ARBORICULTURE. 321 



The formation of peaty soils is produced from very opposite 

 causes, and it is interesting to contemplate how the same effect 

 may be produced by different causes, and the earth which 

 supplies almost all our wants may become barren alike from the 

 excessive application of art, or the utter neglect of it. Continual 

 pulverization and cropping, without manuring, will certainly 

 produce a hungry, barren soil ; and the total neglect of fertile 

 tracts will, from their accumulated vegetable products, produce 

 peaty soils, and bogs. Where successive generations of vegetables 

 have grown upon a soil, Sir H. Davy observes, unless part of 

 their produce has been carried off by man, or consumed by 

 animals, the vegetable matter increases in such proportion, that 

 the soil approaches to a peat in its nature ; and if in a situation 

 where it can receive water from a higher district, it becomes 

 spongy, and permeated with that fluid, and is gradually rendered 

 incapable of supporting the nobler classes of vegetables. Many 

 peat mosses seem to have been formed by the destruction of 

 forests, in consequence of the imprudent use of the hatchet by 

 the early cultivators of the country in which .they exist : when 

 the trees are felled in the outskirts of a wood, those in the 

 interior are exposed to the influence of the winds ; having been 

 exposed or accustomed to shelter, they become unhealthy, and 

 die in their situation ; and their leaves and branches gradually 

 decomposing, produce a stratum of vegetable matter. 



Lakes and pools of water are sometimes filled up by the 

 accumulation of the remains of aquatic plants; and in this case 

 a spurious peat is formed. The fermentation in these cases, 

 however, seems to be of a different kind. Much more gaseous 

 matter is evolved ; and the neighborhood of morasses, in which 

 aquatic vegetables decompose, is generally aguish and unhealthy; 

 while that of the true peat, or peat formed on soils originally dry, 

 is always salubrious. 



Soils may generally be distinguished from mere masses of 

 earth by their friable texture, dark color, and by the presence of 

 some vegetable fibre or carbonaceous matter. In uncultivated 

 grounds, soils occupy only a few inches in depth on the surface, 



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