70 CHRONICLES OF A CLAY FARM. 



you all it ever got from the soil.' But the bulk, the 

 weight, the great mass of its vegetable structure 

 where is that gone ? 



" Into the Air : 



And what seemed corporeal hath melted 

 Like breath into the wind !" 



The weight, the bulk, the vegetable mass, of a 

 crop, is simply, its Carbon. COMBUSTION just un- 

 does what GROWTH did : and nothing more. It re- 

 combines the Carbon of the plant with the Oxygen of 

 the air, and their union is Carbonic-acid gas : the 

 very substance which the leaves of a plant feed upon 

 in the air where it is presented to them in its gaseous 

 form in which alone they can absorb it : they do ab- 

 sorb it ; and in their clever little laboratory they pick 

 out the carbon, and return the oxygen; just as our 

 own lungs take up the oxygen and return the nitro- 

 gen. Multiply the two surfaces of an oak -leaf by the 

 number of leaves on the tree, and you will be able to 

 form some idea of the enormous surface, which the 

 plant annually presents to the atmosphere to carry on 

 this work of absorption. 



But the Roots what is their use then ? 



Examine them through a Microscope, and you will 

 see that, as the Leaves are adapted to intercourse with 



