No. 63.] ' 251 



it ? In Ihe first plac'se, the fermentation should be very gradual. 

 Make the heap in the shade, or on the north side of a building, and 

 manage it just as you would manage a coal-kiln. The more the air 

 is excluded, the slower and better will be the process. Now cover> 

 ing it with earth will have this effect; but vapor w^ill rise even when 

 it ferments slowly, and therefore marl may be freely scattered through 

 the heap as it is made; but no quick lime. Lime, indeed, should 

 form an outside covering for the whole pile (when marl is not at 

 hand,) but it should be carefully prevented from coming in contact 

 wuth stable manure or any animal matter. It must not touch them. 

 It spoils them. A layer of earth should be interposed, and then the 

 lime would be highly useful in catching and retaining the fertilizing 

 vapor as it rises. 



I believe there is no difference of opinion on this subject among che- 

 mists. Humphrey Davy speaks in the plainest language against mix- 

 ing quick lime with common dung as injurious; and other eminent 

 men fully accord with the doctrine. On the outside of the heap, 

 however, quick-lime in a few weeks would be carbonated, and after 

 undergoing this change it might be safely mixed with the compost. 

 A fresh coiit may then be applied. 



But some farmers may not wish to apply their barn-yard manure 

 in the spring, or make it into compost; they may perfer using it after 

 harvest, and yet not have it wasting in the mean time. In that case 

 I w^ould advise that it be thrown inward where it lies thin, just so far 

 that this work conjointly with the work of covering it, shall amount 

 to the least labor. Then cover the whole with straw or earth to pro- 

 tect it from the sun, and cause it to be trodden down by the cattle as 

 firmly as possible, to exclude the air and prevent fermentation. Some 

 of you may recollect when forking up such matters after harvest, that 

 the straw in spots was bright and unchanged. That was where it 

 was well trodden. All change is attended with loss; but as some 

 change may be expected, strew lime or marl and plaster plentifully 

 over it, to absorb or arrest the fertilizing vapor. 



The effect of plaster (composed of lime and sulphuric acid) has 

 long been a source of wonder; for it was a wonder how one bushel 

 could add more than twenty times its own weight to a crop of clo- 

 ver. Inquiring minds, of course, have been busy in trying to explain 

 the mystery; but I doubt if all the properties of this manure are un- 

 derstood even at this day. Humphrey Davy was inclined to think 

 that plaster was a necessary part of the woody fibre of some plants, 

 analagous to the bony matter in animal structures. The plant could 

 not do without it, though it wanted but little; and hence so small a 

 quantity had such a powerful effect. " Plants which seem most be- 

 nefited by its application," says that eminent chemist, " always af- 

 ford it on analysis." 



When this theory was announced some thirty years ago, it was re- 

 jected in this country, where the effects of plaster were much better 

 known than in England, but if he could have shown that it enters 

 into such plants in any definite proportion, some of the arguments 



