12 



ESSAY. 



and thus brings the matters dissolved in it, within 

 reach of the spongioles of the roots. A great deal of 

 unprofitable labor may be expended in growing a crop, 

 and every intelligent cultivator will use only just so 

 much as will pay, but should be satisfied with nothing 

 less. 



On the points enumerated we think that the limit of 

 success is very nearly reached by our best cultivators. 

 Concerning one other, and by far the most important, it 

 will be generally acknowledged that there is room for 

 very great improvement. We allude to the subject of 

 manuring, and what we shall have to say farther will be 

 in relation to it. It is a well known fact that if we 

 plant crops of any kind upon a soil year after year 

 without addition of any kind, the product will con- 

 stantly and rapidly diminish until in a short time it 

 ceases to be remunerative. It has been found from the 

 experience of all ages that the fertility of soil can only be 

 kept up by the addition of sundry substances, to which 

 collectively, the name manure has been given. Manure 

 may be defined as any substance, the addition of which 

 to the land tends to promote its fertility. Chemically, 

 manures can be divided into two classes; one class 

 including all those matters which plants take up as food 

 directly, and the other, such as assist the plant indirectly 

 in aid of its nourishment but do not act as food. The 

 distinction perhaps is not as yet perfectly understood, 

 but the first class includes all organized, vegetable 

 substances in a peculiar condition of decay, generally 

 known under the comprehensive term, humus or vege- 

 table mould. The second class comprises such other 

 substances as contribute in any way to the building up, 



