AGRICULTURAL CHEMISTRY AGROTECHNY. 805 



The method has for its principle the interaction of nitrates and anhydrous 

 formic acid, and proceeds according to the following equation : 



2KN03+6H.CO=H=N.O+4CO=+5HoO+2H.CO=K. 



Analysis of calcium cyanamid, A. Stutzer {Chem. Ztg., 35 (1911), No. 76, 

 p. 69^; abs. in Jour. Soc. Chem. Indus., 30 (1911), No. 1',, p. 9i3).— The results 

 of determining the total nitrogen in calcium cyanamid by the Kjeldahl method 

 were found to agree well with those obtained by the salicylic acid method. 

 This is contrary to Monnier's findings, who obtained results 1 per cent too low 

 with the former method. Only 0.14 per cent of nitrogen instead of 1.52 per 

 cent, as stated by Monnier, was found to be derived from the carbon used in 

 the manufacturing process. 



The use of silver phosphate as a standard for phosphoric acid, and a 

 critical study of the gravimetric magnesium method for the estimation of 

 phosphoric acid, W. C. Dumas (Chem. Engin., 12 (1910), No. 6, pp. 185-190, 

 fig. 1; abs. in Chem. Ztg., 35 (1911), No. 18, Repert., p. 65). — ^As the controlling 

 substances of these determinations the author utilized silver phosphate, and as 

 a result of the work he points out that the composition of magnesium ammo- 

 nium phosphate may vary to a considerable extent. The proper composition, 

 however, may be obtained when the precipitation is made from a neutral 

 solution. The precipitate obtained from a weakly alkaline solution was found 

 to be high in phosphoric acid and low in magnesium ; some of the phosphoric 

 acid is volatilized on ignition. In rapidly precipitating from a neutral or 

 slightly alkaline solution the phosphoric acid content of the precipitate is low 

 and the magnesium high. Magnesium pyrophosphate must be heated for at 

 least i hour. Magnesium ammonium phosphate loses water and ammonia at 

 100° C. 



Detection of arsenic acid in the presence of phosphoric acid, G. Madeena 

 (Atti R. Accad. Lincei, Rend. CI. Sci. Fis., Mat. e Nat., 5. ser., 19 (1910), II, 

 No. 2, pp. 68, 69; abs. in Chem. ZentbL, 1910, II, No. 12, p. 913).— To a slightly 

 acid boiling solution of the alkali salts of both of the above-named acids add 

 from 10 to 15 cc. of a concentrated solution of ammonium nitrate and about 

 1 gm. of solid ammonium molybdate. After the ammonium molybdate is dis- 

 solved, boil for another Ih minutes. The formation of a white precipitate indi- 

 cates the presence of arsenic acid. Where much arsenic acid is present the 

 precipitate is thrown down at once, but with smaller amounts boiling for a 

 longer period is necessary. 



Investigations on the estimation of inorganic phosphorus in animal tis- 

 sues, A. C. Whittier (Jour. Indus, and Engin. Chem., 3 (1911), No. .'/, pp. 

 248-250). — Considerable difficulty was experienced in this work in obtaining 

 concordant results with the barium method (E. S. R., 17, p. 635), owing to the 

 fact that the solution as obtained was, in most instances, cloudy. Where the 

 solutions were clear, or the extracts were first coagulated, the results were 

 fairly concordant with those obtained by the magnesium method (E. S. R.. 23, 

 p. 303). In most instances, however, the results for ox'ganic phosphorus were 

 high. This difference in result the author does not believe is due to a hydrolysis 

 of the organic into the inorganic state, but rather to the fact that a better 

 ])recipitation takes place when the solutions are clear. Enzyms and the 

 bacteria, according to the author, " seem to exert more of a hydrolyzing influence 

 on organic phosphorus compounds of animal tissues than does boiling." The 

 heating of flesh extracts has a tendency to check the activities of such 

 organisms. 



