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S E C T I O N II. 



Of the Conjiliut'ion of fertile Sollsy and the Method of ejlmating 



their Fertility. 



The moft fertile foil is that which contains the greateft quan- 

 tity of the food of thofe vegetables that nourifh men and ufeful 

 animals, and adminifters it to them with due oeconomy. 



The firft effential requifite therefore to a fruitful foil is, that 

 it contain a fufEcient quantity of the three or four fimple earths 

 abovementioned, and of the foluble carbonaceous principle. The 

 other requifites are, that the proportion of each, and general 

 texture of the foil, be fuch as to enable it to admit and retain 

 as much water as is neceffary to vegetation, and no more. 



Now we have already feen that the retentive powers of 

 moifture are very different in the fimple earths : therefore the 

 proportions in which the fertility of a foil requires them to be 

 mixed muft be different in climates and countries that differ 

 confiderably in moiflure ; in the drier they muft be fuch as are 

 moft retentive, in the moijler fuch as fufter it to pafs or evaporate 

 more eafily. 



The fame remark extends to fituation. Lands on a plain 

 fhould be fo conftituted as to be lefs retentive of water than thofe 

 fituated on a declivity, as is very evident. 



.;;)no'j bn.': 



So 



