On Gypsum. 117 



sions to chemical science, shall not venture an opinion. 

 It is worth remarking, however, that Fourcroy, in his enu- 

 meration of the uses of gypsum, although he pronounces 

 it" une des matieres les plus utiles que la nature produise," 

 takes no notice of its use as a manure, unquestionably its 

 most valuable and important quality, of which he must 

 have been either ignorant, or incredulous, for its value 

 of that kind, was known to the Germans, prior to the pub- 

 lication of his work. This omission, however, tends to 

 render his testimony more impartial and satisfactory. 



These facts, and the inferences derivable from them, are 

 so analogous to the many suggestions made by yourself 

 regarding the * modus operandi 9 of gypsum, that I thought 

 it would be personally acceptable to you to have them cor- 

 roborated by high chemical authority ; and let me add, that 

 I was led to investigate the subject, by the interest you ap- 

 peared to assign it, in -your many useful tracts on the va- 

 lue and uses of gypsum. I rely on your indulgence, for 

 every attempt, however feeble, to investigate the principles 

 or improve the practice of agriculture, as my apology for 

 offering these remarks. Such speculations cannot influ- 

 ence the opinions of a practical farmer, injuriously ; and a 

 thorough acquaintance with the means we employ, must, 

 as in all other sciences promote that of Agriculture. 

 With my wishes for the success of your Agricultural 



Society. 



I am your humble servant, 



Jno. Patterson. 



To Richard Peters, Esq. 



President of the Philad. Agric. Soc. 



