220 
Notice of Nemoirs — A. W. Wafers. 
It was suggested that there are three causes whicli might change 
the position of the axis, viz. distortion of the earth by Continental 
and local upheaval altering the centre of gravity, and thus ckanging 
the position of the axis ; the removal of water by elevation of land 
displacing the ocean : and the removal of matter in solution ; and 
these two last, though not considered to be the most important 
in amount, were considered more in detail. 
According to Mr. T. Mellard Eeade, 1 about one ton of solid matter 
is removed in solution by the drainage of each square mile, so that 
about 5000 million tons are removed from the land surface eaeh 
year; thus in ten years a weight equal to that of Vesuvius 
is removed from the land to the oceanic area by tbis means ; 
and as there is more land in the northem hemispliere, tbis 
gives a gain for the Southern hemisphere of 3230 million tons 
over the northern. lf the earth is divided into a land and water 
hemisphere, with England as a centre, the gain of the weight of 
the water hemisphere is about 4300 million tons, or one Yesuvius 
in twelve years, the place of greatest gain being about 45° S. and the 
greatest loss 45° N. in antipodal positions. 
A statement by Sir G. B. Airy in the Athenceum, 1860, was 
considered in Order to see what effect special alteration would have. 
Kemoving a weight equal to that of Asia 1000 feet high from the 
centre of the land hemisphere, and adding a similar weight at the 
antipodes in a sinking Pacific Ocean, leaving the remaining portion 
in each hemisphere balanced by the natural configuration, would 
give an alteration of from 18-27 miles. This alone would require 
13 million years at the present rate of denudation, but there are 
many causes, some of which were mentioned, which would very 
much reduce the time required for this amount of “ soluble denuda- 
tion,” so that it might be reduced to one or two million years, and 
the vast thickness of calcareous rocks, which are only the record of 
others from which they were partly formed, shows how many times 
such areas must have been transported from land to sea. 
The sinking of an area equal to the continent of Asia to the mean 
depth of the ocean would bring a weight of water sufficient, if the 
antipodes were a suboceanic rising area, to displace the position 
of the axis 40 — 60 miles by the same method of calculation. It is 
thus seen that these may be disturbing or starting forces, but do 
not give a large amount of change directly, and that the one to three 
degrees which Mr. George H. Darwin, M.A., 1 allows is all that we 
should expect in recent geological times, unless there is some cumu- 
lative effect. 
Mr. Waters maintained that if the change was caused by addition 
of weight, then the earth in re-adjustment would cause phenomena 
equivalent to an elevation in those semi-hemispheres from which the 
maximum bulge has been removed, displacing, if it should be an 
oceanic area, an amount of water to be placed in another region ; the 
1 In a paper on Geological Time, read as a presidential address to the Liverpool 
Geol. Soc. 1876-77. 
2 Proc. Boy. Soc., No. 17o, 1876. 
