AGRICULTURE WITH CHEMISTRY. 143 



necessary to enter into a description of them, in a Trea- 

 tise which has principally in view such circumstances and 

 matters as have not hitherto, on chemical principles, 

 received satisfaclory explanation. Under-draining at this 

 time is very deservedly in great estimation, and is becom- 

 ing the general pradlice. It saves much waste of ground, 

 more completely answers the intended purpose, is of 

 longer duration, and ultimately leSs expensive than any 

 other kind of draining. A method has lately been disco- 

 vered, and pratlised with success, by which, in many places, 

 the upper stratum is drained by the assistance of the mi- 

 neral strata beneath it, through which the water is made to 

 drop, and in this manner taken from the surface. Drain- 

 ing is not only to be accomplished by these judicious 

 methods, and by open drains, but lands are to be made 

 dry by such a mechanical alteration in the component 

 parts of the soil as render it less retentive of moisture. 

 In stiff lands this may be effe<fled by lime, chalk, marl, 

 coal-ashes, brick-dust, or calcined clay, and by sand, 

 when applied in large quantities, whilst the too great 

 tendency in sandy or light soils to part with moisture is 

 to be corred^cd by other applications. 



FAL- 



