On Plaister of Paris. 57 



as tiic ^Teatest efFtct of the plaister is discoverable upon 

 clover.^ 



Your most obedient, 



Humble servant, 



Edward Duffield. 

 Benjield, August I6th, 1796. 



The Hon. Richard Peters, Esq. 



* I was gratified by Mr. D's agreeing in an opinion I had 

 long held, and frequently mentioned to many others. I had 

 conversations with Mr. D. since this answer. He, with me, 

 tried many experiments with the view to th s theory ; and 

 both were confirmed in it : though he, as well as mysel ', were 

 not reckoned orthodox^ by chemical savans. They insisted 

 that the gyps was an insoluble compound, and that the acid 

 must be first disengaged (which no doubt it is) before it can 

 act. R. P. 



September 1810. 



H 



