AGRICULTURAL CHEMISTR1 . 527 



Oxidation of atmospheric nitrogen in the high tension arc, A Sta\ enh \< . i \ 

 (Ber. Deut. Chem. Gesell., 88 (1905), No. 9, pp. 9171 9177; abs. in Jour. Chem. Soc. 

 [London], 88 i 1905), No. 514, H, p. 511 >. "Air was forced al known rates through 

 B cooled porcelain tube containing two iron electrodes; the tension was aboul 20,000 

 volts and the currenl 0.07 ampere, the discharge being a continuous greenish-yellow 

 flame. Large quantities of oxids of nitrogen were formed, the yield being a maxi- 

 mum when air was forced through al a velocity of 180 liters per hour. It is impossi- 

 ble to completely condense all the oxids of nitrogen formed in this manner even bj 

 means of liquid air." 



The examination of cyanamid and applications of the method, R. l'ri.<.i n 

 (Oaz. Chim. Ttal, 85 (1905), U, pp. .v.v -282; abs. in Chem. Centbl., 1905, II. No. 14, 

 p. 1058). It is stated thai cyanamid reacts with silver nitrate in presence of 

 ammonia to form silver cyanamid and nitric acid, 1 cc. of hundredth-normal silver 

 solution corresponding to 0.00021 gm. cyanamid. 



To the silver nitrate made slightly alkaline with ammonia add the cyanamid solu- 

 tion drop by drop with shaking and gentle warming. Filter after the solution has 

 cleared and wash the precipitate with weak ammonia, add 3 or 4 drops of iron alum 

 ami nitric arid to the lilt rate, and titrate with hundredth-normal rhodan-ammonium. 

 The method is applicable to commercial calcium cyanamid (lime nitrogen), the solu- 

 tion of the material to be tested being obtained by L2 hours' standing in the cold 

 and each cubic centimeter of hundredth-normal silver nitrate used, corresponding to 

 0.0004 gm. calcium cyanamid. 



Expulsion of ammonium salts after precipitation in their presence, P. I \ \ 

 nascii (Jour. Pratt. Chem., n. ser., 72 I 1905), No. 18, p. 88; abs. in .Inn,-. Chem. Soc. 

 [London], 88 (1905), No. 515, II, p. 611). — " Large quantities of ammonium chlorid 

 are expelled from solutions by evaporation with concentrated nitric acid containing 

 nitrous acid." 



The true atomic weight of nitrogen, G. D. Hinkicus ( Compt. Rend. Acad. Sci. 

 [Paris], 14" (1905), No. ..'-',, pp. 1590, 1591).— Evidence is cited to show that the 

 atomic weigh! of nitrogen is exactly 14. 



A revision of the atomic weight of potassium, E. II. Archibald l Proc. and 

 Trims. Roy. Soc Canada, .'. ser., 10 I 1904), s,r - Til, pp> 47-58, fig. I). A series of 

 studies of the atomic weight of potassium based upon analysis of potassium chlorid 

 Is reported, the average results giving an atomic weighl for this element of 39.14. 



On the determination of assimilable phosphoric acid in soil, A. S. Kin \-ui:\ 

 {'/Jmr. Opuitn. Agron. (Russ. Jour. Expt. Landw.),6 (1905), No. 4, PP- 4S7-456). - 

 The author recommends \ per cent oxalic acid as a reagent for determining the 

 assimilahle phosphoric acid in soils and reports tests of the reagent OD Hi' sample- of 

 chernozem soil. In all cases the more fertile soils yielded the larger amount of 

 phosphoric acid soluble in the reagent. Soils treated with manure were also found 

 to contain more phosphoric acid soluble in the reagent than untreated soils. — 



I'. FIREMAN. 



Action of phosphates on platinum when heated with it in the presence of 

 carbon, W. 1'. 1 1 1: \i>iu:\ I Proc. Colo. Sci. Soc, 8 (1905), pp. 95-49; abs.inJour. Aim,-. 

 Ukem. Soc, 97 1 1905 j, No. //, /.'< v., />. 615 |. -The deterioration of platinum crucibles 

 when repeatedly used for the ignition of ammonium-magnesium phosphate is 



explained as due to the formation of platinum phosphid. 



A study of various methods for the determination of aluminum in the ash 

 of plants, H. Pellet and C. Friboueg (.1////. Chim. Analyt., 10 I 1905), No. 10, pp. 

 ;??<;-.;si |.- Tests of the methods of Carnot, Lasne I E.8. R.,7,p.915),and Sainte-Claire- 

 Deville, as modified by L'H6te, are reported. Asa result of these tests the author 



prefers the method of Carnot, although he considers that of Lasne equally g 1 hut 



somewhat longer. 



