AGEICULTURAL CHEMISTRY — AGBOTECHNY. 711 



these smaller quantities of fluorids approximate estimations may be effected if 

 the titrations are carried out in the presence of proportionately small amounts 

 of sodium chlorid." 



Carbon dioxid apparatus III. — Another special apparatus for the estima- 

 tion of very minute quantities of carbon dioxid, S. Tashiro {Jour. Biol. 

 Chem., 16 (1914), No. 4, pp. 485-494, figs. 2).— Althougli the apparatus previ- 

 ously mentioned (B. S. R., 28, p. 410) is deemed satisfactory for almost all 

 micrometabolic problems, it is sometimes inconvenient for the complete deter- 

 mination of the carbon dioxid production of a single tissue, the metabolic rate 

 of which is constantly changing and the available amount of which is not very 

 great. The device described in this paper was constructed for satisfying this 

 need. 



The estimation of nitrogen in Norwegian saltpeter, N. Busvold {Chem. 

 Ztg., S8 {1914), No. 75, pp. 799, 800, fig. 1; ahs. in Ztschr. Angeic. Chem., 27 

 (1914), ^^o. 75, Referatenteil, p. 545).— It has been found that analyses of 

 Norwegian saltpeter made with the ordinary Kjeldahl apparatus give low results 

 for nitrogen, and a study was therefore made of various other methods. The 

 method finally decided upon was the one utilizing the principle of converting 

 nitrate into ammonia reported by Treadwell and Wegelin.<» 



Determination of nitrogen in mixtures of calcium nitrate and cyanamid, 

 A. Stutzer (Chem. Ztg., 38 {1914), No. 56, p. 597; abs. in Jour. Soc. Chem. 

 Indus., 33 {1914), A^o. 11, p. 606).— In the method nitrite and nitrate are de- 

 termined first by Schlosing's method (reaction with ferrous chlorid). Then an 

 aliquot made free from nitrate is treated by Kjeldahl's method. " By heating 1 

 gm, with 5 gm. of dry ferrous chlorid and 25 cc. of concentrated hydrochloric 

 acid, under slight pressure (in a flask fitted with a Bunsen valve), the nitrate 

 may be completely eliminated on the water bath in half an hour. In preparing 

 a mixture of calcium nitrate and cyanamid for use as a fertilizer, loss of nitro- 

 gen is liable to occur if the temperature be raised above 60° C." 



The vegetation test as a basis for fertilizer analysis, Mitscheblich 

 {Landtv. Vers. Stat., 85 {1914), No. 3-5, pp. 202-218, figs. 2).— A discussion of 

 the methods for making vegetation tests and their interpretation on a mathe- 

 matical basis. 



The estimation of silicic acid in natural waters, L. W. Winklek {Ztschr. 

 Angeic. Chem., ^7 {1914), No. 66-69, Aufsatzteil, pp. 511, 512).— The method is 

 based on the yellow color produced when ammonium molybdate is added to a 

 water containing silicic acid and then acidified with hydrochloric acid. The 

 intensity of the color is proportional to the amount of silicic acid present. A 

 solution of potassium dichromate is used as the colorimetric standard. 



Note on a new apparatus for use with the Winkler method for dissolved 

 oxygen in water, H. L. Shoub {Pub. Health Surv. U. S., Hyg. Lab. Bui. 96 

 {1914), pp. 83-85, fig. 1). — A description with illustrations of the apparatus. 



Nitrogen -protein table, R. S. Callaway {Jour. Indus, and Engin. Chetn., 

 7 {1915), No. 2, p. 161). — A table for chemists making analyses of feeding stuffs 

 using the factors 5.7 and 6.25. 



Apparatus for the determination of fat by the Roese-Gottlieb method, 

 W. Bbinsmaid {Jour. Indus, and Engin. Chem., 6 {1914), No. 4, pp. 324, S25, 

 figs. 4). — ^A modified Roese-Gottlieb tube differing somewhat from the Patrick 

 modification of the apparatus. 



The unsaponifi.able constituents of natural and hardened fats, J. 

 Mabcusson and G. Meyeeheim {Ztschr. Angew. Chem., 27 {1914), No. '28, 



" Kritische Priifung der wichtigsten Metliodeii zur Bestimmung der Salpetersaure. 

 Zurich, 1907, pp. 135. 



