M. De Gasparin on the Classification of Soils. 87 



the objects of agricultural interest is small, and were we to 

 conduct a course of agriculture, according to the order of fa- 

 milies, we should have only shi-eds of these families, Avhich, de- 

 tached from their natural alliances, would exhibit nothing but 

 disorder, so soon as the intermediate links were withdrawn 

 which maintain the order of theu" connection. What, then, 

 under these circumstances, is to be done I The answer is 

 clear, — we must combme together the plants whose kind of 

 ctiltivation has the gi'eatest analogy, and we should thus 

 have, for example, 1st, trees ; 2d, the trees and shrubs which 

 yield an annual crop (such as fi'uit-trees, mulberries, vines) ; 

 3d, the feculent grains (wheat, oats, buck- wheat, &c.) ; 4th, 

 the plants with oily seeds (the poppy, colza) ; 5th, the 

 plants which yield fodder (lucerne, spurry, ryegrass) ; 6th, 

 plants used in weaving (lint, hemp) ; 7th, plants used in 

 dyeing (dyer's woad or glastum) ; 8th, the oleraceous plants (pot- 

 herbs, spinage, chiccory); 9th, roots (beet, carrot, madder), &c. 

 &c. According to this method, classes are formed in which 

 the natiu*al affinities of plants are often broken, but wliich, on 

 the other hand, present another kind of affinities, such as pro- 

 ceed from their mode of cultm'e. They are, therefore, natural 

 classes in relation to farming, whilst they cease to be so con- 

 sidered in the light of natvu'al history. This is a method 

 which has been followed in regard to medical substances, 

 articles of food, &c. Chemistry itself classes natural bo- 

 dies in a manner different from what mineralogy does, be- 

 cause the view it takes of them is different. Thus, not only 

 the practical arts, but the pure sciences themselves, modify 

 classification, according to the object they have in view, with- 

 out at all changing the natm^al relations of bodies ; they detei- 

 mine that one of their properties which ought to predominate 

 in the order they impose. 



In agronomy, therefore, it is no longer simple substances, or 

 bodies in their individual condition, such as a plant, or crystal, 

 we have to examine ; but it is mixtm-es of many of these sub- 

 stances, of which we form individuals only by abstraction, as 

 we do in rocks, formed as they are by the union of many mine- 

 rals. But this intellectual operation which regards the liabitual 

 union of several substances and forms from them one collective 



