32 A PRACTICAL TREATISE 



the heap, and there can be little doubt that this discharg-e of 

 vapour and Huid will, if permitted, occasion the loss of some 

 portion of the virtues of the manure ; in order to guard against 

 which, a thin coat, of the same kind as the sides, and made as 

 fine as possible, is laid regularly and lig-htly over it, so that its 

 weig-ht may press equally and not heavily — for, if left in 

 lumps, their cumbrous weight would force the dung into holes, 

 and prevent its regular fermentation. 



By this covering of the dung with a due proportion of earth, 

 or of other coating, that loss is, however, in a great measure 

 prevented ; and the bringing of the heap into a state of prepa- 

 ration either sooner or later, as circumstances may require its 

 application to the land, can be effected by the denseness and 

 compression of the covering. The operation therefore requires 

 considerable delicacy; for, if dung, already in an unfermented 

 state, be so closely pressed as to effectually exclude the air, it 

 will be found, perhaps at the distance of several months, in a 

 state very little different from that in which it was put up ; or, 

 when it is thought to be in a perfect state of preparation, it 

 will, upon examination, be discovered to be only decayed, and, 

 instead of abounding in rich mucilaginous substance, to con- 

 sist almost entirely of mere vegetable earth. 



This also leads us to remark on the common practice of 

 driving carts, with their loads, iipon the dunghills ; the con- 

 sequence of which is that, as nearly the same road is followed 

 by each cart in crossing them, it is not possible to draw load 

 after load upon such a heap without compressing tliose parts 

 where the horses tread, and thus, instead of the dung under- 

 going a regular fermentation, which every part necessarily 

 would if it had been thrown loosely on the heap, and of one 

 uniform thickness, it is, in some spots, consolidated into a mass 

 which, iji most instances, greatly retards, and in some entirely 

 prevents, the process ; ' becomes mouldy, from want of air, 

 caloric, and moisture, — acquires a musty, turbid smell, — gene- 

 rates fungi, — and is, in that state, injurious to vegetation.' 

 The system has indeed been defended by some very able men, 

 one of whom insists ' that the dung should be drawn out of tJie 

 yards, and placed upon the bottoms, tliough not in the usual 

 way of throwing it up loosely, to cause fermentation, but, on 

 the contrary, by drawing the carts, with their loads, upon the 

 heaps, for the purpose of compressing tlie dung, and thereby 

 -preventing fermentation;'' and another conceives tliat 'a 

 positive benefit will be gained by this slight compression.' 



