48 Manures — their Applied ion. [Jan., 



but effectually, decomposed; and the parts are fitted for entering 

 into new combinations, and for adding to the substance of the 

 living plants. Thus, instead of nuisances, nature furnishes ma- 

 nure, and no substance whatever is lost. This is one of the beauti- 

 ful and admired l&ws of nature; and though we cannot investi- 

 gate her very minute operations, we are able, by observation, to 

 learn much^ and by industry to derive great advantages. 



A great deal has been said about the fertility of plants. Pul- 

 verised earth, water, as an element, carbonaceous matter, in a 

 soluble state, and various gaseous substances have been success- 

 ively in repute; some plants have been supposed to draw part of 

 their food from the atmosphere, in a larger proportion to others; 

 and it has been thought that grain and green crops require to be 

 supported with food proper to each class; and that one particular 

 crop, on that account, exhausts the substance on which it feeds, 

 if too frequently repeated. 



Practice has introduced more discoveries into agriculture, as- 

 sisted by observation, than science. At the same time, though 

 the man of science will not presume to dictate to the skilful prac- 

 tical farmer, he may not only improve, but enlighten, and even 

 give digniiy to agriculture as an art, by rendering it, in some de- 

 gree, a science also. 



The application of manures depends on the natural state of the 

 soil, and on the purposes for which it is to be applied. Observa- 

 tion and experience determine how to act, and what to apply; 

 also how and v.^hen the application should be made. Yet it would 

 be of important use to the farmer, in remarkable cases, to call in 

 the aid of science. Many expensive trials have been made in 

 redeeming some soils, or turning them to useful purposes, in vain. 



The farmer knov/s, or ought to know, that some soils want so- 

 lidity, and others have too much; that some exceed in cohesion, 

 others in looseness, and that a moderate degree of these properties 

 is considered essential to fertility. With this view sand is applied 

 to tenacious clay; and clay on sand and gravel. But these ap- 

 plications are not made in the strict order of manures; they are 

 mechanically w^anted, in order to give to the soils a proper con- 



