AKE THERE ANY FIXED STARS? 
359 
surround it on every side, and the interest which attaches to its 
solution, before we proceed to consider the method which has 
been successfully applied to one star, and will doubtless in the 
fulness of time be applied to hundreds, with results whose 
importance it is impossible to over-estimate. 
The stars, it is well known, have to ordinary observers every 
appearance of fixity. If Hipparchus or Ptolemy could now 
look on the orbs they watched so lovingly in the far-off years, 
they would see nothing to induce them to imagine that the stars 
are in motion. Whether the aspect of the heavens is exactly 
the same now as when Aratus sang the glories of the constella- 
tions, we cannot indeed assert with any certainty of conviction. 
Many of the stars may shine with different lustre, some few 
have perhaps disappeared, and possibly some new stars have 
appeared upon the scene. But such changes as these are not 
in question at present ; I refer only to apparent changes in the 
stars’ places. 
Astronomers in our day know indeed that the stars are 
changing their place upon the heavens. But it is not because 
the change of place has been made perceptible to ordinary 
vision ; but because by means of the telescope it has become 
possible to magnify so largely the effects of change, that move- 
ments which would produce no perceptible effect in thousands 
of years if ordinary vision only were in question, are recognised 
as certainly as though the astronomer could see the star actually 
moving as he watched it. 
But such changes of position as can thus be recognised are 
not only minute, insomuch that it is only after half a century of 
observation that even modern astronomy can detect them, but 
they afford no certain indication of real motion on the part of 
the star. We may be in motion — nay, more, it has been proved 
that we are in motion, that the sun with his whole cortege 
of planets and cometary systems is sweeping swiftly through 
space, and the apparent motion of a star may in reality be 
wholly due to the sun’s motion. The very fact that by observ- 
ing the apparent stellar motions astronomers have been able to 
guess the direction in which the sun is travelling through space 
shows that a large part at any rate of the stellar motions must 
be due to the sun’s motion. And inasmuch as we are by no 
means certain of the direction in which the sun is moving, or of 
the velocity with which he rushes through space, we are not in 
any case able to determine how much or how little of a star’s 
apparent motion is due to the solar proper motion. Further- 
more, our uncertainty as to the distances of all save one or two 
stars renders us yet more doubtful how to interpret the stellar 
movements. 
Still we may take it as proved by the mere determination of 
