AGRICULTUKAL CHEMISTRY^ AGEOTECHNY. 707 



pp. 445, -'f46). — The method is as follows: Place the substance in a distilling 

 flask which has a thistle tube attached, and add from 5 to 6 gm. of fine alumi- 

 num filings, 2 cc. of a saturated solution of mercuric chlorid, and from 150 to 

 200 cc. of water. Shake the mixture and connect the flask with the distilling 

 apparatus. A preliminary reaction takes place in whicli an abundance of 

 hydrogen is liberated. After the reaction is almost over add a few drops of 

 ])otassium hydroxid through the thistle tube, distill, and collect the distillate 

 in a titrated acid solution. 



The effect of chlorids on the estimation of nitrates in water, A, Sabatini 

 {Ann. Chim. Anahjt., IJ, {1909), No. 10, pp. 366, 367; 06s. in Jour. Chem. Sac. 

 [London], 96 {1909), No. 565, 11, p. 935).— The author is satisfied that Perrier 

 and Farcy's views on Grandval and Lajoux's method (E. S. R., 21, p. S) are 

 correct, and suggests the following jirocedure : Twenty gm. of silver oxid is 

 added to from 50 to 60 cc. of water, allowed to stand for 2 hours (shaking 

 several times in the .interval), and the liquid filtered free from chlorid. The 

 filtrate is then examined colorimetrically for nitrates. 



A new nitrite method, A. Sanin {Zliur. Russ. Fiz. Khim. Obshch., Chast 

 Khun., .',1 {1909), No. 6, pt. 1, pp. 791-795; abs. in Chcm. Zentbl., 1909, II. No. 

 20, p. 1773; Jour. Chem. Soc. [London], 96 {1909), No. 565, II, p. 935).— The 

 author criticises the existing methods and proposes a method which is based on 

 the following reaction: XaNO..+NH30.HCl=NaCl+N20+2H,0. In this method 

 the solution of hydroxylamiu-hydrochlorid is titrated for acid before and after 

 conversion by sodium hydrate. The difference between the two figures repre- 

 sents the amount of hydrochloric acid which was used for converting the nitrite. 

 The indicator eni]iloyed is phenolphthalein. 



Detection, of sodium sulphite in the presence of sodium sulphate and 

 sodium thiosulphate, F. E. Weston {Chem. News, 100 {1909), No. 2602, p. 

 176; abs. in Jour. Chem. Soc. [London], 96 {1909), No. 565, II, p. 93Jt).— To 

 5 cc. of a 5 per cent solution decinormal iodin solution is added. If this solu- 

 tion is decolorized sulphite or thiosulphate, or both are present. The addition 

 of iodin is continued until a faint coloration sets in, when the liquid is exam- 

 ined as to acidity. If acid, sulphite is probably present. 



To another 5 cc. of the original solution is added one-half the amount of 

 iodin required in the first test, when sulphur dioxid may be recognized by its 

 odor and also by its reduction of potassium bichromate. If sulphur dioxid is 

 evolved, sulphite is present. If no reduction of potassium bichromate takes 

 place and there is an absence of a green color, thiosulphate is indicated. The 

 sodium suli)hate can be detected with barium chlorid in the usual manner. 



Determining' the barium sulphate in presence of bodies that interfere, 

 M. J. Van't Kruijs {Chem. WeekbL, 6 {1909), No. 39, pp. 7.3.5-7.5S; abs. in Jour. 

 Chem. Soc. [London], 96 {1909), No. 565, II, p. 939).— The method has refer- 

 ence to the fact that where much calcium is present the resulting barium sul- 

 phate precipitate, although free from potassium, sodium, magnesium, iron, and 

 cobalt, will also contain an appreciable amount of calcium sulphate. By its use 

 the precipitated calcium is easily removed and perfectly ptire barium stilphate 

 is left. 



Detection of hydrogen fluorid in the presence of fluorid salts, W. Cron- 

 HEiM (Biochem. Ztsehr., 23 {1909), No. 1-2, pp. I'/S-l'io). — The author proposes 

 a method which is based on the fact that hydrofiuoric acid is soltible in ether 

 and alcohol, while the flouorid salts are not. 



The determination of benzoic and cinnamic acids in a mixture of the two 

 acids, A. W. K. De Jong {Rec. Trav. Chim. Pays-Bas et Belg., 28 {1909), No. 

 5-6, pp. S-i2-348).—A study of methods. 



