74 



SITith rise of temperature the solubility of both gases 

 decreases, that of oxygen a little more rapidly than 

 that of nitrogen. Accordingly the percentage of oxygen 

 in the dissolved gases is less at higher temperatures 

 and greater at lower temperatutes. Por instance, at 10° 

 C. the total dissolved gas is 2E.84 c.c. per liter and 

 34.47 percent of this is oxygen. At 30° the total gas is 

 15.64 c.c per liter and the oxygen percentage is 33.60. 

 Although ail of these figures were obtained for pure 

 water they will not be altered in important degree by 

 any dissolved substances likely to be present in the 

 soil solution. 



The solubility of carbon dioxide in water is 

 considerable greater than that of oxygen. At 20° G. and 

 760 mm. pressure of pure carbon dioxide one liter of water 

 will dissolve 878 c.c. of the gas. There seem to be no 

 accurate determinations of the solubility of the gas at 

 lower pressures, approximating the partial pressure of 

 the gas which uccur in soils. 1 However, this lack is 

 unimportant since the solubility of carbon dioxide in 



1. There is some data on the solubility of 

 atmospheric carbon dioxide in sea water, but the condi- 

 tions are not comparable, Por data see Clarke,- Data 

 of Geochemistry, U. 3. Geol. Survey, Bull. 616 . pp. 143- 

 145 (1916), and literature there cited. Carbon dioxide 

 does not obey Henry's law of the variation of gas sol- 

 ubility with pressure, henoe its solubility at low pres- 



