416 EXPEEIMENT STATION EECORD. [Vol. S5 



The recovery of copper sulphate from the filtrates in sugar determinations 

 by using Fehling's solution, Krumhaab {Chem. Ztg., 40 {1916), No. 2^, p. 

 174). — The following procedure is recommended: 



The clear filtrate is sufficiently heated on the water bath and enough sugar 

 solution added to reduce the copper. The precipitated cuprous oxid is washed 

 several times by decantation, filtered on a porcelain filter, and washed free from 

 alkali. It is then treated in a beaker with 200 cc. of concentrated hydrochloric 

 acid, heated on the water bath, and the copper oxidized by the repeated addi- 

 tions of small amounts of hydrogen peroxid. The cupric chlorid solution thus 

 formed is evaporated nearly to dryness, an excess of dilute sulphuric acid 

 added, and the hydrochloric acid expelled by repeated evaporations to dryness 

 and re-solution in water. Finally, the concentrated solution of copper sulphate 

 is filtered and poured into about three volumes of 96 per cent alcohol. A pure, 

 fine crystalline salt is obtained which is filtered on a Buchner funnel and 

 washed with alcohol. 



The estimation of reducing sugars by Kendall's solution and the con- 

 struction of a table indicating the reducing power of levulose, Edith G. Wil- 

 son and W. 11. G. Atkins {Biochem. Jour., 10 (1916), No. 1, pp. 137-141). — 

 The authors have found Kendall's procedure, previously noted (E. S. R., 28, 

 p. Ill), for the determination of reducing sugars to be very satisfactory. The 

 copper oxid is not, however, determined by the iodimetric method, as origi- 

 nally recommended, but by conversion of the cuprous into cupric oxid. The 

 presence of citric acid interferes seriously with the accuracy of the method. 



A table for converting milligrams of cupric oxid to milligrams of levulose 

 is included. 



The analysis of maple products. — VIII. The application of the conduc- 

 tivity and volumetric lead subacetate tests to maple sugar, J. F. Snell and 

 G. J. Van Zokeen (Jour. Indus, and Engin. Chem,., 8 (1916), No. 5, pp. 421, 

 422). — It has been demonstrated that "pure maple sugars converted into sirups 

 give conductivity values and volumetric lead numbers within the limits found 

 in genuine maple sirups." 



See also a previous note (E. S. R., 35, p. 206). 



Solubility data for various salts of lauric, myristic, palmitic, and stearic 

 acids, C. A. Jacobson and A. Holmes (Jour. Biol. Chem., 25 (1916), No. 1, 

 pp. 29-53). — Tabular data as to the solubility of the lithium, magnesium, 

 beryllium, barium, lead, and silver salts of lauric, myristic, palmitic, and 

 stearic acids are submitted in detail. The data include solubility figures in 

 two or more of the following solvents: Water, ethyl and methyl alcohol, ethyl 

 ether, benzene, ethyl acetate, methyl acetate, amyl alcohol, amyl acetate, chlo- 

 roform, and acetone, at room temperature, 25, 35, and 50° C. wherever the 

 boiling point of the solvent permitted. The preparation of the salts, together 

 with the methods used for determining the solubility, is also described. 



The data indicate that the solubility of all the salts of the four fatty acids 

 in the various solvents tried is very slight. Considerable differences are found, 

 however, not only among the several salts in the same solvent but also for the 

 same salt in the different solvents. Methyl alcohol was found to be the best 

 general solvent for these salts. 



These data were obtained in connection with work on the constituents of 

 alfalfa-.seed oil, previously noted (E. S. R., 34, p. 710). 



The separation of lauric and myristic acids from each other and from 

 mixtures of other fatty acids, C. A. .Jacobson and A. Holmes (Jour. Biol. 

 Chem., 25 (1916), No. 1, pp. 55-61). —The authors describe a method for the 

 separation of lauric acid when present in a mixture of myristic, palmitic, and 

 stearic acids, and also a method for the separation of myristic acid from a 



