RFXENT WORK I\ ACRirUlJURAL SCIliXCE. 



CHEMISTRY. 



The direct determination of potassium in the ash of plants, E. M. East 

 {Jour. Amer. Chem. Soc.^, 26 {1904), ^^o. 3, pp. 297-300).— In the method proposed 2 

 to 3 gm. of substance is incinerated with ammonium nitrate, and the determination 

 of potash in the ash thus obtained proceeds as follows: 



"Transfer to a beaker with only a few drops of hydrochloric acid and heat to 

 boiling. Add to the hot solution barium hydroxid solution saturated at 32°, suffi- 

 cient to iirecipitate interfering salts. From 3 to 5 cc. are usually enough, providing 

 the hydrochloric acid has been used sparingly. Digest one hour, filter hot, and 

 wash with hot water. Precipitate the barium as sulphate l)y a sodium sidphate 

 solution made up of strength equiA'alent to the barium hydroxid solution used. 

 Digest 5 hours, filter, and wash. Evaporate down to about 25 cc. in a platinum 

 dish. Add a drop or two of hydrochloric acid and the calculated amount of chlor- 

 ])latiuic acid needed to convert all the alkalis into chlorplatinates. Proceed as in the 

 Lindo-Gladding method for fertilizers. Transfer all the double salt to the filter 

 after the first addition of 10 cc. of the ammonium ehlorid solution. The interfering 

 salts of magnesium and calcium will all be dissolved on the first api^lication. After 

 transferring, 5 Avashings of 5 cc. each are sufficient to clear the double salt from im- 

 purities; then wash with alcohol, dry, and wash through the filter with hot water 

 as usual." 



A method for the direct determination of alumina, C. E. Rueger {Engineer 

 and Mln. Jour., 77 {1904), ^o. 9, pp. 357-859). — A modification of Wohler's method, 

 in which alumina is precipitated from a slightly acid solution by means of sulphur 

 dioxid, is described. 



Eudiometric and g-ravimetric methods of determining ammonia, E. Riegler 

 {Ztschr. Analyt. Chem., 43 {1903), p. 677; abs. in Chem. Ztg., 28 {1904), No. 9, Repert. 

 No. 2, p. 21). — Methods based upon the fact that ammonia or ammonium salts when 

 acted upon in alcoholic solution T)y an excess of iodic acid form ammonium triiodate 

 (NH4)H.2(l30a), which yields nitrogen when subjected to the action of hydrazin sul- 

 phate, are described. The nitrogen gas may be collected and measured in a Knop- 

 Wagner azotometer, or the precipitated ammonium triiodate may be collected on a 

 filter, dried, and weighed. The weight thus obtained multiplied by 0.0314 gives 

 ammonia. 



On the determination of nitrites in the absence of air, J. K. Phelps {Ztschr. 

 Anorgan. Chem., 38 {1904), No. 1, pp. 113-116; ahs. in Chem. Ztg., 28 {1904), No. 13, 

 Repert. No. 3, p. 35). — The author describes the apparatus used and methods followed 

 in making this determination in an atmosphere of carljon dioxid. 



The determination of total carbon in coal and soil, S. W. Pakr [Jour. Amcr. 

 Cliem.. Soc, 26 {1904), No. 3, pp. 294-297, jig. 1). — Combustion of the substance is 

 effected by means of sodium peroxid in a calorimeter by a method previously 

 described by the author. « The resulting sodium carbonate after being boiled to free 

 it from peroxid and oxygen is decomposed by sulphuric acid and the carbon dioxid 

 evolved collected and measured in an eudiometer of special design, which is described. 



«Jour. Anier. Chem. Soc, 22 (1900), No. 10, pp. 646-^52. 

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