MANURES. 35 



lants derive all their carbon from the atmosphere, the tendency 

 jas been with them to attribute the sole power to the inorganic 

 iatter. Indeed, Liebig himself gives credit to the organic portions 

 ply for helping the plant to dispose of the inorganic portions of 

 j5 food, which he seems to consider the most essential part of its 



ructure. That it is possible for the atmosphere to supply the 



.rbon and oxygen and nitrogen to plants in suflicient quantities, 

 ■ere may be no question ; but does it? is one which it is not so 

 • sy to answer. 



When one hundred pounds of wheat are burned, a quantity of 

 jlhes amounting only to a little more than one pound remains. 

 .11 the combustible part, or that which was consumed by the fire, 

 (insisted of organic matter, or oxygen, hydrogen, nitrogen and 

 <rbon. The remaining ash is the earthy and saline portion of the 

 ^|ieat. The very smallness of the quantity contradicts the notion 

 C the superior use of these materials in the food which has fur- 

 iihed them, and the large proportion of the other ingredients 

 ijght seem to warrant the belief that they were the efficacious 

 zmis. Such reasoning might be carried still farther, and the 

 1st quantity of any one ingredient present in the necessary food 

 cj plants be considered the controlling power in relation to the 

 \iole. 



But such reasoning is false in its whole extent. We know no 

 r son why we should attribute peculiar virtues to one more than 

 a)ther. A plant is a compound body, and all plants of the same 

 kid consist invariably of the same constituents, in the same or 

 nirly the same proportions. Each one must be regarded as 

 eiially necessary in the vegetable economy, and the food must 

 citain all, or the plant will not thrive. The different quantities 

 rmisite during the progress of the plant will be noticed hereafter. 

 Bt what has been stated is the true philosophy of farming. It is 

 tnupply to the growing plant the whole food it requires to perfect 

 itjwhole structure. If the soil already contains sufficient, no more 

 n«|d be given— if not, it must be furnished by manures. If any 

 oil ingredient is wanting, that one must be applied, and so with 

 tl: whole list. The soil may be rich in vegetable matter and yet 

 n( produce good crops, because it is destitute of salts. Supply 

 thje and its vigor is restored. And on the other hand it is well 



