•^ AGRICULTURAL ESSAYS. 



earths. Those which contain the greatest quantity of sand, re- 

 tain it the shortest ; and those which contain the greatest quan- 

 tity of clay, retain it the longest. The first is a dry, the sec- 

 ond a wet soil. Lime and magnesia are intermediate between 

 these two extremes. They render a sandy soil more reten- 

 tive of moisture, and diminish the wetness of a clayey soil. 

 By mixing together therefore proper proportions of these four 

 earths, we may form a soil of any degree of dryness or mois- 

 ture, which can be effected by human agency. The degree of 

 its moisture must ultimately depend on the quantity of rain 

 which falls ; though it will be seen from what has been discov- 

 ered, that in certain soils, the farmer may, by apportioning the 

 different constituents of his soil, in some degree, mitigate the 

 evils which otherwise might result from extraordinary degrees 

 of drought and moisture, occasioned by the diversity of the sea- 

 sons. It may be considered a fundamental principle m agricul- 

 tural operations, that the four simple substances which have 

 been mentioned, do not constitute a fertile soil, in whatever pro- 

 portions they may be mixed. This has been proved by vari- 

 ous experiments. Among others, Giobert mixed together the 

 four earths, sand, clay, lime and magnesia, in the proper pro- 

 portions, to constitute a fertile soil ; and after moistening them 

 with pure water, planted several vegetables in them; but none 

 of them grew well, till he moistened his soil with water from a 

 dunghill. Lampodius planted different vegetables in compart- 

 ments of his garden, filled each with only one of the pure 

 earths, and v;atered them with the liquor which exuded from a 

 dunghill. They all grew, notwithstanding the diversity of the 

 soil. From the experiment of Giobert, it appears that the pure 

 earths cannot be mixed so as to make a fertile soil, without the 

 application of vegetable manure;''^ and by that of Lampodius, 

 that by an application of a suitable proportion of this manure 

 with either one of the simple earths, a productive soil may be 

 created. It would perhaps be a useless effort of the philosoph- 

 ic mind, to inquire respecting the origin of the first fertilizino- 

 principle which produced'^ the forests which generally 

 cover the earth in its primeval or natural state. It is sufficient 

 for the practical farmer to know that their foliage is continual- 

 ly deposited on the surface of the earth, and that the fertihty of 

 the soil is thereby increased. And if by cultivation we would 

 create or continue that fertility, we must by industry endeavor 

 to imitate the operation of nature, by restoring to the soil that 



* By vegetable manure is understood every vegetable or animal 

 substance, in a decayed or decomposed state. 



