THE SOIL. 69 



bottom unaltered. Pour the same liquor through 

 the barrel containing the charcoal, and only pure 

 water will pass through. The reason for this is that 

 the charcoal retains all of the impurities of the 

 liquor, and allows only the water to pass through. 

 Charcoal is often employed to purify water for 

 drinking, or for manufacturing purposes. 



A rich garden-soil contains large quantities of 

 carbonaceous matter; and if we bury in such a soil 

 a piece of tainted meat or a fishy duck, it will, in a 

 short time, be deprived of its odor, which will be 

 entirely absorbed by the charcoal and clay in the 

 soil. 



Carbon absorbs gases, as well as the impurities of 

 water ; and, if a little charcoal be sprinkled over 

 manure, or any other substance, emitting offensive 

 odors, the gases escaping will be taken up by the 

 charcoal, and the odor will be very much modified. 



It has also the power of absorbing earthy matters, 

 which are contained in water. If a quantity of salt 

 water be filtered through charcoal, the salt will be 

 retained, and the water will pass through pure. 



"We are now able to see how carbon renders the 

 soil retentive of manures. 



1st. Manures, which resemble the brown liquor 

 of barn-yards, have their fertilizing matters taken 

 out, and retained by it. 



2d. The gases arising from the decomposition 

 (rotting) of manure are absorbed by it. 



3d. The soluble earthy portions of manure, .which 

 might in some soils leach down with water, are 



