COMPARATIVE VALUE OF VARIOUS KINDS OF STONE. 39 



On comparing the results of the experiments on the York- 

 shire sandstones, it will be seen that the difference of resist- 

 ance to pressure does not arise so much from the variable 

 character of the stone in different quarries, as from the posi- 

 tion in which it is placed as regards its laminated surface, 

 the difference being as 10:8 in favour of the stone being 

 crushed upon its bed to the same when crushed in the line of 

 cleavage ; the same may be said of the limestones. 



Comparing the strengths indicated by the above experi- 

 ments, I find a very close approximation in the granites, but 

 considerable difference in the Yorkshire sandstones. Mr. 

 Uennie obtained his specimens from the same district, the 

 valley of the Aire ; but the force required to crush the Brom- 



* Pressure applied in the direction of the cleavage, 

 t Pressure applied perpendicularly on the bed of the stone. 



