On Plaister of Paris. 73t 



tion whether any increase of quantity will extend the 

 effects. ^«y^ 



CaJ On the principle that gyps is a salt, [vide note r ] aid 

 salts check fermentation when applied in too great quantities^ 

 it may be presumed, that the requisite quantity o! plaister, is 

 regulated by the fermentable putreiying substances it finds in 

 the earth on which it is strewed. It these be scarce, a great 

 quantity of plaister, beyond what is necessary to operate with 

 them, is hurtful. I remember to have sowed, on a strip 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 nothings till I dunged the field for wheats two 

 or three seasons after the over dose of plaister, I was surpris- 

 ed by this small strip recovering itself, and remaining for 

 years superior to any other part of the field. Yet I have 

 heard of ten bushels to the acre, being strewed to good effect.* 

 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 

 3n 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 of 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 of this experiment at hand, but I think the wheat 

 dwindled with eight bushels to the acre, and nothing grew 

 ^fter, 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 after- \ 



* On inquiiy I found tliis was a iXUStoJ^ Jl» P« 



.Septanber, 1810. 



