ON GEOLOGICAL TIME. 43 



of 8 to the square of 7, that is, in the ratio 

 of 64 to 49. There must have then been more 

 centrifugal force at the equator due to rotation than 

 now in the proportion of 64 to 49. What does the 

 theory of geologists say to that ? There is just now 

 at the equator one two-hundred-and-eighty-ninth 

 part of the force of gravity relieved by centri- 

 fugal force. If the earth rotated seventeen times 

 faster bodies would fly off at the equator. The 

 present figure of the earth agrees closely with the 

 supposition of its having been all fluid not many 

 million years ago. 



20. The centrifugal force a hundred million 

 years ago would be greater by about 3 per cent, 

 than it is now, according to the preceding estimate 

 of tidal retardation ; and nothing we know re- 

 garding the figure of the earth, and the disposition 

 of land and water, would justify us in saying 

 that a body consolidated when there was more 

 centrifugal force by 3 per cent, than now might 

 not now be in all respects like the earth, so far 

 as we know it at present. But if you go back 

 to ten thousand million years ago which does 



