804 EXPERIMENT STATION" RECORD. 



ning with permanganate. Gunning, Kjeldahl-Gunning, Gunning with copper 

 sulphate, and Kjeldahl with copper sulphate, reported by 48 cooperating labora- 

 tories. 



The agreement obtained between the results of moisture determinations was 

 found to be much inferior to that obtained in the determination of nitrogen. 



Analysis of calcium cyanamid, H. Kappen (Chejn. Ztg., 35 (1911), No. 

 104, PP- 950-952; ahs. m Analyst, 36 (1911), No. 42S, pp. 560, 561).— ^o differ- 

 ence in the results was noted in determining nitrogen by the ordinary Kjeldahl 

 method as compared with the results obtained after adding zinc dust and sali- 

 cylic acid or sodium thiosulphate and salicylic acid. Adding water to the ma- 

 terial before adding the sulphuric acid was also found to have no effect upon 

 the results. The author, therefore, concludes that commercial calcium cyanamid 

 " yields all its nitrogen as ammonia when 0.5 gm. is digested with 30 cc. sul- 

 phuric acid." 



For estimating cyanamid nitrogen when distinguishing this from total nitro- 

 gen the author employs a modified Perotti method (E. S. R., 21, p. 419). 



See also the work of Dinslage (E. S. R., 26, p. 606), Stutzer (E. S. R., 25, p. 

 805), and Monnier (E. S. R., 26, p. 109). 



Detection and determination of cyanamid in the presence of other fertiliz- 

 ing materials, L. Vuaflart (Ann. Falsif., 4 (1911), No. 32, pp. 321-324).— 

 The presence of calcium cyanamid in a mixture containing other fertilizers can 

 be detected by its odor, alkaline reaction, the large amount of calcium present, 

 the black residue which is left after treating the sample with water, and the 

 yellow precipitate obtained with silver nitrate which is insoluble in ammonium 

 hydroxid but soluble in nitric acid. An impurity often present in the latter is a 

 black acetylene silver insoluble in nitric acid. If organic fertilizers are present 

 in the mixture these can be detected by dissolving the cyanamid in hydrochloric 

 acid, when the organic matter will remain behind as a black residue. Sulphuric 

 acid added to such fertilizers will yield a brown solution. 



For the determination of total nitrogen in such materials the Kjeldahl method 

 can be employed, while the cyanamid and dicyanamid present as such may be 

 estimated with Brioux's modification of Caro's method (E. S. R., 24, p. 623). 

 The method does not furnish accurate results when other fertilizing materials, 

 such as dried blood, are present. 



International conference on food analysis (Analyst, 36 (1911), No. 428, 

 pp. 536r-539). — The I'ecommendations of the international conference at Paris, 

 June 27, 1910, together with the rules proposed for the unification of the ex- 

 pression of analytical results, are presented in detail. 



Use of triketohydrindene hydrate for the detection of proteins and their 

 derivatives, E. Abderhalden and H. Schmidt (Hoppe-Scyler's Ztschr. Physiol. 

 Chem., 72 (1911), No. 1-2, pp. 31-43; ahs. in Analyst, 36. (1911), No. 421, p. 

 514). — ^Triketohydrindene hydrate was found to yield a blue coloration with 

 a-amino acids, polypeptids, peptones, and proteins. Exceptions to this are 

 prolin, hydroxy prol in, and pyrrolidon carboxylic acid. " For carrying out the 

 test a solution of 0.1 gm. of the reagent in 300 cc. of water is employed; 1 to 2 

 drops of this reagent are added to 1 cc. of the liquid to be tested, and the 

 mixture is heated to boiling. The liquid to be tested must have a neutral 

 reaction." 



The determination of starch, W. Geeifenhagen, J. Konig, and A. Scholl 

 (Biochem. Ztschr., 35 (1911), No. 3-4, pp. 194-216.). — The polarimetric methods 

 of Lintner (E. S. R., 20, p. 1008; 21, p. 611; 23, p. 708) and Ewers (E. S. R., 

 21, p. 108) can be employed for all varieties of starch. The specific rotation 

 for the different starches with the Lintner method is fairly uniform and is on 

 the average +202°. With the Ewers method it is very variable, but for corn, 



