228 On well-rotted Diing^ Stercorariesy &?(?, 



■ " ' - ' ■ — ^ 



the offils of Indian corn. He cuts off the whole stalk 

 (as many of us do, and all ought,) and uses it for litter. 

 He does not intermix the cobs among his muck. These 

 I always rot down in the stercorary. He strews plaster 

 on his muck, before it is ploughed in ; — than which 

 nothing more efficaciously promotes putrefaction.* See 



* Theories are unimportant, when compared with facts. An 

 able chemist and mineralogist alleges, that an experknent had been 

 made here to test the conjecture 1 hazarded, in my compilation on 

 Plaster, that the sulphuric acid was the cause of operation in the 

 Gypsum. The experimenter had found no reason to believe my 

 conjecture to be correct. He, therefore, concludes my idea to 

 be unsound, and unsupported. He substitutes another conjecture 

 in place of mine ; i. e. that it operates as a " sefitic to dead fibres ; 

 and a stimulus to living' ones'* On subjects merely chemical I 

 enter not the lists with chemists. The fields of the farmer are 

 far the best expositors. On these I have tried many experiments, 

 on scales both small and exlensive, with a view to my theory. In 

 some I have failed ; but have so often succeeded, that the ballance 

 has fixed my opinion. Still subject to the controul of more able 

 experimenters. Plaster is good or bad according to the proportion 

 of the sulphuric acid, or oil of vitriol, in its composition. Forty 

 eight parts in a hundred, are the proportionate quantities in the 

 best plaster. It operates v/ilh less of this acid. But it requires 

 more in bulk, or total, of the matter containing the acid, according- 

 ly as the requisite proportion is deficient. The acid has been de- 

 tached, and the earth, Sec. in which it had been detained, strewed ; 

 without the least agricultural effect. To produce any important 

 effect, an enormous quantity of this earth would be required. 



It is far from my intention to enter into controversy ; or to hold 

 out pretensions to chymical acquirements. I think, that causes of 

 operation, however desirable the knowledge of them may be, are, 

 most commonly, subjects of mere conjecture ; as I still (however 

 confident I may appear) continue to consider the one assigned by 

 me. Probably, having assigned it, I may have yielded to a bias 



