308 . ■ EXPERIMENT STATION RECORD. 



mechanical method in the determination of phosphoric acid in natural 

 phosphates and phosphatic slag, II. I'kllet (Ann. Vlihn. Ainili/t.. 11 {lUHd), 

 'So. 9, pp. 331, 332; aha. in Chcin. Ccnthl.. 1006. II, No. 16. p. l.i8J,).— The author 

 briefly discusses the investigations of Guerry and Toussaint (E. S. It.. 18, p.lOT) 

 on this subject and describes the method which he employs to remove silicic 

 acid from solution, namely, moistening with hydrochloric acid, evaporating to 

 dryness, and taking up in hot hydrochloric acid. It is claimed that the removal 

 of silica is not necessary in the molybdic method, and that a precipitate of 

 phospho-ammonium molybdate of definite comi)osition can always be obtained. 



On the determination of phosphoric acid as magnesium pyrophosphate, 

 B. ScHMiTZ (Ztsclir. Aiialj/t. Cliciii., .',.') {1906). No. 8. pp. 312-.')22; abs. in Cliem. 

 Ccnthl., 1906, II, No. 10, p. 911).— The author precipitates the nearly neutral- 

 ized (with HCl) ammonia solution of the molybdic precipitate with add 

 (IK'l) magnesia mixture, finally malving tlie solution allvaline with ammonia. 



Should one titrate calcareous marl with sulphuric acid? Schulze {CJicni. 

 Ztff., 30 (1906). No. n, pp. 937, 938). — A series of comparative tests is reported 

 which showed that the use of sulphuric acid gives uniformly lower results than 

 hydrochloric acid, but the reason for this is not made clear. 



The determination of organic matter in waters by means of potassium 

 permanganate, A. Garcia (Ann. Chim. Analyt.. 11 (1906), No. 9, p. 3JiO). — 

 The author finds that the ammonia already present or set free from salts or 

 organic matter in water by alkaline permanganate is oxidized to nitrous or 

 nitric acid, which increases the amount of permanganate reciuired, and thus 

 alkaline permanganate gives higher results for organic matter than acid per- 

 manganate. 



The detection of humus substances in water, Klut (Phann. Zt;/., 51 

 (1906), pp. 777, 77,S'; ahs. In Vheiii. VcnthL, 1906, II, No. 13, p. 1081).— It is 

 stated that no typical reaction for this purpose exists. Various indirect tests 

 for color, odor, reaction, etc. are des('ril)ed. 



A new method for the quantitative estimation of pentosans, A. Jolles 

 (Zt-'^cJir. Analijt. Vlinii.. ','> U906), No. 3-',, pp. 196-20Jf) .—DeUxUea directions 

 are given for estimating furfurol, and data are reported showing the accuracy 

 of the method, which consists essentially in boiling the substance to be tested 

 with hydrochloric acid, distilling witli water vapor tlie furfurol formed, neutral- 

 izing with sodium-hydroxid solution, adding bisulphate solution, and titrating 

 with iodin. 



On uniform methods of analysis of cane factory products, H. Pellet 

 (Internat. Sugar JoHrV., 8 (1906), No. 94, PP- 506-.')ll). — Notes are given on the 

 steps which have been taken toward securing unification of the methods for 

 saccharine products in different countries. Analyses of cane molasses made by 

 three methods are given to illustrate the differences arising from the use of 

 different methods. Comments are made on the suggestions which have been 

 offered for the unification of methods and a resume of methods for the analysis 

 of molasses is given. 



An accurate commercial method for the analysis of sugar beets, D. L. 

 Davoll (Internat. Sugar Jour., 8 (1906), No. 9-'/, pp. 512-516, fig. 1). — ()li.jec- 

 tions to the method of hot-water digestion are overcome, according to the 

 author, by substituting a beaker for the flask, and finally completing the mass 

 to a certain weight, 209.2 gm.. instead of volume. By this method, which is 

 described, it is possible to make from fJOO to 700 analyses in one day. instead of 

 125 by the usual method. 



Report on the estimation of glucose by the volumetric method, A. Watt 

 (^Internat, Sugar Jour., 8 (1906), No. 94, PP- 502-506). — In determining glucose 



