[ '45 ] 



Hence they fhoud be applied, not indifcriminately, but ac- 

 cording to circumftances, to be indicated in the fequel. 



Pounded bones form alfo a manure much ufed in the neigh- 

 bourhood of great towns. They gradually depofite their oily 

 part, which contains a large proportion of animal coal which 

 is extricated by putrefadlion, and phofphorated calx. Hence 

 Bone-afh is alfo ufeful. 



Sea-weed, particularly if mixed with earth, foon putrefies 

 and makes a good manure. 



Sweepings of Ditches abound with putrid matter from de- 

 cayed vegetables, and hence form a manure. 



Old Ditches, expofing a large furface to vegetation, contain, 

 when deftroyed, a quantity of decayed vegetables, which putrefy 

 and make a good manure; but in this and the former cafe, 

 it may be proper to diftinguifh of what foil they are compofed, 

 for reafons that will hereafter appear. 



Fallowing is the principal operation by which exhaufted 

 lands are reftored to fertility ; its ufe feems to me to confift 

 in expofing the roots of vegetables to decay, whereby food for 

 a frefli growth is prepared ; the atmofphere alfo depofites fixed 

 air and carbonaceous fubftance on earth long expofed to it. 



Draining is an operation equally necclTary and well known, 

 on which no more need be faid here. 



Vol. V. T Paring 



