50 On Plaister of Paris. 
Query 5. Have you repeated the application of it 
with or without ploughing? at what intervals and with 
what «ffect ? ; é 
Answer. | have answered above; but I am inclined 
to think its effects will lessen by a frequent application, 
but not more so than the frequent application of any ~ 
other kind of manure. Perhaps the improvement of land 
may be something similar to that of animal improve- 
ment, which is better promoted by a change of nutri- 
ment, than by being confined to any one kind.* 
Query 6. In consequence do you find that it renders: 
the earth sterile after its useful effects are gone ? 
Answer. I have not observed any sterility yet to fol- 
low its use; perhapsa greater length of time may pro- 
duce such appearances. For some years past my rota- 
tion of crops and times of breaking up grass, has been 
as followeth : I have'seven fields; one with Indian corn, 
one in fallow that was in Indian corn the year before, 
one in winter grain that was a fallow the year before, 
four in grass. By which rotation 1 have always four for 
pasture or. mowing, besides the fallow and the wheat 
field from harvest the remainder of the grass season. 
* Mr. Sellers was of the opinion I have often avowed on 
this subject. He gave me numerous instances, in his long ex- 
perience, as to changes of both’plants and animals ; as well 
of individuals, as of locality and nutriment. He carried it into 
the change of mariure’; oi the benefit whereo! I have'seen 
many striking and undeniable proo.s. He was uncommonly 
observant ; and one ’ot'a strong mind, not destitute of cultiva- 
tion. R. P. 
September, 1810. 
