392 EUROPEAN AGRICULTURE. 



but. so far as any practical use whatever is to be made of this 

 fact, we must consider this nourishment as received through the 

 roots, and consequently through the medium of the soil in which 

 these roots spread themselves, and the manures by which it is 

 enriched. The soil therefore, as the basis of all vegetation, is the 

 great object of the farmer s consideration. 



LXV. THEORIES OF THE OPERATION OF THE SOIL. 



Soils may be considered in two points of view ; first, in ref 

 erence to their intrinsic or absolute character, and next, in ref 

 erence to the plants to the growth of which they are adapted. 

 In a preceding number, in speaking of the chemical analysis of 

 different soils, I think it appeared how little practical advantage 

 had as yet been derived from any experiments in this way 

 which had been made. The common properties of soil may be 

 distinguished by the eye or the feel with persons of experience 

 and practical observation ; but chemical examination may often 

 be of the highest importance in detecting the presence of some 

 mineral ingredient by which the cultivation of particular crops 

 may be hindered or wholly prevented. A friend, eminent for his 

 agricultural knowledge, pointed out to me a particular field, in 

 which all attempts to grow wheat had been unsuccessful, while 

 no such incapacity existed in the adjoining fields. In such a 

 case as this, one would look to the chemical analysis of the soil 

 to determine what ingredient was deficient, or what imfriendly 

 element existed or predominated in the soil to prevent the growth 

 of the plant ; and, this being ascertained, perhaps a remedy might 

 be found. But the extraordinary and minute exactness to which 

 the chemical analysis of the soil is sometimes carried, and upon 

 which many scientific persons insist, it would seem, can serve 

 little other purpose than that of producing despair of adapting 

 our cultivation to such diversified and minute variations. 



What portion of the soil is abstracted for vegetable food is not 

 yet determined ; and it is a singular fact, that, though analyt 

 ical chemistry has demonstrated that certain mineral substances 



