ession of the fact, that the
actual distances of a few out of the great host can be calculated.

To mention some of these. The nearest star to the earth, so far as we
yet know, is Alpha Centauri, which is distant from us about 25 billions
of miles. The light from this star, travelling at the stupendous rate of
about 186,000 miles per second, takes about 4-1/4 years to reach our
earth, or, to speak astronomically, Alpha Centauri is about 4-1/4 "light
years" distant from us. Sirius--the brightest star in the whole sky--is
at twice this distance, _i.e._ about 8-1/2 light years. Vega is about 30
light years distant from us, Capella about 32, and Arcturus about 100.

The displacements, consequent on the earth's movement, have, however,
plainly nothing to say to any real movements on the part of the stars
themselves. The old idea was that the stars were absolutely fixed; hence
arose the term "fixed stars"--a term which, though inaccurate, has not
yet been entirely banished from the astronomical vocabulary. But careful
observations extending over a number of years have shown slight changes
of position among these bodies; and such alterations cannot be ascribed
to the revolution of the earth in its orbit, for they appear to take
place in every direction. These evidences of movement are known as
"proper motions," that is to say, actual motions in space proper to the
stars themselves. Stars which are comparatively near to us show, as a
rule, greater proper motions than those which are farther off. It must
not, however, be concluded that these proper motions are of any very
noticeable amounts. They are, as a matter of fact, merely upon the same
apparently minute scale as other changes in the heavens; and would
largely remain unnoticed were it not for the great precision of modern
astronomical instruments.

One of the swiftest moving of the stars is a star of the sixth magnitude
in the constellation of the Great Bear; which is known as "1830
Groombridge," because this was the number assigned to it in a catalogue
of stars made by an astronomer of that name. It is popularly known as
the "Runaway Star," a name given to it by Professor Newcomb. Its speed
is estimated to be at least 138 miles per second. It may be actually
moving at a much greater rate, for it is possible that we see its path
somewhat foreshortened.

A still greater proper motion--the greatest, in fact, known--is that of
an eighth magnitude star in the southern hemis