LIME. 407 



taining carbon dioxide acting through unnumbered ages 

 has formed caves and underground channels in which 

 the water runs. The Derbyshire caves are examples of 

 the former, while underground rivers are one of the 

 peculiar features of this formation in every region where 

 it occurs " (Primrose McConnell's Agricultural Geology). 



Carbonate of lime, which is the chief constituent of lime- 

 stone, chalk and other calcareous rocks, is practically 

 insoluble in pure water, but readily dissolves in water that 

 contains carbonic acid gas. Consequently, such water has 

 a well-marked corroding action on these rocks. The at- 

 mosphere always contains a certain amount of carbonic 

 acid gas (carbon dioxide), which is the gas that issues 

 from a freshly opened soda-water bottle, and which is 

 very soluble in water. 



It is probable that the great porosity of limestone soil 

 is the reason why heavy cart horses which are bred on it, 

 very seldom retain their typical size and weight, which fact 

 was first ' brought to my notice, on observing that Shire 

 horses bred on the chalk soil of the Western portion of 

 Norfolk, were smaller, hghter and more active than their 

 Midland relatives. 



As far as I can learn, the soil of all districts in which 

 good saddle horses are bred, contain a large supply of lime, 

 as for instance in Ireland, the greater portion of which is 

 covered by Mountain Limestone. " In Kentucky, the 

 secret of the marvellous success of breeders of the past 

 lies alone in the soil and grasses. There is not the shadow 

 of a doubt that the underlying limestone and the succulent 

 blue grass are responsible for the great horses that 

 have come from this favoured section ' ' (Kentucky Stock 

 Farm). 



Lime to be efficient as a food for grass, should be in the 

 surface soil and not in the subsoil, from which it cannot, 

 as a rule, rise to the top, as the action of the dissolving water 

 is to carry it more or less downwards. " It is only in the 

 extreme North of England, in Durham, where we find a 



