RECENT WORK I\ AGRICliLTlRAL SCIENCE. 



CHEMISTRY. 



The qualitative detection of mineral phosphates in Thomas 

 slag, N. vox LoKENZ (ZAsy-///', Landw. Versuohir. Ocsfe/'r.,J {1000), j). 

 68^; ahs. hi Chew. Ztg., % {1900), M. 96, Repert., X). 355).— K filter 

 paper about 5 cm. in diameter is moistened with about 1 cc. of 5 per 

 cent soda sohition and spread over the convex side of a large watch 

 glass which is suspended for about 5 minutes ov^er a beaker in which 

 10 gui. of the Thomas slag has been stirred up with 'M) cc. of concen- 

 trated sulphuric acid. The filter paper is then washed ofi' into a 

 beaker with 2 to 8 cc. of water and the solution tested for liuorin 

 with calcium chlorid in presence of acetic acid. The presence of 

 fiuorin is taken to indicate the presence of mineral phosphates. 



Estimation of alkali carbonates in the presence of bicarbon- 

 ates, F. K. Cameron {Aine,: Cher,,. Jour., 'M {1900), No. 6, pj>. 

 4.71-486). — Titration in the cold with a solution of acid potassium 

 sulphate, using phenolphthalein as an indicator, is claimed to give 

 satisfactory results in the examination of alkali soils. The reaction 

 which occurs is as follows: Na,CO,+ HKSO,= HNaC03+ NaKSO,. 

 The reaction products are neutral to ordinary indicators. Chlorin 

 may be determined in the solution after the determination of the car- 

 bonate by adding a slight excess of the sulphate and titrating with 

 silver nitrate solution, using potassium chromate as indicator. The 

 method also seems to l)e adapted to the determination of silicates, 

 borates, phosphates, and the salts of weak acids in general. 



Methods of determining proteid nitrogen in vegetable materials, 

 G. S. Fkaps and J. A. Bizzell {Nortli Carolina Sta. BaJ. ll'J^., pp. 

 95-10Ji).—T\^Q, authors report a study of phospho-tungstic acid and 

 bromin as precipitants for the proteids of vegetable materials. The 

 phospho-tungstic acid method as proposed by Mallet and the bromin 

 method as proposed by Wiley for animal materials (E. S. R., 10, p. 819) 

 were modified and compared in a series of determinations with the 

 copper hydroxid method as proposed by Stutzer and adopted by the 

 Association of OiEcial Agricultural Chemists. A variety of vegetable 

 and animal materials were used in the comparative determinations. 

 Tests were made of the efi'ect of temperature and of the quantity of 



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