104 INDIAN CORN. 



conditions, it is necessary to know, not merely whether 

 they are present, but whether, also, they are in that 

 peculiar state in which the growing plant can use or 

 appropriate them. This condition chemistry has not 

 yet been able to discriminate with certainty. It may, 

 indeed, determine very correctly what proportion of 

 potash, or soda, or phosphoric acid is contained in a 

 cubic foot of any given soil ; but what the cultivator 

 needs to know is, how much of these substances it 

 contains in that state, that will enable them to minister 

 to the immediate wants of the plant. 



Nearly all soils contain, in a state of nature (as 

 elsewhere remarked), the principal elements of maize, 

 in greater or less quantities, and some of these ele- 

 ments are found in proportions even much larger than 

 the plant requires ; but their value depends entirely 

 upon their state of adaptation. If, from their peculiar 

 combinations or other causes, they are impervious to 

 the descending rains, and unfitted to the requirements 

 of vegetation, they add nothing to the present fertility 

 of the soil. There are fertilizing elements in the hard 

 impracticable rock, and the chemist can doubtless de- 

 termine the proportions of them ; but it does not fol- 

 low that the rock or any part of it is at present an 

 available soil for the growth of plants. The analysis 

 that reveals the relative quantities of plant-elements, 

 leaves the quality and fitness of them still obscure and 

 uncertain. 



If the chemist could indeed resolve the soil into its 

 elements, with an absolute precision and certainty as 



