1875.] Variation in the Obliquity of the Ecliptic. 285 
size of the two continents, and immediately—like many 
modern asserters—talks nonsense. 
It is a law that a decrease in the obliquity of the ecliptic 
is the same thing as a decrease in the angular distance of 
the pole of the heavens from the pole of the ecliptic, and is 
the same thing as a decrease in the supposed radius of the 
circle described by the pole. Hence—in spite of assertions, 
of authority, and the many writers who have stated it to be 
so—it follows that the pole of the heavens does not, and has 
not at any time within historical periods, traced any part of 
a circle round the pole of the ecliptic as a centre. 
We now come to the most modern explanation of the 
facts known in conne¢tion with the change in dire¢tion of 
the earth’s axis, and the decrease in the obliquity. It has 
recently been stated that the plane (and hence the pole) of 
the ecliptic is slowly changing its position in the heavens, 
and thus bringing the pole of the heavens nearer to the pole 
of the ecliptic; that the pole of the heavens always moves 
at right angles to the are by which it would be joined to the 
pole of the ecliptic ; and that the two facts, viz., the move- 
ment of the pole of the heavens and the decrease in the 
obliquity, are thus accounted for. 
This is a question either of fact or theory. If it be a 
fact, it follows that the angular distance of all stars from 
the pole of the ecliptic—that is, their co-latitudes—will be 
found to have decreased in one part of the heavens, viz., in 
that part towards which the pole of the ecliptic is supposed 
to be moving, and the co-latitude of stars in the opposite 
part of the heavens will be found to have increased. In 
order that there should be a decrease in the angular distance 
of the pole of the ecliptic from the pole of the heavens, it 
follows that the movement of the pole of the ecliptic should 
be approximately towards that part of the heavens in which 
Sirius is situated, and away from that part in which a Lyre 
is located. ‘To prove this movement, all stars in one direc- 
tion must have decreased their co-latitudes; all stars in the 
other direction have increased their co-latitudes. After up- 
wards of seven years’ investigation, and after searching 
every catalogue of stars from that of Ptolemy to the latest, 
we fail to find any evidence of the assertion that such a 
movement of the pole of the ecliptic has occurred ; for there 
is not any defined change in the latitude of stars to prove 
that the pole of the ecliptic has moved towards that part of 
the heavens near the meridian of 6 hours’ right ascension. 
We have, however, to deal with two well-defined facts, 
viz., a change in direction of the earth’s axis of about 
