100 ON THE FOOD OF PLANTS. 



He also says, " I shall beg leave to remark, 

 " that as the several land animals have their re- 

 " spective diets, so have the terrene plants their 

 " several soils, from whence they derive their 

 " nourishment ; as some animals feed on flesh, 

 " others on fish, &c., so do plants love, some 

 " clay, others loam, sand, or gravel. Nor is this 

 " all we ought to observe ; we must consider, 

 " likewise, how beneficial to every plant is a 

 " right exposure ; whether in a vale, the sides 

 " or tops of hills, exposed to the south or north 

 " winds ; whether inland, or near the sea, for 

 " it is a proper exposure that keeps a plant in 

 health." 



Bradley, Hitt, and Miller, consider the food 

 of plants to be salts, which every species of earth 

 more or less contains within itself; and that 

 according to the proportion of salts, contained 

 in each kind of soil or manure, will its proli- 

 ficacy be. f 



That soils, and vegetable and animal matters, 

 may be found to produce salts, under certain 

 circumstances and chemical processes, I have no 

 doubt ; but this does not prove it to be necessary 

 that every substance, or any substance, con- 

 taining the basis or elements of salts, should 

 undergo this process, and be formed into 

 salts, before it can be in a state to constitute 



