32 FARMER'S ASSISTANT. 



presence of other fertilizing matter in the soil, that over- 

 balances the effects of the iron ; or, that the color is chiefly 

 owing to some other cause. 



When earths have been made as dry as they can be, by 

 exposure to the air, they still contain a considerable quan- 

 tity ot water; the more clayey kinds containing about a 

 fourth of their weight; while those which are light and 

 sandy hold from a tenth to a twentieth part only of thu 

 fluid, according as the sand predominates more or less. 



It would seem that this circumstance is principally what 

 gives to clayey soils the advantage over those which are 

 light and sandy ; the former, holding more water y are ena- 

 bled to impart to the growing plants more of this necessary 

 food than the latter, particularly during spells of dry 

 weather. The stiff and clayey soils may therefore be said* 

 on this account, if on no other, to contain more of the food 

 of plants than the light sandy ones. 



But clays may, nevertheless, be too solid and compact to 

 admit the extension of the roots of plants in search of this 

 food ; and, in such case, the stores of this nutriment are 

 only to be unlocked by the application of sand, or some 

 other substance calculated to destroy the quality of com- 

 pactness and adhesion in the soil. 

 See MANURES. 



Something shall now be said of earths, in regard to their 

 forming different soils. 



There are a variety of these ; such as the sandy, gravelly, 

 loamy., clayey, marley, chalky, mucky, turf, and peat soils. 

 There are also soils formed of a mixture of some of these 3 

 such as the sandy -loam, gravelly -loam, sandy- clay, gravelly- 

 clay, Sec. 



The sandy soil is that in which sand predominates; but 

 \vlrich, at the same time, contains a sufficiency of other 

 earthy matter to make it more or less retentive of moisture, 

 and thus becomes endued with various degrees of fertility. 

 A pure sand is wholly barren ; being nothing more than a 

 collection of very minute pebbles, which are usually of the 

 stone we call flint ; though sometimes they are of calcareous 

 stone, as we have before mentioned. 



Where a sandy soil is underlaid, and at no great depth, 

 with what is usually called a hard pan, it adds 'greatly to 

 the retentiveness of the soil, and of course to its fertility. 



Sandy soils are usually of a yellowish, or redish, cast. 

 Sometimes they are grayish ; and frequently they are dark- 

 colored. The latter are usually the most fertile : Generally, 

 they are very productive; the yellowish and redish are 

 commonly the least so; and the grayish usually holds & 

 middle station between the two extremes. 



