54 General Notes. [January, 
that there has been and is a continuous circulation of the mate- 
rial of the solid land from the continents to the ocean, and from 
the ocean back to the continents again, a circulation, in some de- 
gree, like what is taking place in the ocean between the equator 
and the poles, that is, a bodily transfer of superficial materials one 
way and a siow general under-creep of materials back. 
But how is sucha system possible and how can it be maintained ? 
If we assume, as appears to be required by both physical princi- 
ples and geological facts, that the earth’s surface is only slightly 
out of equilibrium and is constantly tending toward that state, 
then any transfer of material from the continents to the ocean 
would cause a subsidence of the ocean beds which, in turn, must 
necessitate a setting of the deeper earth materials from beneath the 
ocean beds toward the continents causing them to rise. This cir- 
culation appears to be entirely possible and even probable, if not 
almost certain, and this too, while granting that the earth is essen- 
tially solid throughout and as rigid as glass. By this is meant, of 
course, as rigid as glass would be under the internal earth pres- 
sure 
from the views expressed by leading physicists in regard to the 
rigidity of the earth for, as I see it, there may be all the rigidity 
which physicists have claimed and yet all the mobility geological 
facts can demand. When cold metals are subjected to artificial 
pressure, causing their molecules to flow into new positions so 
that the form of the mass is greatly changed, it is not to be sup- 
posed that these metals while under such pressure are to be re- 
garded as true liquids, in any sense obedient to all the laws of 
fluids, nor could any mere pressure, however great, convert them 
into true liquids. I think it will not be maintained, even by those 
who believe “pressure itself would reduce the interior of the 
earth to a fluid condition,” that this fluid is such to the extent of 
permitting bodies moving freely through it as fish move through 
the sea; nor would they maintain that this interior fluid would 
remain such with the pressure removed. It could hardly be 
maintained either, that such a fluid would possess the degree of 
elasticity characteristle of true fluids, but unless these are insisted 
upon by geologists, physicists have all the rigidity they have 
claimed. 
Even if it is admitted that such a circulation is possible when con- 
ditions are once favorable, unless there is some disturbing agent 
continually working to destroy the equilibrium which the circu- 
lation tends to establish, eventually the earth’s surface must have 
existing differences of level greatly reduced. There appears no 
escape from the conclusion that the density of the earth increases 
as its center is approached. This being the case, a continual denu- 
dation from certain regions and constant sedimentation in others 
must, in due time, whatever may have been the original distribu- 
i 
It appears to me, geologists have no occasion for dissenting 
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