190 0W MANURES. 



Good effects the ashes of vegetables, and of earths, will account for & 

 countedfor." certain degree of benefit resulting from their use; but per- 

 haps it does not fully account for the enormous crops, which 

 are gained by the operation of paring and burning. I have 

 gone through not an inconsiderable course of reading, with 

 a view to discover the theory of this fact ; but my research 

 has nop entirely satisfied me. The formation of charcoal, 

 sulphate of potash, and phosphate of lime, with the decom- 

 position of water, and the oxigenation of clay, added to 

 the mechanical change effected by the fire, may certainly 

 account for a considerable part of the improvement. 



3. The Paring and the Burning. 



Method of The common practice is to pare from two inches on peat 



•Deration. 5 ** sm ' s to na ^ an mcn on others: an inch is the more general 

 depth. 



Mr. Wilkes, of Derbyshire, has ploughed nine inches 

 deep, and burnt the whole furrow with the assistance of 

 co&\ sleek; manuring double the quantity of land burnt, 

 but working an immense improvement on the space thus 

 deeply burnt. I have seen other cases in which four inches 

 depth was burnt with great success. In the fens of Cam- 

 bridgeshire the paring is done with a plough, and tke depth 

 from one inch to two. On sand the paring should be as 

 shallow as possible. 



The chief attention paid in burning is to guard against 

 too great a calcination ; as the general opinion of those who 

 have most practised this husbandry is, that the turfs should 

 be rather scorched or charred than reduced to ashes. If 

 burned during a brisk wind, sands frequently vitrify, and 

 will not afterwards in many years, if ever, be restored to a 

 state capable of contributing any thing to the support of 

 Vegetables: hence it is a practice with those who are aware 

 of it, prior to burning, to shake out, in dry weather, from 

 the grass-roots, the greatest part of their substance with 

 barrows. The heaps should always be small, and the fire 

 be applied on the sheltered side of them : this method, in a 

 degree, should be regarded in the burning of earths of al- 

 most 



