1 jo The Principles of Part IV. 



quite undiflblved in water. This ihovvs 

 the ftrong attenuating power which marl 

 has, and which no other body can come 

 up to. It is obferved, that all clay grounds, 

 after they are marled, dry fourteen days 

 fooner than what they did before. This 

 is owing to the foil being more loofe, by 

 which means the water pervades it more 

 eafily. 



I KNOW that this opinion contradicts the 

 common "one, that marl is not fit for clay 

 grounds. From whence the latter has 

 taken its rife, I know not, if it is not that 

 bodies of fuch a limilar appearance cannot 

 be allowed to benefit one another. But the 

 experience of many counties where marl 

 is ufed, and where the foil is generally a 

 deep clay, contradicts this vulgar opinion. 

 The following experiment puts it beyond 

 all doubt. 



Exp. 39. 1 filled a pot with clay of the 

 fame kind I had ufed in the former experi- 

 ments, 



