l!>-0] SOILS FKltTILTZKKS. 323 



leiits usually accouipauiiMl the uKKU'raU' wati-r adilitions and this was increased 

 by partially excludiiifj liyht. However, tlie difTcrent conditinns imposed pro- 

 duced no noteworthy variations in the nitrogen content of the dry matter. 



In tlie pliosphoric acid tests, in addition to full and moderate water addi- 

 tions and the exclusion of light, a full water addition was made, together with 

 the addition of aluminum hydroxid and calcium carbonate. In contrast to the 

 nitrogen tests there was relatively little increase in yield with increasing 

 additions of available phosiihoric acid. The phosphoric acid assimilatiim was 

 smaller with the moderate water additions than with full water additions. The 

 aluminum and lime decreased phosphoric acid assimilation. 



Potash tests were also conducted but with contradictory results. 



On the basis of these results the authors attempted to develop curves show- 

 ing the relation between yield and analysis of crops as a basis for determining 

 fertilizer requirements of soil, and give an intricate mathematical analysis of 

 the sul)ject with apparently more or less doubtful results upon which to base 

 conclusions. They are of the opinion, however, that the data indicate that, 

 for those points on the yield curves for wliich the values obtained by dividing 

 the increase in yield by the yield are constant, the crops will show the same 

 percentage contents of nutritive constituents. 



Exi>lanation of nitrogen loss in liquid manure, E. Blanck (Landw. Vers. 

 Sta., [>4 (1919), No. 5-6, pp. 2S5-291). — The author answers criticisms of his 

 conclusions on the subject, and cites the results of numerous studies conducted 

 by himself and others to show that nitrogen losses through the evaporation of 

 anunonia begin when the total transformation of urea into ammonia is com- 

 pleted. 



Does peat litter absorb water from damp air? Tacke (Mitt. Ver. Ford. 

 MoorkuU. Dent. ReicJic, 34 (1916), No. 19, pp. 3S.?-5S»).— Experiments are re- 

 ported which showed that moss peat litter in finely divided condition absorbed 

 very little moisture from very damp air in a room. Excessively moist peat 

 litter under certain conditions lost moisture. Compressed balls of peat litter 

 in relatively dry condition absorbed no appreciable amounts of moisture. 



Theoretical study of nitrogen fixation by the electric arc, I-IV, C. P. 

 Steinmktz (Chcm. and Metall. lUujiti., 22 (1920), Nos. 7, pp. 299-304; 8, pp. 

 S53-357: 9, pp. 411-416; 10, pp. 455-462, fffi-s. i5).— This paper, in four parts, 

 gives the results of an extensive theoretical study of the problem of electric 

 arc nitrification. 



Part 1 deals with the chemical dynamics of the nitrogen-oxgen reactions at 

 the temperatures of the arc and during cooling, and includes equations of 

 reaction velocity and temperature equilibrium. Tables of thermal nitrifica- 

 tion constants, reaction periods, and velocities in air are also included. Part 

 2 deals with the effect of the rate of cooling upon the dissociation of NO and 

 includes cooling curves. Part 3 deals with multiple arcs with intermediate 

 cooling, and discusses cooling of the arc by adiabatic expansion and by 

 molecular diffusion. Part 4 deals with the kinetic aspects of the nitrogen- 

 oxygen reactions, taking up the effect of the arc in dissociating nitrogen, 

 oxygen, and NO, the influence of molecular vibration speeds, the probability law, 

 concentrations of NO, and principles of the electric are. 



Political and commercial control of the nitrogen resources of the world, 

 I-III, C. C. Gilbert (Chcm. and Metall. Engin., 22 (1920), Nos. 10, pp. 443-448; 

 11, pp. 501-504; 12, pp. 551-559, figs. 5). — This paper is in three parts. 



Part 1 gives a general review of the sources of nitrogen, including atmos- 

 pheric, nitrate ore, organic, and carboniferous deposit sources, together with 

 a description of the general aspects of the control of nitrogen resources in 

 2482°— 20 3 



