“"% 
On Plaister of Paris. 78 
Eee 
tion whether any increase of quantity will extend the 
effects. (a) 
(a) On the principle that gyps is a salt, [vide note r.] and. 
salts check fermentation when applied in too great quantities, 
it may be presumed, that-the requisite quantity of plaister, is 
regulated by the fermentable putreiying substances it finds in 
the earth on which it is strewed. Ii these be scarce, a great 
quantity of plaister, beyond what is necessary to operate with 
them, is hurtful. I remember to have sowed, on astrip across 
a field, some years ago, a great dressing of plaister ; perhaps 
in the proportion of ten bushels to the acre. This strip pro 
duced little or nothing, till I dunged the field for wheat, twe 
or three seasons after the over dose of plaister. I was surpris- 
ed by this small strip recovering itseli, and remaining tor 
years superior to any other part of the field. Yet I have 
heard of ten bushels to the acre, being strewed to good «ffect.* 
But I know not the state of the ground, as to the pabulum 
for the gyps. I never found it beneficial, to sow the plaister 
in any such quantity. 
I, many years ago, divided half an acre of ground into 
square perches, to try the effects of common salt. I began 
by scattering a proportion o/ two bushels of salt to the acre, 
increasing the quantity on every perch. I numbered the di- 
visions, and kept an account of salt sown, and the produce 
of wheat with which the whole was sowed. I have not the me- 
morandum o/ this experiment at hand, but [ think the wheat | 
dwindled with eight bushels to the acre, and nothing grew — 
after, I believe, the proportion of twelve bushels of salt. I 
mention it now, because it seems analogous to the present 
subject; for I recovered the ground by moderate dunging. 
The spot salted might be perceived for many years aiter- 
q 
* On inquiry I found this was 2 mistake. R. P. 
September, 1810. 
