202 ON THE COMPOSITION OF SOILS, &C. 



*' mere poverty of a soil is not a criterion where- 

 " by we can judge j we must consider what hath 

 *' made it poor. If it is naturally so, we may 

 •' almost infallibly conclude that it will become 

 '* better by being manured with lime. If it is 

 *' artificially poor, or exhausted by continual 

 " cropping, we may conclude that lime will en- 

 *' tirely destroy it. We apprehend that it is this 

 " natural kind of poverty only, which Mr. An- 

 •' derson says in his Essays on Agriculture, may 

 " be remedied by lime ; for we can scarce think 

 *' that experience would direct any person to 

 " put lime upon land already exhausted. His 

 " words are, * Calcareous matters act as power- 

 *' fully upon land that is naturally poor, as upon 

 '* land that is more richly impregnated with 

 " those substances that tend to produce a 

 " luxuriant vegetation. Writers on agriculture 

 *' have long been in the custom of dividing ma- 

 " nures into two classes; viz. ewric/wVz^ manures, 

 " or those that tended directly to render the 

 " soil more prolific, however sterile it may be; 

 " among the foremost of which was dung : 

 *' excit'mg manures, or those that were supposed 

 '* to have a tendency to render the soil more 

 ** prolific^ merely by acting upon those enriching 

 *' manures that had been formerly in the soil, 

 " and giving them a new stimulus, so as to en^* 



