CHEMISTRY. 613 



tlie lead acetate and amyl aleoliol methods now in use. He adds 2 

 ceil ti grams of the mercuric oxid (Chazeueuve recommeuds 1.0 to 1.5 

 ceutigiains) to 10 cc. of wine, shakes viiiorously in a test tube for 1 

 minute, and litters repeatedly through the same iilter until clear. A 

 colorless or slightly yellow filtrate indicates the absence of coal-tar 

 derivatives, while their presence is shown by a red color, — w. d. 



BIGELOW. 



Determination of extract in wine, T. Omets {CJtcm. Zff/.,18 {1894), 

 JSo. 85, p. lOiiO). — The author considers that the various results obtained 

 by different analysts in the deternunation of extract are largely due 

 to the volatilization of glycerin. In the determination of extract he 

 evaporates 50 cc. of the wine in a platinum dish on a gently boiling 

 water bath until the contents of the dish begin to show a sirup-like 

 consistence. Carrying the evaporation too far causes a loss of glycerin. 

 The dish is then dried 2J hours in a comiwrtment of a water-drying 

 oven, only one dish being placed in a compartment. The compart- 

 ments are about 6 cm. high and 10 cm. square, are entirely separated 

 from each other, and each is surrounded on all sides by steam. The 

 author does not obtain comparative results with duplicates placed on 

 different shelves of a larger drying bath, though the temi)erature ou 

 both shelves is the same. [This may be due to the fact that the water 

 is in contact with the bottom of the drying bath, and dishes resting 

 directly on it will be kei)t at a slightly higher temperature than those 

 on a shelf passing through the center of the bath]. — w. D. J5ICtEL0W. 



Determination of tannin in fruit "wines, E. Hotter {Chem. Ztf/., 

 18 [1894), No. 68, pp. 1305-1306). — Owing to the constant decrease iu 

 the percentage of tannin (due to the presence of albuminoids) the author 

 considers it essential that the tannin be estimated in a fresh sample. 

 One hundred cubic centimeters of the fruit wine under examination 

 and 50 cc. of strong alcohol are placed in a 150 cc. flask, mixed, and the 

 flask filled to the mark with water. This is then filtered from the 

 precipitated albuminoids, and measured portions treated in the usual 

 way before and after treatment with boneblack. — w. D. bigelow. 



The determination of glycerin in -wine, P. Kulisch {Forsch. il. Nah- 

 rungsmtl., 1 {1894), p. 280; abs. in Chem. Ztg., 18 {1894), No. 84, Bcpert, 

 p. 248). — The autlior calls attention to several sources of error in the 

 estimation of glycerin. First, some glycerin is volatilized when the 

 alcohol-glycerin solution is evaporated too rapidly. He states that 

 enough lime must be added to combine with all of the sugar present, 

 as otherwise the glycerin will dissolve an appreciable amount of the 

 sugar. He finds 1.5 gm. of calcium hydrate to be sufficient for each 

 2 gm. of extract in wines containing less than 3 per cent of sugar. 

 The author considers that 25 cc. of the alcohol-ether mixture is not 

 sufficient in all cases, and recommends that a larger quantity be 

 employed. — w. d. bigelow. 



