AGRICULTURAI, CHEMISTRY AGROTECHNY. 213 



Agricultural-chemical methods, K. IIaselhoff i .\</rih'iiltiucliciiiischc Untcr- 

 sKclningsmethodcii. Lcipsic, nui'J. /</;. /.>..',• rcr. in Xatiirtr. Rundschau, 25 

 {1010), A^o. 13, p. 167). — A small but comprehensive volume, coutaining chap- 

 ters on the examination of soils, fertilizers, feeding stuffs, seeds, plant ashes, 

 and milk and dairy jirodTu-ts. 



The microscopical examination of drugs, foods, and textile fabrics, A. 

 Schneider ( J/r/cA'.s Rpt., 19 {1910), No. 3, pp. 61-63. figs. 7).— This is a de- 

 scription of the microscopical characteristics of powdered vegetable drugs, 

 spices, cocoa, tea, coffee, and textile fabrics. 



Kjeldahl determination for nitrogen, C. Neuberg {Biocltcin. Ztschr., 2'f 

 {1910), No. 3-5, pp. .',35. )J6).— The author draws attention to the fact that 

 a great many beginners when liberating the ammonia from the amidomercuric- 

 sulphate (Hg(NH:i)2S04) employ too little alkali. On adding the sodium thio- 

 sulphate a portion of the sulphuric acid contained therein is liberated and 

 passes over into the distillate. To eliminate this possible source of error, the 

 author suggests using potassium xanthogenat instead of sodium thiosulphate and 

 in the proportion of 1 gm. for each 0.4 gm. of mercuric oxid. 



Determination of nitric and nitrous nitrogen, Salle (Ann. Chim. Analyt., 

 15 (1910). Xo. 3, pp. 103-105).— Take 0.5 gm. of the nitrates in a 600-700 cc. 

 flask and add 200 cc. of distilled water, 5 gm. of powdered zinc, from 1 to 2 gm. 

 of ferrous sulphate, and 50 cc. of a 36° Beaume soda solution. In the neck of 

 the flask place some glass wool and connect with the distilling apparatus. The 

 ammonia is distilled off and collec-ted as usual in decinormal sulphuric acid and 

 titrated. 



Detection of nitrates in the presence of oxidizing substances, M. E. Pozzi- 

 EscoT (Ann. Chim. Analyt., IJ, {1910), No. 11, pp. .',13, hll,, flg. 1; ahs. in 

 Ztschr. Angctr. Chcni., 23 {1910), No. 9, p. .'//N). — Oxidizing substances such 

 as chlorates and bromates, and halogen salts such as iodids and bromids. in- 

 fluence the reaction for detecting nitrates. This disturbing influence can be 

 eliminated by reducing the nitrate to an ammonium salt and testing for the 

 ammonia with Xessler's reagent. 



Analysis of Chili saltpeter, J. P. Virgili {Rev. R. Acad. Cien. Madrid, 8 

 {1909), Xo. 6. pp. 329-331). — A study of methods, with particular reference to 

 the presence of chlorid and perchlorid of soda and potassium chlorate. 



Methods of analyses of the potash salts, H. Roemer {CJicni. Engin.. 11 

 {1910). \(i. 3. pp. SO-S.'i). — A description is given of methods for the analysis 

 of potash salts for potash (platinic chlorid and perchloric acid methods), cal- 

 cium, magnesium, sodium, sulphur, chlorin, and moisture, together with the 

 methods of preparing the various reagents and the filters and the recovery of 

 the platinum from the wastes. 



Recovery of waste platinum, A. W. Blair {Jour. Indus, and Engin. Chem., 

 2 {1910). No. 3, pp. 102, 103). — The method in use at the Florida Experiment 

 Station consists in exposing the alcoholic platinum chlorid wash, containing no 

 ammonium chlorid, to direct sunlight until the supernatant liquid is i)refectly 

 clear and the platinum is deposited as a black substance. The supernatant 

 alcoholic liquid may either be rec-overed b.v distillation or poured off. The 

 potassium platinic chlorid from the (Jooch crucibles can be treated in a similar 

 mamu'r. The black platinum residues are treated in the usual way. 



Determination of small amounts of calcium in the presence of large 

 amounts of magnesium, A. Capi'kl {Kali, 4 {1910), pp. 77, 78; abs. in Chem. 

 Ztg., 3Jt {1910), No. 26, Rcpcrt., p. 105). — The solution, containing a known 

 amount of the sample, is acidified with hydrochloric acid, diluted, 50 cc. of a 

 saturated solution of aunnonium chlorid added, and brought to the boiling 

 point. A saturated solution of sodium bicarbonate is added, the solution boiled 



