Sett. II. Agriculture and Vegetation. \ 87 



5. THERE is yet another way of deftroy- 

 ing thefe weeds ; and that is, by marl. I 

 have feen broom effectually killed by marl. 

 I have feen a crop of wheat growing on a 

 field which was partly marled and partly 

 not. That part of the field on which marl 

 had been laid, was free from all weeds, 

 while the other unmarled part was full of 

 them. The fame wheat was fowed over 

 the whole field. I can account for this 

 effeft of marl in no other way than this, 

 that the grain is brought up fo fpeedily as to 

 be able to choke and deftroy thefe weeds. 



SECT. II. 



Of a ivef foil. 



THERE is not a greater enemy to ve- 

 getation than the too great moifture 

 of the foil. It is always owing either to 

 a ftratum of rock, or of clay, generally 

 the latter, below the furface, which not 

 allowing the rains to pafs through, they 



can 



