98 



The distinctions derived from the touch, or 

 the feel, in rocks, are so limited, that it is unne- 

 cessary to consider them in this place. 



Those derived from odour, are nearly of equal 

 inutility ; although the argillaceous smell has been 

 often enumerated as a distinction. It belongs to 

 so many different rocks as to form no criterion in 

 itself; and is so generally accompanied by other 

 characters of greater distinctness, as to be rendered 

 unnecessary even when present. 



The property of absorbing water with rapi- 

 dity, appears, in the same way, to be a character 

 of little or no practical use, and no further notice 

 is therefore taken of it. 



