Features of the Earth's Surface. 351 - 
earth as a whole is certainly more rigid than a globe of solid glass, 
and probably more rigid than a solid globe of stel.* We have 
already shown how fatally this extreme rigidity operates on 
any theory which attributes the inequalities of the earth’s sur- 
face to bendings of a solid crust. 
- Very recently my attention has been directed by my 
brother, Prof. John LeUonte, to another fact bearing strongly 
in the same direction, viz: the form of the equatorial section of 
the earth. If the earth were an exact spheroid of revolution, 
There is, as far as we know, but one argument of a general 
nature, which has recently been brought forward in favor of 
the interior liquidity of the earth, viz: the three laws of earth- 
quake occurrence rendered probable by Alexis Perry. The 
laws are as follows: 
n 
to follow the law of fides. Many geologists seem to think that 
* Phil. Trans., May, 1862. Thomson & Tait, Nat. Phil., p. 689. 
t Cosmos, vol. iv, p. 19, Sabine’s edition. 
