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Plaster^ t?i moderate quantities^ assists in the putrefac- 

 tion of animal and vegetable substances. 



Read December 14, 1813. 



Belmont, November 21 , 1813. 



Dear Sir, 



I do not wish to prolong a discussion of a specula- 

 tive nature, for any objects I have in the establishment 

 of an opinion. But, in the hasty observations (made 

 while the press was waiting) on Sir H. Davy's conjec- 

 ture on the causes of operation of the gypsum ; it es- 

 caped my recollection to mention a recent fact on the 

 subject. The use I should then have made of it, would 

 have been to show, that small and contracted experi- 

 ments, made, in relation to agricultural facts, in the 

 laboratory of a chemist, (however eminent and truly 

 respectable he may be,) are not competent to establish 

 a general principle ; though no one can hold in higher 

 estimation than I do, the aid chemistry is capable of 

 affording to agriculture. Nor do I mean to say, that 

 uncommon instances occurring in the fields of a prac- 

 tical farmer, are to be deemed decisive. Mr. Davy 

 grounds his opinion relative to the plaster, being, or 

 not, a septic; on an experiment he tried on minced veal, 

 mixed with the gypsum. He found it had no effect in 

 putrefying the meat ; and concludes against its septic 

 qualities. Not wishing to load the subject with instan- 

 ces of practical proofs, failing under my own observa- 

 tion, and that of others ; which would show that the 

 contrary conclusion (without venturing to pronounce 



