OF THE EARTH'S AXIS OF FIGURE. 45 



main identical while the denudations which gave rise to them have 

 undergone a complete change. In fact, unless there is some reason 

 to believe that throughout the whole of these successive epochs 

 there has been some predominating cause tending to accumulate, in 

 some one particular direction, all this infinity of minute changes, 

 there is no ground for believing that denudation is actually 

 capable of producing the desired effect. 



27. This conclusion seems to come out very plainly as the final 

 result of the reasoning expounded in the present paper. It is not 

 indeed an actual determinate answer like that which can be returned 

 to the question in art. 1. But it is, perhaps, as distinct an answer 

 as, all circumstances considered, could be fairly expected*. 



Discussion. 



Mr. Evans was willing to admit that in his Address he had 

 somewhat overstated the amount of change in the position of the 

 polar axis which was likely to result from the supposed belts of 

 elevation and depression. When, however, he was told that the 

 displacement would not exceed 10 miles, notwithstanding his 

 implicit faith in mathematics, there arose an inward feeling of 

 disbelief as to the conditions of the problem having been accurately 

 stated in order to obtain such a result. It seemed to him that the 

 author had treated the globe as an absolutely solid spheroid instead 

 of a terraqueous globe, with the proportions of land and sea upon 

 its surface as at present existing, which were important elements in 

 the case. 



The depth of the ocean in equatorial and polar regions ought 

 surely to be taken into account, as it was quite possible to conceive of 

 the irregularly shaped solid portion of the globe projecting in places 

 through a spheroidal coating of water, so as to form large tracts of 

 land, and yet on the average forming a sphere. Such a sphere, from 

 disturbances of its equilibrium, he believed would be much more 

 liable to changes in its axis than a spheroid; and the nearer a 

 spheroid approached a sphere the more sensible it would become to 

 such disturbances. 



He had never intended to suggest that the hypothetical belt was 

 to be suddenly elevated so as to produce the enormous tidal move- 

 ments of which the author spoke. On the contrary, he believed 

 that all such disturbances of equilibrium were gradual, and that 

 the axis of rotation and that of figure were never at any great 

 distance from each other. There was one portion of the paper 

 which he found difficult to comprehend. He could not conceive why 



* There are two papers in the Proc. Roy. Soc. on subjects allied to that of 

 the above paper — one by Mr. G-. Darwin, vol. xxv. p. 328, the other by Professor 

 Haughton, vol. xxvi. p. 51. The objects the writers have in view are by no 

 means the same as mine ; and they discuss questions which I have not touched ; 

 but their methods are similar to those which I have used, and, I think, it may 

 be added that their results tend to confirm those at which I had independently 

 arrived. 



