[ '9^ ] 



It is well known that clays and loams are rather hardened 

 than confumed by heat. However, unlefs frefli feeds be com- 

 mitted, the foil will be unprodudive for a number of years ; 

 the coaly principle may alfo be exhaufted by too many 

 crops. 



Of Gypfum. ' ' 



This manure was difcovered by Mr. Mayer, a German 

 clergyman of uncommon merit, in the year 1768; it has 

 fmce been applied with fignal fuccefs in Germany, Switzerland, 

 France and America. If in England it has not been fo much 

 approved of, it muft be becaufe the calcareous principle prevails 

 there almoft univerfally ; clayey lands are moft improved by it ; 

 the time for fpreading it is February or March, and then it is 

 to be thinly ftrewed on the land at the rate of about eight 

 bufliels to the acre ; more would be hurtful ; the rationale of 

 its efteds may be deduced from its extraordinary feptic power, 

 for it is found to accelerate putrefadion in a higher degree 

 than any other fubftance *; and hence it is not ploughed in 

 like other manures, but barely ftrewed on the furface of the 

 land, and in the month of February, to convert the old grafs 

 quickly into coal to nourifh the young growth. 



2dly. From its being itfelf no inconfiderable part of the food 

 of many plants, particularly of clover, pulfe and corn, byt the 

 land on which it is ftrewed muft be dry, fuch as would naturally 

 fuit clover, &c. otherwife it would be ufelefs. 



Thus 



» Hlfloirc de la Putrsfaftion, 36. 



