ACTION OF SALTS. 105 



applied, as it is in England, at the rate of about a 

 cask to the rod, which will give about three per cent, 

 of lime in the soil. Even in this case no change is 

 produced, the soil is as unproductive as ever. The 

 experiment has failed, and is charged to book farm- 

 ing. 



160. The properties of lime, and geine, are here 

 to be remembered. Lime in excess, renders geine 

 insoluble, granting it to have been in a soluble state. 

 Lime changes vegetable fibre into soluble geine, but 

 being applied in excess it forms an insoluble salt. 

 Now by the supposition, there was no great excess of 

 vegetable matter, and the lime, rendering only a small 

 portion of that soluble, is itself then, always in ex- 

 cess, and though it converts, it at the same time 

 locks up that geine which it had converted. The 

 reasoning will hold good, whether a cask to the acre, 

 or a cask to the rod, has been applied. 



161. The lime has been perhaps, in a caustic 

 state, fresh from the kiln, and as soon as it falls into 

 powder it is spread and covered in. It is greedy of 

 carbonic acid, so long as it remains caustic, it ab- 

 sorbs this gas, and slowly becomes carbonate of 

 lime. It is now like shell marl, clam, oyster and 

 muscle shells. The mode of reasoning applies to 

 all these forms. Slowly, but surely, it may not be 



