Chap. XI. Of Blight. 147 



affords Five or Six Bufhels ; and that perhaps is fo 

 thin and lank, that the Expence of reaping and 

 threfhing it may overbalance its Value. 



That the falling down of Wheat does caufe the 

 Ruin of the Crop, is well known -, but what cauies 

 it to fall, is not fo plain. 



And, without knowing the true Cau fes, 'tis not 

 likely that a Remedy fhould be found againft the 

 Difeafe. 



I take this Weaknefs of the Stalks, which occa- 

 fions their falling, to proceed from want of Nou- 

 fifnment, want of Air, want of the Sun's Rays, or 

 of all Three. 



One Argument, that it lodges for want of Nou- 

 rifhment, is, that a rich Acre has maintain'd a Crop 

 of Five Quarters Handing, when another poorer 

 Acre was not able to fupport a Crop from falling, 

 which was but large enough to have brought Three 

 Quarters, if it had flood : and this in the fame 

 Year, and on the fame Situation. And 'tis very 

 plain, that if one Acre was twice as rich as the other, 

 it mud be able to nourifh Five Quarters better than 

 the other could nourifh Three Quarters. 



Air is neceffary to the Life and Health of all Plants, 

 tho' in very different Degrees : Aquatics, which live 

 under Water, are content with as little Air, as their 

 Companions the Fillies. 



But Wheat, being a terreftrial Plant, (tho' in Win- 

 ter it will live many Days under Water, whild the 

 flow Motion of its Sap gives it litle or no Increafe), 

 requires a free open Air, and does not fucceed fo well 

 in low fheltery Places, as upon higher and opener 

 Situations \ where the Air has has a greater Motion, 

 and can more eafily carry off the Recrements from 

 the Leaves, after it has fhaken off the Dews and 

 Rains, which would otherwife fufFocate the Plants ; 

 and therefore the Leaves are made fo .fufceptible 

 of Motion from the Air, which frees them from 



L the 



