1875.] Variation in the Obliquity of the Ecliptic. 295 
ist. The course traced by the earth’s axis during the past 
2000 years corresponds to an arc of a circle, having for its 
centre the point 6° from the pole of the ecliptic, and so 
situated that at about the date a.p. 2298 the pole of the 
heavens, the pole of the ecliptic, and this centre will be in the 
arc of a great circle. The result of such a course would 
be to cause an obliquity of about 35° at a date about 
13,000 B.C. 
and. The evidence of Geology is positive as regards the 
existence of glaciers, in former times, in localities down to 
about 54° lat. ‘Thus astronomical facts and geological evi- 
dence agree as regards this course of the pole. 
3rd. The fact that the elevation of land in one hemisphere, 
or in one locality, will cause a transfer of water, and hence 
a removal of the locality of the earth’s centre of gravity, 
must produce a change in the movement of the earth’s axis, 
so that this movement cannot be uniform for all time. 
4th. The positive assertions of former theorists, that no 
change greater than about 1° 21’ could occur in the variation 
of the obliquity is based on two errors :—First, this conclu- 
sion was arrived at because it was supposed the plane of the 
eclipttc could vary only to this small amount, and, secondly, 
because the variation in the position of the earth’s centre of 
gravity was entirely overlooked. 
5th. The real problem relative to the variation in the ob- 
liquity has little or nothing to do with any change in the 
position of the plane of the ecliptic, but it has to do with 
the change in the direction of the earth’s axis, and therefore 
is dependent on the change in position of the earth’s centre 
of gravity produced by the transfer of water from one part 
to another. 
6th. The present somewhat dogmatic theory, that no 
change whatever greater than 1° 21’ has occurred in the ob- 
liquity, assumes that the earth is homogeneous, that the 
earth’s centre of gravity is situated in the plane of the 
Equator, and was formerly always where it now is. That the 
earth is homogeneous isa speculation only. That the centre 
of gravity is located in the plane of the Equator cannot be 
true if the earth is homogeneous. And it is an undeniable 
fact, due to the known distribution of land and sea in former 
times, that the earth’s centre of gravity was not in the past 
where it now is. 
It thus appears that this problem has yet to be investi- 
gated, for the present accepted theory is based on errors or 
omissions, and is opposed to fa¢ts. Its advocates have too 
often to ignore disagreeable facts, and to start on assumptions 
VOL. V. (N.S.) 2P 
