RECENT WORK IX AGRICULTURAL SCIENCE. 



CHEMISTRY. 



New method for water analysis — Application of oleic acid as 

 an indicator in the quantitative determination of mineral matter, 

 E d'IIuart (2. Gongres Internal. Ghim. Appl, 1896, IV, pp. 289-293).— 

 In the method proposed oleic acid or oleiu and soda solution, used 

 separately, are substituted for the soap solution ordinarily employed in 

 testing the hardness of water. The method is as follows: To 50 cc. of 

 water add a few drops of pure olein, and then slowly run iu decinormai 

 soda solution until a lather appears on shaking, •which rapidly 

 disappears on standing. 



To another sample of 100 cc. of water add a few drops of hydro 

 chloric acid and boil until the carbon dioxid is completely expelled. 

 Cool, neutralize the acid carefully, evaporate to 50 cc, and test as 

 above directed. The result thus obtained, subtracted from the first 

 determination, gives the amount of soda equivalent to carbon dioxid in 

 the water. 



Boil a third sample of 50 cc. of water until the free carbon dioxid and 

 that of the bicarbonates is driven off. Cool, filter, make up the volume 

 to HO cc. with distilled water, and test as before. This furnishes data 

 for calculating the amount of carbon dioxid in the form of bicarbonate. 



To a fourth sample of 100 cc. of water add sufficient ammonium 

 oxylate to completely precipitate the calcium salts. Boil for half an 

 hour, Alter, cool, evaporate to 50 cc, and test as before to determine 

 the equivalent in caustic soda of the magnesia present in the water. 

 In comparative tests results obtained by this method agreed closely 

 with those obtained by gravimetric methods. 



Percentage of phosphoric acid in potable waters, C. Lepierre 

 (2. Congrh Internal. Chim. Appl, 1896, IV, pp. 267-272, dgms. 2). — This 

 is a study of the method proposed by Villiers and Borg. 1 As a result 

 of the study, tue following modification of the method is proposed: 

 Evaporate 1 liter of water to dryness in a porcelain, or better iu a plati- 

 num dish, with the addition of dilute nitric acid to separate the silica. 

 Take up in nitric acid and evaporate again to dryness to remove the 

 last traces of silica. Filter and wash until the filtrate amounts to 50 cc 

 and add 2 cc of molybdic solution, prepared by dissolving 150 gm. of 



1 Bui. Soc. Chiin. Paris, 9 (1893), p. 486 (E. S. R., 5, p. 519). 

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