On plaster of Paris, 181 



enable our American fanners to surmount many of their 

 greatest a{)parent difficulties, — and what is not less im- 

 portant, to discard their absurd and pernicious prejudices. 



With the highest respect, 



Wm. DarlingtoNo 

 Hon, Judge Peters, 



Belmont, June ^^th, 1824. 

 Dear Sir, 



I THANK you very much for your attention to my 

 request, in relation to the practice of applying plaster of 

 Paris. Being an Octogenarian^ I have considerably in- 

 termitted, but can never abandon, my desire to promote 

 the leading interest of my country. I despise adhering 

 to an old opinion, (or any opinion) merely because I had 

 promulgated it. But when long convinced of its sound- 

 ness, I do not lightly banish it. In my first trials, and 

 in the little tract I published, I entertained the same sen- 

 timents respecting it, I now hold ; — to wit, that after it 

 had exhausted ihe inert vegetable matter it finds in the 

 earth, a new supply either of vegetable, or animal, sub- 

 stances must be afforded. Neither plaster, /jer .se, nor 

 lime, is manure. I(s composition is well known ; and 

 the greatest propr^rtion is sulphuric acid; which sets 

 into activity, the substances proper for its operation. 

 Sir H. Da\ v's notion, ihi?t it operated on plants, or in 

 the earth, only where gypsum vvas found, I never did 

 ac^ree in ; much as I adnriire his chemical science. Nor 

 do I consider his trifling experiments on a plateful of 

 minced veal, a svifficient refutation of my long expe» 

 rience, that it will decompose both animal and vegetable 

 substances. See our 3d vol. p. 296. 235, &c. 



