RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



The volumetric determination of potash, 11. H. Adie and T. B. 



Wood {Proe. Chem. Soc. London, 16^ pj). 17, 18; ah.s. In Chem. Centhl.^ 

 1900, /, Xo. 10, J)- -'''^S). — In the method proposed the potash is pre- 

 cipitated 1\Y means of col)alt nitrite, the precipitate usually having the 

 formula KgCo2(N02)io.3H20. The method is carried out as follows: 

 The potash solution is freed as far as possible from other leases, acidi- 

 fied with acetic acid, and an excess of sodium-colxdt nitrite is added. 

 After 24 hours the precipitate is collected on an asbestus filter, washed 

 with 10 per cent acetic acid, and final!}" with ^vater. The filter with 

 the precipitate is then boiled in dilute soda solution, filtered, and dilu- 

 ted to 100 cc. Twenty cubic centimeters of this solution is acidified 

 with dilute sulphuric acid and immediate])^ titrated with permang-anate 

 solution. It is reconnnended to add an excess of permang-anate and 

 titrate l)a('k with potassium iodid and thiosulphate solution. 



A new reagent for detecting and estimating nitrites in water, 

 H. Ekdmanx {Brr. I),„t. Chrin. GcxelL, .13 {1000), pp. iilO-;U5; 

 Ztschr. Angew. Chem., 1900, No. 2, p. 33; abs. in Analyst, 26 {1900), 

 Mar., pp. 81, 82; Bui. Soc. Ohiin. Paris, 3. ser., 2J^ {1900), No. 9, p. 

 JfiS). — The reagent used is amidonaphtholdisul phonic acid (1:8: -l-C)), 

 prepared by nitrating, reducing, and heating with sodium hydroxid 

 the naphthalene trisulphonic acid recently described by the author.^ 

 The method of procedure is as follows: Mix 60 cc. of the water with 

 5 cc. of a hydrochloric-acid solution of sodium sulphanilate (2 gni. per 

 liter), and after 10 minutes add 0.5 gm. of the amidonaphtholdisul- 

 phonic acid in the form of its acid alkali-metal salt. In presence of 

 nitrous acid a brilliant Bordeaux-red color appears, which attains its 

 maximiun intensity in 1 hour. To determine the amount of nitrites 

 present the color is compared with that produced l)y solution of 

 sodium iiitrit(> of known strengtii or with a colored pa])(M' scale. 



Methods for the detection of " process " or " renovated " but- 

 ter, W. H. Hkss and li. E. Doolittle {Jour. Aiiicr. Ohein. Soc, 

 22 {1900), No. 3, pp. 150-152).— The methods employed consist of tests 

 of the curd, which in the case of renovated l)utter is ditterent from 



iBer. Deut. Chem. Gesell., 32 (1899), p. 3186. 

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