, J. T. 

 Bornwater ( Chem. Weekbl, 8 (1906), pp. SO, SI; abs. in Chem. Centbl., 1906, J. No. 8, 

 /.'. 70S). — In the method proposed the nitrate is reduced by means of potash solution 

 and aluminium foil and the ammonia distilled in a Kjeldahl apparatus. 



On the need of uniform methods of titration in the determination of nitro- 

 g-en, B. Schulze (Landw. Vers. Stat., 64 I 1906), No. 1, pp. 85, 86).— A brief account 

 of the discussion of this subject at the .Munich meeting of the Association of < rerman 

 Agricultural Experiment Station.-, calling attention to lack of uniformity in kind and 

 strength of acids and alkalis used and of the desirability of greater uniformity in 

 these respects. 



The determination of potash by means of perchloric acid (Landw. Vers. 

 Stat., 64 (1906), No. 1, pp. 6, 7). — This method is described and its unanimous adop- 

 tion by the Association of < rerman Agricultural Experiment Stations is recorded. 



The detection and determination of chlorate in sodium nitrate, L. < rRiMBERT 

 (Jour. Pharm. el Chim., 6. ser., 28 I 1906), pp. 98-100; aba. in Analyst, 81 (1906), No. 

 861, p. 128). — Sodium nitrate is toted for presence of chlorate by shaking up the 

 solution with 1 drop of anilin, and pouring a little strong sulphuric acid down the 

 side of the tube. If chlorate is present an intense blue /one appears at the junction 

 of the liquids. ( Ihlorate is determined quantitatively by igniting the nitrate with a 

 little cane Bugar, extracting with water, and titrating for chlorids in the usual way. 



On the gravimetric determination of calcium, < ). Brunck (Ztschr. Analyt. 

 chnn., 46 (1906), No. /, /</'. 77 87, fig. 1). — Comparisons of various methods— direct 

 weighing, weighing as carbonate, sulphate, and fluorid — oi determining lime art- 

 reported. Direct weighing gave the most unsatisfactory result generally too high. 



oZtschr. Analyt. (hem., 37 I 1898), p. 317. 



