1878.] 
The British Association . 
535 
appear to be all in accord as to the extent of such changes. 
Mr. Twisden, for instance, arrives at the conclusion that the 
elevation of a belt twenty degrees in width, such as that 
which he (the president) suggested in his presidential ad- 
dress to the Geological Society in 1876, would displace the 
axis by about ten miles only, while Professor Haughton 
maintains that the elevation of two such continents as 
Europe and Asia would displace it by about sixty-nine miles, 
and Sir W. Thomson has not only admitted, but asserted as 
highly probable, that the poles may have been in ancient 
times “ very far from their present geographical position, 
and may have gradually shifted through ten, twenty, thirty, 
forty, or more degrees without at any time any perceptible 
sudden disturbance of either land or water.” 
The President was glad to think that this question, to which 
he had to some extent assisted to diredt attention, had been so 
fully discussed, but he could hardly regard its discussion as 
being now finally closed. It appeared to him doubtful whether 
eventually it would be found possible to concede to this 
globe that amount of solidity and rigidity which at present 
it is held to possess, and which to his mind at all events 
seemed to be in entire disaccordance with many geological 
phenomena. Yet this, as the Rev. O. Fisher has remarked, 
is presupposed in all the numerical calculations which have 
been made. He was also doubtful whether in the calcula- 
tions which have been made, sufficient regard has been shown 
to the fadf that a great part of the exterior of our spheroidal 
globe consists of fluid which, though of course connected 
with the more solid part of the globe by gravity, is readily 
capable of readjusting itself upon its surface, and may, to a 
great extent, be left out of the account in considering what 
changes might arise from the disturbance of the equilibrium 
of the irregular spherical or spheroidal body which it par- 
tially covers. It appeared to him also possible that some 
disturbances of equilibrium may take place in a mysterious 
manner by the redistribution of matter or otherwise in the 
interior of the globe. Captain F. j. Evans, arguing from 
the changes now going on in terrestrial magnetism, has 
suggested the possibility of some secular changes being due 
to internal, and not to external causes ; and if it be really 
true that there is a difference between the longest and 
shortest equatorial radii of the earth, amounting to six thou- 
sand three hundred and seventy-eight feet, such afaft would 
appear to point to a great want of homogeneity in the 
interior of our planet, and might suggest a possible cause 
for some disturbance of equilibrium. 
