322 EXPEEIMEISTT STATION KECOED. 



of phosphoric acid increased. The decrease was, however, small in proportion 

 to the total amounts of the ingredients in the soil. 



Regarding humus acids of Sphagnum turf, S. Od^n (Ber. Deut. Chem. 

 Gesell., 45 (1912), No. 4, pp. 651-660; abs. in Jour. Soc. Chem. Indus., 31 (1012), 

 IVo. 7, p. 350; Chem. Ahs., 6 (1912), No. 16, pp. 2215, 2276).— The author first 

 reviews briefly different conceptions regarding the nature of humus acids, par- 

 ticularly as regards the question whether the reaction between alkali and 

 humus acid results in a peptonization of the colloidal material or in a chemical 

 precipitation of noncolloidal alkali compounds. He then describes a method of 

 preparing solutions of ammonium humate free from colloids and fi'om it, by 

 precipitation with hydrochloric acid, humic acid in suspension free from salts, 

 and reports studies of the reaction changes between humic acid suspensions and 

 alkali solutions as determined by conductivity measurements. 



The results of such measurements show that the interactions between ammonia 

 solutions and humus acid really resulted in salt formation. The neutralization 

 of sodium hydroxid with humic acid gave an equivalent of the acid of about 

 339. It appeared that humic acid is probably tribasic with a molecular weight 

 of about 1,000. Purified humic acid when dried at 100° C. was converted into 

 a hard mass which formed a black, lustrous powder. This powder did not go 

 into suspension in water and was not soluble in alkali solutions immediately, 

 but when treatment (with sodium hydroxid) was prolonged it gradually 

 passed into solution yielding a brown liquid. 



The influence of carbon upon nitrification, H. W. Clark and G. O. Adams 

 {Jour. Indus, and Engin. Chem., ^ (1912), No. 4, PP- 212-214). — Experiments 

 are reported which showed that the addition of easily assimilable carbohydrates 

 like sugar and molasses to sewage filter beds checked nitrification but at the 

 Bame time tended to clear the beds of organic matter. 



The present status of soil inoculation, K. F. Kellerman (Centhl. Bakt. 

 [etc.], 2. Ait., 34 (1912), No. 1-3, pp. 42-50, pis. 2).— This is the full text of a 

 paper of which an abstract has already been noted (E. S. R., 26, p. 520). An 

 annotated bibliography of American studies on the subject is appended to the 

 article. 



Azotogen, nitragin, and natural inoculating soil, A. KtJHN (Centbl. Bakt. 

 [etc.], 2. AM., 30 (1911), No. 21-24, 548-552).— The author takes exception to 

 the conclusions of von Feilitzen (E. S. R., 25, p. 123) regarding the relative 

 efficiency of azotogen and nitragin. 



Azotogen, nitragin, or inoculating soil, E. Teisler (Centbl. Bakt. [etc.], 

 2. Abt., 3.) (1912), No. 1-3, pp. 50-56). — The relative merits of these materials 

 for inoculating purposes are discussed on the basis of the work of von Feilitzen 

 (E. S. R., 25, p. 123), A. Kiihn (see above), and others. 



Inoculation experiments with nitragin for legumes, F. T. Shutt (Canada 

 Expt. Farms Rpts. 1911, pp. 114-116). — As in previous years, there was no 

 material benefit from the use of this material. 



Nitrogen enrichment of soils through the growth of clover, F. T. Shutt 

 (Canada Expt. Farms Rpts. 1911, p. 113). — Further observations on this subject 

 (E. S. R., 22, p. 321) showed that the soil continues to increase in nitrogen under 

 this treatment. 



The increasing of the ammonia fixing power of soils under the influence 

 of calcium carbonate, O. Lemmeemann and L. Fbesenius (Filhling's Landw. 

 Ztg., 61 (1912). Nos. 7, pp. 2',0-253. fig. 1; 8, pp. 214-285).— It was foimd.in 

 these experiments that the addition of calcium carbonate to soil in pots to the 

 extent of 1 per cent reduced the volatilization of ammonium carbonate and in- 

 creased the absorptive power of the soil for ammonia. Caustic lime had the 



