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diffolved the dried refiduum in muriatic acid, an oily matter floated 

 on the furface of the liquor. 



F:ioM thefe experiments I have ventured to affert, that the co- 

 louring matter is compofed, in proportions which I have not been 

 able to afcertain, of a mixture of bitumen and carbon. 



With refped to the azot I am unable to form any fatisfadory 

 conjedures cf its origin. IVlight it not have proceeded from the 

 body of the animal whofe fliell had contributed the carbonate of 

 lime to the formation of the mafs? 



The following fads may affift enquiries upon this fubjed: 



Calp is found in great quantities in the neighbourhood of 

 Lucar ; and the quarries from which it is dug generally exhibit 

 tlie following appearance : 



Imjsiediately under the vegetable mould is a thin bed of lime- 

 flOj^ gravel ; beneath which, to a confiderable depth, are flrata 

 ofda^k iime-ftone, feparated from each other by beds or layers of 

 argillaceous fliiftus. The deeper the quarry is dug, the nearer 

 the lime-flone feems to approach to the nature of calp ; to which 

 it at length arrives, by a gradual and fcarcely perceptible tranfition. 



In the grounds of Edmondfbury, fcarcely one mile from Lucan, 

 there is a fpring, called by the common people the Boiling Well, 



which 



