172 
It was suggested that there are three causes which might 
change the position of the axis, viz., distortion of the earth 
by continental and local upheaval alteriog the centre of 
gravity, and thus changing 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. Millard Keade, in a paper on Geolo- 
gical Time, read as a presidential address to the Liverpool 
Geol. Soc., 1876-77, about one ton of solid matter is removed 
in solution by the drainage in each square mile, so that it 
was shown about 5000 million tons are removed from the 
land surface each year ; so that in ten years a weight equal 
to that of Vesuvius is removed from the land to the oceanic 
area by this means ; and as there is more land in the north- 
ern hemisphere, this gives a gain for the southern hemi- 
sphere of 3230 million tons over the northern. If 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 Vesuvius in twelve years, 
the place of greatest gain being about 45° S. and the great- 
est loss 45° N. in antipodal positions. 
A statement of Sir G. B. Airy’s in the “ Athenseuin,” 
1860, was taken to see what effect special alteration would 
have. 
Bemoving 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- 
