come arctic, and for its antithesis, antarctic. From
the Latin word _trio_ (ox of labor) has come septentrion, the seven
oxen. Etymology is not always logical. Is not the word "venerate"
derived from Venus?

In order to distinguish one star from another, the convention of
denoting them by the letters of the Greek Alphabet has been adopted, for
it would be impossible to give a name to each, so considerable is their
number.[3]

[alpha] and [beta] denote the front wheels of the Chariot generally
known as the "pointers;" [gamma] and [delta] the hind wheels; [epsilon],
[zeta], [eta] the three horses. All these stars are of the second order
of magnitude (the specific meaning of this expression will be explained
in the next chapter), except the last ([delta]) of the quadrilateral,
which is of the third order.

[Illustration: FIG. 3.--The Great Bear (or Dipper), and the Pole-Star.]

Figure 3 gives the outline of this primitive constellation. In revolving
in twenty-four hours round the Pole, which is situated at the
prolongation of a line drawn from [beta] to [alpha], it occupies every
conceivable position,--as if this page were turned in all directions.
But the relative arrangement of the seven stars remains unaltered. In
contemplating these seven stars it must never be forgotten that each is
a dazzling sun, a center of force and life. One of them is especially
remarkable: [zeta], known as Mizar to the Arabs. Those who have good
sight will distinguish near it a minute star, Alcor, or the Cavalier,
also called Saidak by the Arabs--that is, the Test, because it can be
used as a test of vision. But further, if you have a small telescope at
your disposal, direct it upon the fine star Mizar: you will be
astonished at discovering two of the finest diamonds you could wish to
see, with which no brilliant is comparable. There are several double
stars; these we shall become acquainted with later on.

Meantime, we must not forget our celestial geography. The Great Bear
will help us to find all the adjacent constellations.

[Illustration: FIG. 4.--To find the Pole-Star.]

If a straight line is drawn (Fig. 4) from [beta] through [alpha], which
forms the extremity of the square, and is prolonged by a quantity equal
to the distance of [alpha] from the tip of the handle, we come on a star
of second magnitude, which marks the extremity of a figure perfectly
comparable with the Great Bear, but smaller, less brilliant, and
pointing in th