THE POSITION OF THE BARTERS AXIS. 119 



Taking the weight given by Airy to shift the axis two 

 or three miles, we find it is about half the weight of Europe, 

 if we take its average height as 1343 feet. 



Now, supposing we could remove a weight equal to that 

 of Asia, 1 000 feet high, from the centre of a land-hemisphere 

 about 45° N., and add a similar weight at the antipodes in 

 a sinking Pacific Ocean, leaving the remaining portions in 

 each hemisphere balanced by the natural configuration, we 

 should then have an alteration of from 18 to 27 miles. It 

 is true that at the rate of denudation by solution that has 

 been used for calculation, it would take to remove so great 

 a thickness as that taken about 1 7 million years ; but we 

 shall see that there are other causes which may very much 

 reduce the time required ; and the vast thickness of calca- 

 reous rocks, which are only the record of others from which 

 they were partly formed, shows how many times such areas 

 must have been transported from land to sea. And it must 

 not be forgotten that the configuration may have been more 

 favourable, though the present allows us to demonstrate 

 that this may be a disturbing cause, and that there will be 

 a tendency for the oceanic half of the globe to gain weight 

 over the land-hemisphere. Having examined our first ex- 

 ternal cause, we turn to the displacement of the water. 

 The sinking of an area equal to the continent of Asia to 

 the mean depth of the ocean would bring a weight of 

 water sufficient, if the antipodes were a suboceanic rising 

 area, to displace the position of the axis 40-60 miles. 



I may here say that the amount of change I have sup- 

 posed is not more than has taken place since the beginning 

 of the Miocene period, though of course not in the manner 

 put ; and we see that at present, while land-areas, as part of 



vation- to the submergence-area on one side, and the opposite points from the 

 submergence- to the elevation-area, so that land antipodal to land, and water 

 to water, is the consequence. 



