224 CONSERVATIVE ORGANS. [LECT. V. 



When a Botanist examines a space of ground, 

 he forms an estimate of the nature of the soil by 

 observing the kind of plants, or weeds as they are 

 termed, which it naturally produces, and draws 

 his conclusions from the knowledge he possesses 

 of the relation which always subsists between the 

 plant and the soil. If the plants are those which 

 have much divided roots, he concludes that the 

 soil is pulverulent and easily penetrated ; but if the 

 roots are thick and fleshy, that, as these require a 

 humid soil, it is probable that it is damp and re- 

 tentive. Some kinds of plants grow on one soil, 

 but are never found on another ; some require a 

 large supply of carbonaceous matter, or a rich 

 fertile soil ; others, he knows, glean the little they 

 require in the more barren, and soon die in richer 

 spots. But the knowledge of the Botanist, al- 

 though it is an accurate guide to a certain degree, 

 in directing his judgment as to the value of un- 

 cultivated soils ; and is valuable in preventing him 

 from making bad speculations by introducing new 

 objects of culture into a place which cannot admit 

 of them ; yet it is of little avail in examining soils 

 under the immediate influence of cultivation. 

 The experienced eye of the farmer supplies much 

 of this defect. On too loose and poor soils the 

 roots of barley and other grains are long, but the 

 stems small and weak ; but in a richer and more 

 tenacious soil the roots are short, thick, and very 



