lation of Lyra.]

The tail of the Great Bear, when prolonged with a continuation of the
curve which it possesses, leads to a brilliant star of the first
magnitude known as Arcturus, the principal star in the constellation of
Booetes (Fig. 88). A few other stars, marked b, g, d,
and e in the same constellation, are also shown in the figure.
Among the stars visible in these latitudes Arcturus is to be placed next
to Sirius in point of brightness. Two stars in the southern hemisphere,
invisible in these latitudes, termed a Centauri and Canopus, are
nearly as bright as Vega and Capella, but not quite as bright as
Arcturus.

In the immediate neighbourhood of Booetes is a striking semicircular
group known as the Crown or Corona Borealis. It will be readily found
from its position as indicated in the figure, or it may be identified by
following the curved line indicated by b, d, e, and z in the Great Bear.

[Illustration: Fig. 91.--Vega, the Swan, and the Eagle.]

The constellation of Virgo is principally characterised by the first
magnitude star called Spica, or a Virginis. This may be found from
the Great Bear; for if the line joining the two stars a and
g in that constellation be prolonged with a slight curve, it will
conduct the eye to Spica. We may here notice another of those large
configurations which are of great assistance in the study of the stars.
There is a fine equilateral triangle, whereof Arcturus and Spica form
two of the corners, while the third is indicated by Denebola, the bright
star near the tail of the Lion (Fig. 89).

In the summer evenings when the Crown is overhead, a line from the Pole
Star through its fainter edge, continued nearly to the southern horizon,
encounters the brilliant red star Cor Scorpionis, or the Scorpion's
Heart (Antares), which was the first star mentioned as having been seen
with the telescope in the daytime.

The first magnitude star, Vega, in the constellation of the Lyre, can
be readily found at the corner of a bold triangle, of which the Pole
Star and Arcturus form the base (Fig. 90). The brilliant whiteness of
Vega will arrest the attention, while the small group of neighbouring
stars which form the Lyre produces one of the best defined
constellations.

Near Vega is another important constellation, known as the Swan or
Cygnus. The brightest star will be identified as the vertex of a
right-angled triangle, of which the line from Vega to the Pole Star is
the base, as sh