86 On Plaister of Park. 



my endeavours at their complete destruction. I have 

 obtained temporary victories over them, but have yet 

 to combat their ravages. I know of none in the pesti- ' 

 ferous catalogue, so exhausting and destructive as the 

 St. John's Wort. Besides its being injurious to cattle 

 and other stock, it is the greatest enemy the clover hus- 

 bandry has to contend with. Plaister will, by forward- 

 ing the red and white clover, and other grasses, over- 

 power many weeds ; but it has little, if any effect on 

 the St. John's Wort, or ransted. 



Query 12* Is there any difference between the Ame- 

 rican and European plaister ? 



Answer. I have in general found the European plais- 

 ter the best. But I have used the Nova Scotia (the 

 only American plaister I am acquainted with) to equal 

 advantage. I know not whether there has been any 

 chemical analysis of these plaisters, to enable us to 

 judge of their relative qualities. The quarries in Nova 

 Scotia may turn out better the more they are worked 

 and explored. There is a variety in the American plais- 

 ter, some being much better than others.^ 



* The Nova Scotia plaister I have used for many years, t 

 find it equal to any imported from Europe. I have seen 

 very little plaister from Europe of late years ; as that from 

 Nova Scotia answers all agricultural purposes pertectly. And 

 I believe all other uses, R. P. 



September^ 1810. 



