UNCLE IN ENGLAND. 99 



derive their food ; either at once, from the 

 growing plant, or at second hand from their prey, 

 who had been nourished by it ; and that vegeta- 

 bles, in their turn, live on all that has already 

 lived and vegetated. There is a continual suc- 

 cession of production and decay ; for it is by 

 decay, and the decomposition that follows, that 

 nature restores to the ground those substances of 

 which it is robbed by vegetation. 



But when the produce of the soil is removed 

 for the use of man, and not left to immediate 

 decay, the agriculturist is obliged to assist nature, 

 by supplying other decayed vegetable matter, or 

 else, by mixing it with some artificial manure. 

 To do this more effectually, people are obliged 

 to study the principles of the different soils, in 

 order to know what species of manure should 

 be applied to fertilize, or to correct them ; to 

 render one, for instance, more alkaline, or to 

 lessen the siliceous nature of another. Even 

 rest restores to the earth some of its productive 

 powers; and when it is ploughed up, and long 

 exposed in what is called a fallow, the air has 

 considerable influence in improving it. 



This led to a conversation on the many varie- 

 ties of soils ; and my uncle says I shall become 

 acquainted with them in time. They are all 

 well known to good farmers, who can thereby 

 determine what crops are adapted to each. 

 Who could have thought, Mamma, that all this 



K 2 



