On Plaister of Paris. S3 



Q:uery 11. Its duration ? 



Answer. When it throws up gentle and moderate 

 crops, its efficacy is of the longest duration. If it is vio- 

 lent in its first operation, it is of short continuance. I 

 have known it exhaust itself in one year. But I have 

 had benefit from one dressing of three or four bushels 

 to the acre, for five or six years, gradually decreasing 

 in its powers. I prolong the efficiency of dung, by 

 plaistering the second or third year, when the clover, 

 on dunged or any other ground, begins to fail. Perhaps 

 the scattering it annually, or every other year, in small 

 portions, will continue for a length of time gentle ope- 

 rations, and prevent violent effiDrts. I have heard of 

 some who have practised sowing it frequently, and in 

 small quantities, and obtained good crops of grass for 

 twelve years and upwards. 



The weeds of our fields, /^/2>^ which have been at former 

 periods under bad culture, forbid their laying in grass, 



(^A jThe Japanese^ as well as the Chinese^ reject the dung of 

 horses and cattle, because they contain the seeds of weeds, and 

 use night soil, which their laws compel them, to save. '^ Their 

 fields are for this reason, (among others) so free from weeds, 

 that a celebrated botanist, passing lately through Japan, with 

 the Dutch embassy, could scarcely find any other plants 

 on the corn fields, but the corn itself." Ingenhausz y^^c?^ of 

 plantSy page 15. If what has been quoted on this subject will 

 have no other effect on our practice, it ought to warn us to 

 be more careful in rotting or composting our dung of horses, 

 &c. and to prevent the seeds of weeds mixing with our manure. 

 Nothing in this country is in so miserable a stile as the mis- 

 management (with some exceptions) of our stercoraries. The 



