[ 46 ] 



Answers to Queries on Plai^ter of Paris ^ by John Sellers^ 

 Esq, of Derby Township, Delaware County, 



August 1 5th, 1796. 



Dear Friend, 



It would afford me much pleasure to have it in my 

 power to communicate any observations generally use- 

 ful on the subject of thine of the 19th of last month, to 

 which the obliging thee would be an addition. The 

 analysis thee mentions in an English work I consider as 

 a useless inquiry, until we w^ere able to know with the 

 same certainty all the properties of plants, and the por- 

 tions of the variety of elementary foods nescessary for 

 the greatest promotion of vegetation. I therefore should 

 suppose acids friendly or unfriendly, according to the 

 quantity of the other kinds and portions of manure ap- 

 plied therewith, as we know a due quantity of lime is 

 friendly, and that too much is entirely destructive to 

 vegetation, and that a greater quantity may with safety 

 be applied with dung than without it. The knowledge 

 most to be depended on, is to apply such manures as 

 from experience we find best to promote vegetation. 

 I have thought a repetition of the same sort of manure 

 on the same ground would not have so good an effect as 

 a change, which perhaps may be as necessary as that 

 of different kinds of grain, flax, potatoes, &c. 



My first use of plaister was in the year 1786, on 

 land limed about fifteen years before, and afterwards 

 manured with dung in a moderate degree. It was at 

 that time sown with clover on the wheat in the spring. 



