abstracts: chemistry 299 



CHEMISTRY. — The determination of celhdose in rubber goods. S. W. 

 Epstein and R. L. Moore. Bur. vStandards Tech. Paper 154. 

 Pp. 16. 1920. 



After a discussion of the value of a procedure for determining eel 

 lulose in rubber goods and consideration of the literature on the subject, 

 the proposed method is discussed. 



Method. — Sample is digested with cresol at 160-185° C. for 4 hours 

 to dissolve the rubber. Filtration is facilitated by addition of 200 cc. 

 of petroleum ether. After washing with benzol, 10 per cent solution 

 of hydrochloric acid, water and acetone, the material is dried and 

 weighed. It is then acetylated by heating for 30 minutes at 75° C. 

 in a mixture of 15 cc. of acetic anhydride and 0.5 cc. of concentrated 

 sulphuric acid. This is filtered on a weighed Gooch, washed with 

 90 per cent acetic acid and then with acetone and dried and weighed. 

 Loss in weight is recorded as cellulose. S. W. E. 



ANALYTICAL CHEMISTRY.— T/^e analysis of silicate and carbonate 

 rocks. W. F. HillEbrand. U. S. Geol. Survey Bull. 700. Pp. 



285, figs. 23. 1919. 



This book, which is the fourth edition of Dr. Hillebrand's treatise, 

 sets forth the modern methods of procedure to be followed or the pre- 

 cautions to be observed in rock analysis. The author advocates that 

 rock analyses should be made as complete as possible, and not stop 

 with determinations of silica, alumina, the oxides of iron, lime, magnesia, 

 the alkalies and water; and suggests that, whenever possible, a thorough 

 microscopic examination of the rock in thin section should precede the 

 chemical analysis. Useful appliances and apparatus are described and 

 illustrated. R. W. StonE. 



CHEMISTRY. — Estimation of nitrates and nitrites in battery acid. 

 L. B. Sefton. Bur. Standards Tech. Paper 149. Pp. 38. 1920. 



From among the various methods suggested for the estimation of 

 nitrates and nitrites in small amounts, and admitting of a sulphuric 

 acid medium, three methods for the determination of nitrates — the 

 Diphenylamine, the "Hydrostrychnique," and the Brucine — and three 

 for the determination of nitrites — the Iodide, the Indol and the Di- 

 methylaniline — were selected and studied with reference to their use 

 in testing battery acid. 



