ON THE USE OF LIME, MARL, AND SHELL-SAND. 47 



lime, showing that it has been limed at no very remote period. 

 I also readily detected in it grey light-coloured stones, which 

 strongly effervesced with acid, and were evidently limestones, 

 probably lias or inferior oolite limestone. 



The soil from Mendip, a red-coloured soil likewise, appeared 

 to have been recently limed, for it is full of white particles and 

 lumps of slaked lime. The stones found in this soil were partly 

 red sandstones, partly greyish crystalline limestones, and a few 

 bits of crystalline calcspar ; both the sandstones and the lime- 

 stones effervesced strongly with acid. 



One of the soils from Street, Glastonbury (that marked #), is 

 a stiff dark-coloured soil, full of vegetable matter, and containing 

 also small stones and shells, which strongly effervesced with 

 acid. 



The second soil from Street, marked Z>, does not contain much 

 organic matter, but a good many small stones, which by their 

 effervescence with acid are proved to be limestones. 



Mr. Clark, who sent these soils, observes that the dark-coloured 

 soil is from a pasture that is tert (that is tart or sour), and 

 scours the cattle after Midsummer before frost sets in ; the red- 

 coloured soil, on the other hand, produces sound pasture ; when 

 cultivated it was formerly extensively limed. 



It has been supposed that the deficiency of lime in pasture 

 land was a cause of the production of sour herbage, or herb- 

 age that scours cattle. As I have not paid particular attention 

 to this subject, I cannot pretend to say much about it ; but this 

 is quite certain, that there is land, as in the case before us, which 

 contains as much as 12 per cent, of lime and yet produces grass 

 that scours cattle. The growth of sour grass and the soil from 

 Street cannot be connected with the proportion of lime it con- 

 tains. The dark-coloured appearance and the large quantity of 

 organic matter in this soil appears to me to indicate imperfect 

 drainage, and to this circumstance probably the production of 

 sour herbage is due. We have here another instance showing 

 that there may be an excess of organic matter in a soil although 

 it contain much lime. 



These four analyses are particularly interesting in showing the 

 utility of examining soils for lime before going to the expense 

 of applying lime to the land, for they present us with no less 

 than four instances in which the money laid out in the purchase 

 of lime has been spent to no good purpose. And this leads 

 me briefly to allude to the mode of ascertaining whether a soil 

 is likely or not to be benefited by lime. Put a small quan- 

 tity of soil in a tumbler, and pour upon it first a little water 

 and then a good deal of spirits of salt or muriatic acid ; if this 

 addition produces a strong efferyescence, there is no need of ap- 



