74 On Plaister of Paris, 



Query 4. What soils are the most proper for this ma- 

 nure. 



Answer, Li,^ht soils, dry and sandy, or loamy. On 

 clay I never succeed, though I have heard of its being 

 used on clay with a degree of success. /^6>/ On vv^et soils 

 I have always failed. I have strewed it on mossy swamps. 

 On elevated spots in these swamps, it has killed the 

 moss and thrown up white clover wonderfully; but has 

 done nothing where the water around these spots con- 



f^^JWhene it has any success on clay, it is rare. The Presi- 

 dent (whose lands at Mount Vernon and in its neighbourhood, 

 are generally strong clay, or inclining thereto,) has frequently 

 told me, that he has always been unsuccessful with plaister, 

 I think he has tried it from one as far as twenty bushels t» 

 the acre, without any kind of benefit. That I might be accu- 

 rate in this account, at my request, he was pleased to inform 

 me, that he had " tried the plaister of Paris on his land 

 (which is stiff and cold) at die rate of from one to twenty 

 bushels to the acre. — It has been spread on grass and plough- 

 ed land. — On the latter it has been ploughed in ; — harrow- 

 ed in with a common tined harrow ; bush harrow ; — and not 

 harrowed at all. The effects in either and all the cases, were 

 not more than if he had taken up as many bushels of the same 

 earth and scattered them again over the surface of the ground. 

 Yet he beUeves inland is a friend to gypsum as a manure*^ 



wards, by the extraordinary verdure of the grass (chiefly 

 white clover) which grew spontaneously on it.^ 



* This experiment Is alluded to ui jny coimniuiication on salt. 2 vol. Memoii-s. 173, But by a 

 typographical enror, pounds are inserted for husMs. I went as far as 20 bushelsjto the acre, (or ift 

 that proportion) most uselessly and injurious!)-. R- P- 



September, 1810. 



