1919] AGKICULTURAL CHEMISTRY — AGROTECHNY. 803 



These constants ure compared wiLli reportcMl values for California and 

 Italian olive oil. 



Oil of fenugreek, H. E. "Wunschendorff {Jour. Pharm. ct Chim., 7. ser., 19 

 (1919), No. 11, pp. 397, 398).— The physical properties of the oil obtained from 

 fenugreek seeds are described, and a table is given of its analytical con- 

 stants. The oil is of a golden yellow color and disagreeable taste and odor. 

 It belongs to the drying oils, solidifying very rapidly when exposed to the 

 air. The analytical constants are as follows: Specific gravity at 15° C. 0.9471, 

 index of refraction at 22° 1.4774, saponification number 189.5, iodin number 

 137.8, and acidity 3.2 per cent. 



The estimation of chlorate and perchlorate in saltpeter, A. Wogeinz and J. 

 KuBER {Chem. Ztg., 43 (1919), No. 5-6, pp. 21. 22; aba. in CJiem. Abs., 13 (1919), 

 No. llf, p. 1571). — This is a critical discussion of various methods of determin- 

 ing chlorates and perchlorates in potassium and sodium nitrate. 



Comparative determination of humus by the Grandeau and Hilgard meth- 

 ods, J. Mendes db Godoy (Escola Agr. " Luiz de Qiieroz," Firacicnha. Brazil, 

 Ser. Chim. Agr. Bol. 2 (1919), pp. 12. fig. 1). — Experiments with 13 different soils 

 to compare the methods of Grandeau and Hilgard for determining humus con- 

 tent are reported. 



In all cases a greater humus content was indicated by the Grandeau method 

 than by the Hilgard method, and in most cases the Grandeau method indicated 

 more humus in the subsoil than in the soil, while the opposite was the case with 

 the Hilgard method. It is concluded that the Hilgard method is the better. 



Direct determination of nonamino nitrogen in the products of protein 

 hydrolysis, A. Hiller and D. D. Van Slyke (Jour. Biol. Vhcm., 39 (1919), No. 

 3, pp. 479-488). — A modification of the Van Slyke method of analyzing proteins 

 (E. S. R., 34, p. 505) is described, in which the nonamino nitrogen instead of 

 bei^g determined indirectly is determined directly in the nonamino acid fraction 

 of the products of protein" hydrolysis. 



The procedure is exactly the same as that used in the former method for 

 protein analysis until the hexone bases have been separated from the remaining 

 amino acids. After the removal of the phosphotungstic acid from the filtrate 

 with amyl alcohol and ether, the primary amino nitrogen is removed by warm- 

 ing with sodium nitrite and hydrochloric acid, the excess nitrous acid removed 

 by reduction to ammonia with a zinc-copper couple by Scales' method (E. S. R., 

 36, p. 504), and the residual nonamino nitrogen determined by the ordinary 

 Kjeldahl method. 



The results of this method in analyses of casein and gelatin are said to agree 

 closely with the results obtained indirectly. This indicates that " the original 

 method, although indirect, contains no inherent errors, and that when due 

 precautions in regard to calibrated apparatus and standardized solutions are 

 observed, results of practically the same degree of accuracy can be obtained by 

 the original, somewhat simpler indirect method, as by the present direct one." 



Determination of gluten, Marchadier and Goujon (Ann. Chim. Analyt., 2. 

 ser., 1 (1919), No. 8, pp. 243-246; also in Jour. Pharm. ct Chim., 7. sen, 19 (1919), 

 No. 12, pp. 425-434) ■ — A method for the determination of gluten in flour is de- 

 scribed, which consists essentially in centrifuging 1 gm. of flour with 10 cc. 

 of pure acetic acid for about five minutes at 1,500 revolutions per minute, 

 pouring ofi: the supernatant liquid, and repeating the process twice. The com- 

 bined solutions of gluten in acetic acid are evaporated on a water bath to dry- 

 ness and heated in an oven at 100° C. for an hour, the resulting residue repre- 

 senting the dry gluten. 



Determination of citric acid in mixtures and compounds, T. C. N. Broek- 

 sMiT (Phann. Weekbl, 56 (1919), No. 31, pp. 1047-1052) .—The method consists 



