1919] AGRICULTURAL CHEMISTRY AGROTEGHNY. 311 



A milling of tin- unknown lower than thai of the standard indicates a deficiency 

 in, and higher than tin- standard an excess of, methyl alcohoL 



The reaction called u l'eclair bleu " and its application to the control of 

 vinegars and wines, [J.] JeaitvbAtre {Mitt. Lebensm. Dnterauch. a. Hyp., 

 Bchwelz. GandMsamt., ? (1916), No. 6, pp. SS8 646, figs. 4).— The author recalls 

 the report of Landolt, 1 who found that If to a mixture of equal volumes of 

 sulphurous and bydriodir acids containing a certain amount of Starch solu- 

 tion various adds are added, the liberation of Iodic Is accelerated under tbe 



same conditions of temperature and concentration, in direct proportion with 

 the constant of dissociation of the acid used. The sudden appearance of the 

 blue color led to the name of " l'eclair hleii," or blue Hash. 



In the present application of the test to the control of vinegars and wines, 

 the reagents employed are - per cent solutions of sodium lodate and of sodium 

 sulphite and a 0.5 per cent solution of starch. At the time of the test, 10 CC, 

 each of the lodate and sulphite solutions and 5 CC. of the starch solution are 

 made up to 1(H) cc. with distilled water. The test consists of mixing rapidly 

 lo cc. of the acid liquid and 10 cc. of the reagent and noting the time of 

 appearance of the hlue color. 



With pure N/10 solutions of different acids, the blue color appeared as fol- 

 lows: Acetic acid in 438 seconds, succinic 320, malic .">■_'. citric 45, and tartaric 

 lit;; with N Hi solutions of oxalic and of mineral acids the reaction was instan- 

 taneous. 



The author discusses the Interpretation of results with mixtures of acids, 

 the effect of different factors on the results, and the application of the method 

 to the analysis of Vinegars and wines. While the reaction does not permit of 

 an exact determination of the degrees of acidity, it Is considered to be of value 

 not only for the control of acid beverages, but also for determining the purity 

 of tbe greater part of organic acids and their acid salts. 



New methods for the analysis of butter, P. Ebctjusse and H. Dackwkiikk 

 [Ann. Chim. Analyt., 23 (1918), No. 11. pp. 225-231,; abs. in .lour. Hoc. Chem. 

 Indus., SI (1918), No. 24, p. 7S0. t ) .— The customary determinations in the ex- 

 amination of butter are described and criticized. As substitute determinations, 

 there are proposed the index of saponification, the silver index, and tbe 

 magnesium index, these being respectively tbe number of milligram molecules 

 contained in i gm. of fat, of fatty acids, butyric add, and caprolc, caprylic, 

 and capric acids. From these values can be calculated the true Reichert-Meissl, 

 Polenske, and Hehner numbers. 



The saponification index is obtained in tbe usual manner of determining the 

 Saponification number. The silver index Is obtained by precipitating a known 

 amount of neutral soap by giver nitrate, which precipitates everything but 

 butyrate. The index is then determined by comparison with the saponification 

 index. The magnesium index is obtained by precipitating a new amount of 



neutral soap by magnesium sulphate, which leaves in the filtrate only those 



acids with fewer than 12 carbon atoms (with tbe exception of butyric acid). 

 These are then precipitated with N silver nitrate. 



The methods, which are described in detail, are said to lie "more rapid and 

 accurate than the customary determinations, and to oe callable of application 

 to the analysis of all kinds of fats and their derivatives, such as soaps. 



A rapid and accurate method for butter analysis, suitable for factory con- 

 trol work, E. F. Koiimw (Jour. Indus, and Enijin. Chem., 11 (1919). No. 1. p. 

 36). — A method of butter analysis is described in which the fat and salt are 

 determined in connection with the moisture test as follows: 



»Ber. Deut. Chem. Gesell., 19 USfcC), pp. 1317-1303. 



