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On Plaisterof Paris: fo 
» Query, 9. What is the greatest product per acre of 
grass, &c. you have known by the means of plaister 2 
_ Answer. 1 cannot answer this query with certainty, 
having never weighed any. But by computation from 
land that has been manured ‘before it was plaistered, I 
have hadi from two crops of clover about four anda half 
tuns per acre; and from poor unmanured land, that I 
should not suppose would have produced, half atun, I 
have had frequently oneand an half, and perhaps two tuns. 
I propose trying'the experiment, by weighing a small 
proportion of a piece I have’ plaistered, and another 
sowed with. cloverat the same time, along side, and 
treated every way in the same manner, except the plais- 
tering. The plaistered, I think, will produce at the rate 
of two tuns; andthe other I do not beheve will produce 
at the rate of five hundred weight per acre. 
Query 10. Have you ever used it with other manure, 
and what ?—and the effect if any superior to the plais- 
ter alone ? | 
Answer. I have never found any kind of manure to 
be of any advantage to strengthen the plaister. I have 
put it on after lime and dung frequently, and_have al- 
ways found the greatest difference, in the, effect, where 
it has been put on entirely alone, both on clover and In- 
dian corn. Where the manure has been put the crop has 
been the greatest, but their operations I believe to be 
entirely independent of each other.* 
* Whether my idea of the sulphuric acid being the active 
agent, in the gyps was original, or adopted, I cannot tell ; nor do 
Iclaim merit on such accidental thoughts. But since my conjec- 
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