191G] AGEICULTUKAL CHEMISTRY AGROTECHNY. 417 



mixture of lauric, palmitic, and stearic acids. The methods are based on the 

 differences of solubility of the lithium and magnesium salts of the acids in 

 water and 50 per cent alcohol. 



Determination of tartaric acid, B. G. Habtmann, J. R. Eoff, and M. J. 

 Ingle {Jour. Indus, and Engin. Chem., 8 {1916), No. 5, pp. 422-425) .—Atter 

 preliminary experiments on the earlier methods for the determination of tar- 

 taric acid, the authors have modified the method of Halenke and Moslinger « 

 and describe their procedure as follows : 



For wines 100 cc. of the sample is neutralized with sodium hydroxid, and to 

 the neutralized wine is added a molecular equivalent in grams of powdered 

 tartaric acid corresponding to the amount of alkali required for neutraliza- 

 tion. After complete solution of the tartaric acid 2 cc. of glacial acetic acid 

 and 15 gm. potassium chlorid, together with 15 cc. of 95 per cent alcohol, are 

 added. The mixture is well stirred until precipitation has started and allowed 

 to stand overnight at a temperature not above 15° C. The solution is then 

 filtered through either a Gooch crucible prepared with filter paper pulp or a 

 Buchner funnel fitted with hardened filter paper, using gentle suction. The 

 precipitate is washed with three portions of 7 cc. each of a solution composed 

 of 100 cc. of water, 15 gm. of potassium chlorid, and 20 cc. of 95 per cent alcohol. 

 The precipitate and paper are transferred to the original beaker with 50 cc. of 

 hot water, brought to the boiling point, and immediately titrated with tenth- 

 normal sodium hydroxid, using phenolphthalein as indicator. A correction of 

 1.5 cc. added to the burette reading is necessary for solubility. This corrected 

 reading, multiplied by 0.015 and subtracting the amount of tartaric acid added, 

 is the total tartaric acid in the wine in terms of grams per 100 cc. Rochelle 

 salts may be used in place of tartaric acid. 



In artificial products containing free phosphoric acid and alcohol satisfactory 

 results with the method could not be obtained. The results were consistently 

 low, due to the formation of ester in the presence of the mineral acid. The 

 amount of ester was found to increase with the age of the sample. To obviate 

 this source of error 5 cc. of normal sodium hydroxid in excess of that required 

 for neutralization was added to 50 cc. of the solution under examination, heated 

 to boiling, and allowed to stand overnight. The determination was then carried 

 out in the usual manner. 



The analysis of nonalcoholic lemon and orang'e extracts, E. L. Redfebn 

 (Jour. Indus, and Engin. Chem., 8 {1916), No. 5, p. 4^21). — After some prelimi- 

 nary experiments the method described by Howard (E. S. R., 20, p. 113) was 

 found to be satisfactory and to yield concordant results. 



Some qualitative tests for gum arable and its quantitative determination, 

 C. E. Waters and J. B. Tuttle {Jour. Indus, and Engin. Chem., 8 {1916), No. 5, 

 pp. 413-416). — The qualitative tests commonly recommended for gum arable 

 are briefly reviewed. The most characteristic test was found to be the precipi- 

 tate with basic lead acetate. Mixtures of copper sulphate and sodium hydroxid 

 and of neutral ferric chlorid and alcohol were also found to be valuable as 

 confirmatory tests. 



After considerable preliminary experimentation a quantitative procedure 

 was devised and is described in detail. 



On the drying of sugar beets and other agricultural products and by- 

 products, A. Gkogeb {Arch. Chem. u. Mikros., 9 {1916), No. 1-2, pp. 1-47). — 

 This article discusses the subject in some detail and indicates the economic 

 importance of the drying of agricultural products. Some experimental and 

 statistical data are included. 



"Ztschr. Analyt. Chem., 34 (1895), No. 3, pp. 263-293. 



