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TNTROnUCTOKY REMARKS. 



merely by preserving its own original substance, tbat 

 land in wood has the advantage of cultivated ground. 

 Whatever is extracted from the latter, in the form 

 of vapour, falls again, when condensed, in the shape 

 of rain or dew ; but, instead of descending wholly 

 on the same spots from whence it rose, it is, of 

 course, diffused over the whole space which the 

 clouds containing it may happen to cover, and woods; 

 and moors have as good a chance of receiving it, on 

 its return to the earth, as the ground in tillage. 

 The part of it which falls, either on the cultivated 

 fields, or the naked wastes, may be again evaporated 

 before it has had time to be productive of any bene-, 

 fit, but the portion of it which the woodlands im- 

 bibe, is retained to enrich the soil ; for, the umbrage 

 excluding the rays of the sun, there is no possibility 

 of its being extracted a second time. Land covered 

 with trees, therefore, while it never loses any thing, 

 receives, with every fall of rain or of dew, a tribute 

 from the riches of the cultivated part of the country. 

 The advantage derived from this source is greater 

 than will be credited by those who are not aware 

 how much of the substances proper for vegetable 

 nutriment, are exhaled from the land in a gaseous 

 state, during the dry season of the year. 



But the principal way in which wood becomes in- 



2 



