C 208 3 
burned plaister, and even quicklime pulverized an¬ 
swer the most beneficial purposes as manures on 
clay grounds ? I have made several trials of these 
but as my situation in life has not hitherto been 
such, as to allov/ me to make experiments either so 
accurate or extensive as is necessary to a complete 
knowledge of the subject; I forbear to particular¬ 
ize them at present ; and most cheerfully submit 
it to the consideration of those whose abilities and 
conveniencies enable them to determine it with ac¬ 
curacy and advantage to the public. 
With sentiments of respectful esteem, and wish¬ 
es for the promotion of the highly commendable 
objects of your institution, 
I am, gentlemen, 
Your friend and fellow-citizen, 
NATHANIEL CROOKSHANK, 
P. So It is thought by many tp be owing to the 
poverty of the soil, that clay grounds produce such 
poor crops as are often experienced ; but I feel 
confident in asserting, that poverty forms no part of 
the characteristics of them. For 1 have often seen 
hard clay, thrown out of the bottom of cellars, 
v/ells, after exposure to a winter’s frost, pro¬ 
duce hemp and other vegetables of extraordinary 
size ; and in one instance I observed like effects on 
a place where some pine logs had been burned, on 
clay recently thrown out of a well eight or ten feet 
deep, and all without the addition of any manure 
