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Entirely of these bodies termed nutritive, would be unfit to produce good 

 crops. It is not a matter of indiflference what constitutes the basis, or 

 substratum of soils. This must be a peculiar medium, having certain 

 peculiar relations to water and other bodies, which, if not secured by 

 and in their physical or mechanical properties, would render the labors 

 of the farmer of no avail. Most of the earths — by which is meant all 

 the above described substances, except the acids and chlorine — possess 

 some absorbent properties. Alumina, however, when pure, or as com- 

 bined with silica, (its most usual state,) ranks high in this important 

 particular. The rapid absorption of ammonia by clay, renders it (the 

 clay) a receptacle or reservoir of this substance, which is of so much 

 value as nutriment to plants, and which is thus derived from the air, 

 manure, &c., and retained for future use.* 



Oxide of Iron. — This element of soils is well known to every farmer, 

 under the name of iron-rust. All soils contain it very much in the same 

 way as the bog-iron ore, which is an impure oxide of iron, and resembles 

 it in some respects. It has not yet been determined that the oxide of 

 manganese is an essential constituent of any class of plants, though it is 

 found in small quantities in most of them. Its presence, however, is 

 thought to be, by some, wholly accidental. Its necessity as an element 

 of a fertile soil, though required only in small quantities, is inferred 

 from the fact, that its entire absence from a soil, renders it unfit to 

 produce perfect crops. This fact shows us that the importance of an 

 element is not always to be inferred by. its abundance, either in the plant 

 or in the soil upon which it has grown. Silex, which usually forms so 

 large a portion of most soils, is no more an essential element than is the 

 oxide of iron or manganese, which usually forms so small a portion of 

 soils. One element is just as essential for the due perfection of the plant 

 in all its parts, as another. The organic elements of the soil are just as 

 important to the secuing of a good crop, as are the inorganic elements of 

 which we have given a description, but no more so. It is not because 

 the organic are not essential, that Ave have said nothing of them, but 

 because our soils are tolerably well supplied with them, and because the 

 manures which the farmers are generally in the habit of putting upon 

 their soil, usually contain a much larger portion of organic than of 

 inorganic matter. There is, therefore, a greater liability, in almost every 



*Eminon8. 



