38 



MR. W. FAIRBAIRN ON THE 



Experiments to ascertain the amount of water absorbed 

 by various kinds of stone. 



•J 



Description 

 Stone. 



Sandstone. 



Grauwacke 

 Granite 



Grauwacke 



Locality. 



Weight 

 before im- 

 mersion. 



From the above table it will be observed that specimen 

 No. 15, the Ingleton grauwacke, is the least absorbent, and 

 No. 12, the Welsh grauwacke, absorbs almost as little, while 

 Nos. 9 and 14 of the sandstones absorb most. The granites, 

 though closely granulated, take up much more water than the 

 grauwackes, but less than the sandstones. The resistance of 

 the grauwacke specimens to the admission of water is four 

 times that of the granite, and thirty-six times that of sand- 

 stone, such as is found in the Yorkshire quarries. 



