226 PHYSICAL PROPERTIES OF SOIL. 



There is yet another view of the effect of the con- 

 version of geine into water. Allowing, as has been 

 asserted, that all land, forest or cultivated, produces 

 annually about the same amount of carbon, then the 

 amount of water, transpired above from woodland in 

 15 hours, is nearly equal to dissolving one-half of the 

 geine, to produce that amount, leaving the balance 

 to be derived from air. An acre of woodland pro- 

 duces, it is said, annually, about 1,783 English 

 pounds of carbon. If water dissolves only -I- part 



A * 2500  



of its weight of humus or geine, then 3,565,000 dis- 

 solve 1,426 lbs., which, at 58 per cent, carbon is 

 equal to 827 lbs. 



Leaving to be derived from air, 956 lbs. 



1783 lbs. 

 This is taking geine in its most insoluble state. The 

 great increase of solubility when combined with alkali, 

 would render the annual amount of water transpired, 

 equal to dissolving, as geine, all the carbon which 

 has been added to the plant. 



The advantage of a light porous open soil are now 

 evident ; it lets in air, it lets off steam. This steam 

 charged with carbonic acid, acts on silicates, elimi- 

 nates alkalies, waters and feeds plants. Salts, geine, 

 and barren pine plains, are the elements of a western 



