104 F\ REPORT OF PB0GRESS. E. W. CLAYPOLE. 



supplies no new argument against the position now taken 

 by most agricultural chemists that lime is a stimulant, and 

 not an enricher of the soil. If the soil contains nutritive 

 material the lime can render that material more readily 

 available ; and in this way it is advantageous to land where 

 stores of plant-food are locked up. But if the land con- 

 tains no such store the addition of lime can never bring- 

 forth any. Limestone soils are as much improved by the 

 addition of lime as are the shaly soils, whether black or 

 red, because the lime applied is in a very different chemical 

 condition from that which naturally exists there. The un- 

 burnt lime of the soil is quite inert as a decomposer of 

 plant-food ; but when burnt and rendered caustic its decom- 

 posing energy is developed. In the stone the lime is com- 

 bined with carbonic acid, which completely masks the active 

 property on which its value as a stimulant to the soil de- 

 pends. But in the kiln this carbonic acid is driven off, the 

 stone loses about half its weight, and its power of decom- 

 posing organic matter is developed. 



For the same reason a limestone soil, as it is called, if it 

 really contains any lime, coutains it in the same form, the 

 carbonate. Hence the lime, if naturally present in the soil, 

 is of no value as a stimulant ; it is inert ; and the addition 

 of quick or caustic lime has exactly the same effect both in 

 nature and amount as on any other land. 



The secret of the value of lime in agriculture lies in the 

 chemical fact already alluded to, that quick or caustic lime 

 has the power of decomposing animal and vegetable matter. 

 Hence lime in this caustic state speedily destroys organic 

 material and reduces it to a condition in which it is avail- 

 able for plant-food. But it is obvious that the amount of 

 plant-food thus produced will depend on the amount of or- 

 ganic matter existing naturally in every soil, and unless 

 this store is in some way replenished it must before long 

 become exhausted. 



The liming of land therefore year after year without the 

 application of manure of some kind must end in the reduc- 

 tion of the natural store of plant-food below that which 

 will yield a paying crop, as is the case with not a little of the 



