19161 AGEICULTTJRAL OHEMISTEY — AGBOTECHNT. HI 



fat, preservatives, and starch, and considers the interpretation of analytical 

 results. The second pamphlet describes the various kinds of coffee, outlines the 

 methods for the determination of extraneous material, water, ash, water-soluble 

 extractives, caffein, artificial coloring matter, sugar and other carbohydrates, 

 fat, crude fiber, protein, borax, and arsenic-containing shellacs, and considers 

 the interpretation of the analytical results. 



The various coffee substitutes are described in the third pamphlet and the 

 prescribed requirements for such material outlined. Analytical methods for the 

 determination of sugar, mineral oils, and glycerin are described, as well as 

 some methods described in the pamphlet on coffee. The microscopical examina- 

 tion is also considered in some detail. 



The determination of volatile oil in liqueurs, L. Ron net (Ann. Falsif., 9 

 (1916), No. 87, pp. lIf-16). — The author outlines a method for the determination 

 of the essence in a liqueur, based on the determination of the iodin value, and 

 gives the procedure for calculating the amount of essence present from the 

 iodin value obtained. 



The determination of the volatile oils in liqueurs, G. F. Muttelet {Ann. 

 Falsif., 9 {1916), No. 87, pp. 17-22; Ann. Chim. Analyt., 21 {1916), No. 3, pp. 

 50-55). — A gravimetric method for the determination of volatile oils is described 

 in detail. 



Determination of the quantity of fat in cream, L. Lindet {Ann. Sci. Agron., 

 4. ser., 4 {1915), No. 1-6, pp. 1-6). — This material has been previously noted 

 from another source (E. S. R., 34, p. 714). 



Determination of stearic acid in butter fat, E. B. Holland, J. C. Reed, and 

 J. P. Buckley, Je. {V. S. Dept. Agr., Jour. Agr. Research, 6 {1916), No. 3, pp. 

 101-llS, figs. 2 ) . — A crystallization method devised at the Massachusetts Experi- 

 ment Station is outlined as follows : 



Five-tenths of a gram of melted insoluble acids is placed in an 8-oz. sterilizer 

 bottle and 150 cc. of an alcohol-stearic-acid solution (3 gm. to 1,000 cc), ac- 

 curately measured with a pipette at 30' C, added. The bottle is sealed with a 

 solid rubber stopper, shaken at a gradually increasing temperature until a 

 clear solution is obtained, placed immediately in a pocket of the ice tank, and 

 allowed to stand overnight. The following morning the solution is gently 

 agitated by inverting the bottle several times, and in the afternoon it is siphoned 

 off as thoroughly as possible by means of a small thistle tube and a perforated 

 rubber stopper, using suction. The residue is dissolved in ethyl ether, trans- 

 ferred to a tared 140 cc. wide-mouth Erlenmeyer flask, the ether carefully dis- 

 tilled off, the residue dried at 100°, and weighed. 



The construction of a constant-temperature tank, also devised by the authors 

 and used for the crystallization of the stearic acid, is described in detail. 



From the molecular weight determinations the crystalline precipitate ob- 

 tained from butter fat was shown to be pure stearic acid and not a mixture. 

 In studying the influence of various fatty acids on the precipitation of the 

 stearic acid, lauric, myristic, and oleic acids, even in relatively large amounts, 

 showed no appreciable effect. Palmitic acid, however, noticeably increased the 

 solubility and affected the crystalline structure of the precipitate. 



Analytical data obtained by the application of the proposed method to the 

 determination of the stearic acid in the insoluble acid in butter fat and beef 

 tallow are submitted in detail. The results indicate a higher percentage of 

 stearic acid in the insoluble acids of butter fat than has been reported by 

 earlier investigators. The concordant results obtained, however, and the close 

 agreement of the molecular weight determinations of the crystalline product 

 with the theoretical, indicate the identity and approximate purity of the stearic 

 acid. 



