714 EXPERIMENT STATION RECORD. [Tol. 87 



ommended eliminates the use of large amounts of acid ordinarily used for oxi- 

 dation. 



lodometric determination of chlorin in chlorids, G. Tobossian (Jour. Indus, 

 and Engin. Chem., 9 (1917), No. 8, pp. 151, 752, fig. 1). — In the proposed method 

 the sample is mixed with finely powdered manganese dioxid and treated with 

 sulphuric acid (1:1 by volume) in a distilling flask. The chlorin produced by 

 the interaction of the MnOj and liberated hydrochloric acid is distilled into 

 potassium iodid solution and the liberated iodin titrated as usual with tenth- 

 normal sodium thiosulphate. 



Comparative analytical data with the standard silver nitrate procedure indi- 

 cate the accuracy of the proposed method. 



A new test for chlorin in drinking water and its application for the esti- 

 mation of the chlorin present, R. L. M. Wallis {Indian Jour. Med. Research, 

 4 (1917), No. 4, pp. 7D7-799). — A colorimetric procedure which depends on the 

 production of a yellow color in a solution of benzidine or tolidin by chlorin Is 

 described as follows: 



To 100 cc. of the sample to be tested In a Nessler tube 1 cc. of a 0.1 per cent 

 solution of benzidine in 10 per cent hydrochloric acid Is added. The solution 

 first becomes blue, but on stirring the blue color rapidly changes to a bright 

 yellow. The mixture is allowed to stand for exactly five minutes and then 

 compared with standards prepared under similar conditions. 



The production of the color is not affected by the salts present In drinking 

 water or other chemical reagents added for purposes of sterilization. The 

 delicacy of the test is indicated by its being able to detect 0.005 parts per 

 million of chlorin in drinking water. 



For effective chemical sterilization of water 1 part of chlorin In 500,000 

 parts of water is considercnl necessary. 



The chemical examination of potable waters. — I, Determination of organic 

 matter, I. M. KoLTnoFF {Pharm. Weckbl., 54 {1017). No. 22, pp. 5 47 -5 5. 'i).— The 

 addition of 5 cc. of four-normal sulphuric acid and 25 cc. of -r^normal po- 

 tassium permanganate to 100 cc. of the water sample and the determination of 

 the excess potassium permanganate lodometrically after 24 hours is considered 

 to be the best procedure for the determination of organic matter in potable 

 waters and to yield satisfactory results. 



A new method for the determination of aldehyde sugars, .T. Boi'gault 

 {Compt. Rend. Acad. Sci. [Paris], 164 (1917), No. 26, pp. 1008-1011).— K new 

 method for the determination of aldehyde sugars which depends on the oxida- 

 tion of the aldehyde to the corresponding monobasic acid with Iodin in the 

 presence of sodium carbonate Is note<l. The presence of ketonlc sugars does 

 not affect the result. In mixtures containing sucrose and other nonreducing 

 sugars the accuracy of the procedure depends on the relative proportion of the 

 sugars present. With increasing amounts of nonreducing sugars the necessary 

 correction increases, and .so slightly diminishes the accuracy of the results. The 

 principal disadvantage of the method Indicated Is the interfering action of 

 other organic substances that are likely to be present with the aldehyde sugars. 



The details of the reaction and of the method are reserved for a future com- 

 munication. 



The acid content of fruits, W. D. Bigelow and P. B. Dunbar (Jour. Indus, 

 and Engin. Chcm.. 9 (1917), No. 8, pp. 762-767).— The following results ob- 

 tained in an examination of the acids found in various fruits are reported: 

 Apple, cherry, and plum, malic only ; banana, peach, persimmon, probably malic 

 only; cantaloup, malic none, probably all citric; cranberry, citric probably 

 predominates, malic also present ; currant, citric probably predominates, malic 

 sometimes present; gooseberry, malic and citric; pear, malic only in some 



