CHEMISTRY. 1023 



above mixture and shake for one-half hour in a rotary apparatus. 

 Filter at once, or allow to stand not longer than one hour before filtra- 

 tion, and proceed in the usual way. 



The determination of citrate-soluble phosphoric acid in Thomas 

 slag, O. Bottcher (Ghem. Ztg., 21 {1897), No. 95, pp. 993-995).— This is 

 a discussion of Wagner's paper above noted. The author claims pri- 

 ority in pointing - out the necessity for precipitation in the fresh extract 

 in order to avoid error due to the separation of silicic acid in the citrate 

 method of determining the phosphoric acid in the Wagner extract. 

 Experimental data are reported to support the claim that Wagner's 

 molybdic method is subject to the same errors due to separation of 

 silicic acid that have been found to affect the accuracy of the citrate 

 method under certain conditions and that the citrate method as modi- 

 fied by the author 1 is reliable when applied to the determination of 

 phosphoric acid in the Wagner extract. It is also claimed that, con- 

 trary to Wagner's statement (see above), an error may be introduced 

 by allowing the solution to stand for two hours after precipitation 

 before filtering. 



A new method of absolute measurement of gases, » >. Bleikh ( tier. Deut. Chem. 

 Gesell, 30 (1897), No. 19, pp. 3128-3131, figs. : i. 



On an organic phosphorus compound which yields inosite on decomposition, 

 E. Wintekstein ( Her. Dent. Chem. Gesell., 30 (1897), p. 2299; abs. in Bui. SocChim. 

 Taris,3.scr., SO (1S9S), No. i. p. 239). — Along -with the proteid substances extracted 

 from cereal grains with a 10 per cent sodium chlorid solution was obtained a com- 

 pound which contained 13 per cent of magnesium oxid and 42 per cent of phosphoric 

 acid (P _•() .-. ) and yielded inosite when treated with hydrochloric acid. The exact 

 chemical constitution of the compound was not determined. 



Chemical physiological investigation of sugar cane, F. A. F. C. Went (Jahrb. 

 Wiss. Hot. [Pringsheim], 31 (1898), No. 3, pp. 289-344, pi. 1). 



Inversion of sugar by neutral salts in the presence of glucose, II. ('. Prinsen- 

 Geekligs ( Meded. Proefstat. Suikerriet West Java, 31, pp. 1-1 .'). 



Action of neutral substances on glucose at high temperatures, II. C. Prinsen- 

 Geem.igs (Meded. Proefstat. Suikerriet West Jura. 31. pp. 12-1? ). 



Impure copper sulphate, 11. ('. Prinsen-Geerligs (Meded. Proefstat. Suikeii-iet 

 West Java, 31, pp. 17, IS). 



On the determination of oxygen dissolved in water, Albert-Levy and F. 

 Marboutin (Bui. Soc. rhim. Paris, 3. ser., 19 (1898), No. 4,pp. 149-151). 



Researches on the rapid determination of manganese in plants and humus soils 

 by a colorimetric method, P. Pichard (Compt. Bend. Acad. Sci. Paris, 126 ( 1898), No. 

 7, p. 530). — Incinerate, fuse with potassium or sodium carbonate, add a little dilute 

 nitric acid, place in a test tube with minium or lead bioxid, add a little water 

 and some pure nitric acid, and boil. The presence of manganese will he shown by 

 the rose color of the solution. 



A source of error in the Kjeldahl nitrogen determination, T. Freundlich ( Chem. 

 Ztg., 21 (1897), No. 77, p. 781). — Reports experiments which lead to the conclusion 

 that there is little danger of soda solution being carried over in the process of dis- 

 tillation if the tube fitted in the top of the flask be carried up sufficiently high before 

 it is bent. It is suggested that the neglect of this precaution or the long period of 

 distillation accounts for the errors noted by Sjollema. 2 



iChem. Ztg., 21 (1897), No. 78, p. 783 (E. S. R., 9, p. 520). 

 2 Chem. Ztg., 21 (1897), No. 74, p. 710 (E. S. R., 9, p. 418). 



