THE STRENGTH OF THE EARTH'S CRUST 741 



to the isostatic compensation. In order to have the larger rehef 

 and its compensation fitted to a crust strongest in its upper part 

 and shading into a zone of weakness, the zone of compensation 

 should die out with depth and lie mostly in the upper half of the 

 zone of strength, since the stress-differences would die out at a 

 depth greater than the disappearance of the compensation. This 

 conclusion is seen to be in closer accord with several other lines of 

 evidence which have been noted than is the contrary assumption 

 of uniform compensation. 



{To he continued] 



