AGB,1C\5LT\]RA1. ESSAYS. 



Nature and Constituent Properties op the Soil. 



It has been discovered by chemists, that the soil from which 

 we derive our subsistence, is composed of several simple sub- 

 stances, to wit, sand, clay, lime, and magnesia. But with res- 

 pect to the original uncompounded earths, there has been a di- 

 versity of opinion : some of the ancient philosophers supposing 

 that matter is the same in essence, and that the different sub- 

 «tances, considered as elements by chemists, are merely differ- 

 ent arrangements of the same indestructible particles; that the 

 varieties of the principles to be found in plants may be formed 

 from the substances in the atmosphere ; and that vegetable life 

 is a process in which bodies that the analytical philosopher is 

 unable to change or to form, are constantly composed or decom- 

 posed. An opinion has prevailed that loam is also an original 

 earth ; but it is believed that the evidence of its being merely an 

 artificial soil, produced by calcareous matters and animal and 

 vegetable manures, must preponderate against every opinion 

 to the contrary. In the improvement of agricultural science, it 

 is sufficient for the practical farmer to know that the most fer- 

 tile soil contains the greatest quantity of sand and clay for its 

 constituent ingredients, with a due proportion of each; and 

 that all other earthly substances are to make up the other con- 

 stituent ingredients of such a soil, by a judicious application 

 of them, as manures. Every soil in a productive state, has 

 been found to contain at least three of these simple substances, 

 or different kinds of earths, to wit, sand, lime, and clay, and 

 eometimes, also, magnesia. It has been found also, and perhaps 

 generally known by practical agriculturalists, that soils retain 

 moisture longer or shorter, accordbg to the proportions of these 

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