70 ON THE CULTIVATION OF THE EARTH. 



most simple observer, that notwithstanding the 

 apparent ultimate destruction of every visible 

 substance, the same quantity of both animate 

 and inanimate substances always exist, and it 

 may be justly concluded, that the process of 

 nature is carried on by a kind of transmutation, 

 or change in the relative connection of matter, 

 brought about by certain processes of death and 

 decomposition, and restored again by the action 

 and dissemination of certain principles of life and 

 recomposition ; we cannot, by artificial means 

 alone, effect 6ach a combination of those princi- 

 ples, or elementary substances, as to form either 

 animals or vegetables, and we are therefore inca- 

 pable of demonstrating by synthesis. 



On this point, Sir Humphry Davy remarks, 

 " What may be our ultimate view of the laws 

 " of chemistry, or how far our ideas of ele- 

 *' mentary principles may be simpUfied, it is 

 " impossible to say ; we can only reason from 

 " facts ; we cannot imitate the powers of com- 

 " position belonging to vegetable structures, but, 

 " at least, we can understand them; and as far as 

 " our researches have undergone, it appears, that 

 *' in vegetation, compound forms are uniformly 

 " produced from simpler ones : and the elements 

 " in the soil, the atmosphere, and the earth, 

 " absorbed and made parts of beautiful and 

 *' diversified structures." 



