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The atmofphere is the grand magazine, the great 

 receptacle of putrid vapours, which are conftantly 

 exhaled and flying off from the furface of the earth, 

 and from the whole race of vegetables and animals 

 which fubfift upon it. Thefe putrid exhalations con- 

 ftitute the true genuine vegetable pabulum^ or food 

 of plants j therefore v/hatever fubftance of an abfor- 

 bent nature attracts thofe principles more power-: 

 fully than the foil it is laid on, will, to fuch land, 

 be a manure, and infallibly improve the fame. 



Thofe fubftances which are of a calcarious na- 

 ture, and can be burnt into lime, have their powers 

 as manures greatly improved thereby; provided 

 they are ufed fo as to impregnate the foil before 

 their virtue is diminilhed or impaired by being 

 expofed to the air. I^ime, of whatever fubftance 

 it is made, whether of ftone, chalk, or fhells, by 

 being expofed to air for a few days, expands and 

 falls into a fine powder, and thereby lofes its a(^ive 

 principles caufed by the fire, and becomes totally 

 effete and dead, poflefled precifely of the fame 

 virtues as the ftone, chalk, or fliells, of which it 

 was burnt, and no more. The difcovery therefore 

 of the true method of ufing lime, fo as to impreg- 

 nate the foil with its a6live principles, is a -very 

 great improvement in pradtical agriculture; for 

 before this was known, large fums of money were 



expended 



