CHEMISTRY. 545 



Tlie determination of iron in natural •waters, L. W. Winkler {Ztschr. Analyt. 

 Chem., 41 {1902), No. 9, pp. 550-552). — In the colorimetric method described ammo- 

 nium sulphid is used instead of the potassium ferrocyanid commonly employed. 



The determination of nitric acid in water by Noll's method, W. P. Kasch- 

 KADAMOV {Jour. Ochruii. Narod. Sdrav., 12 {1902) , p. 491; ah-i. in Chem. Zt/j., 26 {1902), 

 No. 94, Repert., p. 309). — The method is recommended. 



The volumetric determination of nitric acid in drinking- waters, O. Schma- 

 TOLLA {Apotli. Zhj., 17 {1!'02), pp. (197, '!9S; abs. in CJiein. ('eiifh/.., 1902, II, No. 18, 

 p. 1152). — A moditieatic . of the Marx method is recommended. 



The litmus-paper test for milk, li. D. Ricumoxd {Chem. News, S6 {1902), NoT^ 

 2238, pp. 192, 193). — The use of litmus jiaper for testing the aciitity of milk is con- 

 sidered very unsatisfactory. 



Methods for the estimation of the proteolytic compounds contained in 

 cheese and milk, L. I.. Van Slyke and E. B. Hart {Neiv York State Sta. Bid. 215, 

 pp. 81-102). — This gives in detail the methods outlined in Bulletin 203 of the station 

 (E. S. R., 13, p. 1087) and presented in full before the Association of Official Agri- 

 cultural Chemists (E. S. R., 14, p. 108). 



Concerning- the coagulable material in egg- white, L. Langstein {Beitr. Chem. 

 Phij.vol.u. r<it]uil. Ztschr. Biochem., 1 {1901), pp. 83-104; (d)S. in Ztschr. Untersuch. 

 Nulir. II. Genussiutl., 5 {1902), No. 14, p. 663). — Analytical data are reported and 

 discussed. 



Concerning the character of free fatty acids, E. A. Loscii {Inaug. Diss., Si. 

 Petersburg, 1902; rev. in Chem. Ztg., 26 {1902), No. 30, Repert., p. 105).— Under simi- 

 lar conditions butter and lard become more rancid, that is, form free fatty acids more 

 energetically, than sunfiower seed and almond oil. When butter becomes rancid, 

 strong-smelling products are produced. On the other hand, when the liquid fatty 

 oils become rancid such products are muc-h less abundant, but bodies having a sharp 

 and burning taste are produced. The increase in weight when fats become rancid is 

 very slight, being greatest in the experiments reported with sunflower-seed oil. 

 Generally speaking, the amount of volatile fatty acids is not large, while the amount 

 of free nonvolatile fatty acids is much increased. 



The estimation of starch in cereal grains, L. Lindet {Jour. PJtarm. et Cliim., 

 6. ser., 14 {1901), pp. 397-400; Ann. Chiin. Analyt., 7 {1902), pp. 41-43; abs. in Ztschr. 

 Untersuch. Nahr. u. Cienussmil., 5 {1902), No. I4, J)- 665). — In this method of estimat- 

 ing starch in cereals the i)roteid material is removed by digestion with pepsin and 

 hydrochloric acid and the starch which remains behind is treated with sulphuric 

 acid and soda and then measured l)y determining the glucose and dextrin in an 

 aliquot ]>ortion. 



Filtration in determination of crude fiber, R. W. Thatcher {Jour. Amer. 

 Chem. Soc, 24 {1902), No. 12,p)p. 1210, i^g'ii).— The author modifies the official method 

 by filtering through asbestos wool placed in a large funnel on a platinum coi>e. The 

 residue is washed into a platinum disli, the water evaporated, and the determination 

 completed as usual. This procedure is especially adapted to the glycerol-sulphuric 

 acid mixture used in the Konig method for fiber. 



The analysis of vanilla extract, A. L. Winton and M. Silverman {.lour. Amer. 

 Chem. So<:, 24 {1902), No. 11, pp. 1128-1135).— The authors give a modification of 

 the Hess and Prescott method for the determination of vanillin and coumarin 

 (E. S. R., 13, p. 420), which is designed to shorten the process without diminishing 

 the accuracy of the method. The modification consists in the use of a larger quan- 

 tity of 2 per cent ammonia and weighing the vanillin and coumarin immediately 

 after evaporation of the ether solutions. Analyses are also given of a number of 

 genuine and artificial vanilla extracts. 



Uniform methods for the examination and valuation of foods, condiments, 

 and commercial products in the German Empire ( Vereinharwigen zur einheit- 



