asus is also the first in
Andromeda.

[gamma] of Andromeda is a magnificent double orb, to which we shall
return in the next chapter, _i.e._, the telescope resolves it into two
marvelous suns, one of which is topaz-yellow, and the other
emerald-green. Three stars, indeed, are visible with more powerful
instruments.

[Illustration: FIG. 7.--Perseus, the Pleiades, Capella.]

Above [beta] and near a small star, is visible a faint, whitish,
luminous trail: this is the oblong nebula of Andromeda, the first
mentioned in the history of astronomy, and one of the most beautiful in
the Heavens, perceptible to the unaided eye on very clear nights.

The stars [alpha], [beta] and [gamma] of Perseus form a concave bow
which will serve in a new orientation. If it is prolonged in the
direction of [delta], we find a very brilliant star of the first
magnitude. This is Capella, the Goat, in the constellation of the
Charioteer (Fig. 7).

If coming back to [delta] in Perseus, a line is drawn toward the South,
we reach the Pleiades, a gorgeous cluster of stars, scintillating like
the finest dust of diamonds, on the shoulder of the Bull, to which we
shall come shortly, in studying the Constellations of the Zodiac.

Not far off is a very curious star, [beta] of Perseus, or Algol, which
forms a little triangle with two others smaller than itself. This star
is peculiar in that, instead of shining with a fixed light, it varies in
intensity, and is sometimes pale, sometimes brilliant. It belongs to the
category of variable stars which we shall study later on. All the
observations made on it for more than two hundred years go to prove that
a dark star revolves round this sun, almost in the plane of our line of
sight, producing as it passes in front of it a partial eclipse that
reduces it from the second to the fourth magnitude, every other two
days, twenty hours, and forty-nine minutes.

And now, let us return to the Great Bear, which aided us so beneficently
to start for these distant shores, and whence we shall set out afresh in
search of other constellations.

If we produce the curved line of the tail, or handle, we encounter a
magnificent golden-yellow star, a splendid sun of dazzling brilliancy:
let us make our bow to Arcturus, [alpha] of the Herdsman, which is at
the extremity of this pentagonal constellation. The principal stars of
this asterism are of the third magnitude, with the exception of [alpha],
which is of the first. Along