On Lime and Marls, 205 



" knows that the soil is soon exhausted, and rendered 

 " incapable of supporting any kind of vegetation.'^ 

 Here, in my opinion, the terms calcareous substances 

 are too general and i^ague ; for, though some calcare- 

 ous substances are known to be powerful solvents, 

 others perhaps possess nothing of that quality at all, 

 or at least in a very inferior degree. We know that 

 from 25 to 50 or 60 bushels of our best lime is a suffi- 

 cient dressing for an acre of land ; according to the 

 poverty or richness of the soil, at the time it is ap- 

 plied ; whereas Dr. Anderson says he has had expe- 

 rience of lime in all proportions ; from one hundred, 

 to seven hundred bushels to the acre, upon a great va- 

 riety of soils ; and has always found that its effects in 

 promoting the fertility of the soil, have been in pro- 

 portion to the quantity employed, other circumstances 

 being alike. 



From these, and other cases which might be enu- 

 merated, would it not be a natural conclusion to sup- 

 pose that our strong lime acts by its solvent quality, 

 in dissolving or decomposing such soluble substances 

 as they meet with in the soil ? We find, when too great 

 a quantity is applied, especially if the land is poor, in- 

 stead of benefiting, it is often hurtful to the crop ; but 

 when applied in proper proportions, and with a judi- 

 cious rotation of crops, it is a most valuable manure \ 

 whereas Dr. Anderson's lime, of which too great a 

 quantity could not be employed, must have possessed 

 very little, if any, solvent quality, and its fertilizing 

 powers must arise from a nutritious principle. And 

 this agrees with the account of the mild lime, which 

 my friend, Joh;i Mills, of Chester county, put upon 



