OF AGRICULTURE. 5 



the greater part of it is dissipated, but there remains 

 a white ash. This ash is found on analysis to contain 

 most or all of the constituents enumerated in the 

 first column of the following Table. 



Constituents of Plants and Animals. 



Sulphur. 

 Phosphorus. 



Barer substances than these are also sometimes 

 found. It will be my duty, in subsequent lectures, 

 to call your attention in some detail to what is 

 known as to the occurrence, and the offices, of the 

 various mineral or ash -constituents in plants. It 

 will suffice here to say, that the ash of one and the 

 same description of plant, growing on different soils, 

 may, so long as it is in the vegetative or immature 

 state, differ very much in composition. Again, the 

 ashes of different species, but growing on the same 

 soil, will differ very widely in the proportion of their 

 several constituents. But it is found that the nearer 

 we approach to the elaboration of the final products 

 of the plant — the seed for example — the more fixed 

 is the composition of the ash of such products of one 

 and the same species. In other words, there is very 



