.
This hue, although not extremely uncommon among double stars elsewhere,
recurs again and again, with singular persistence, in this little
constellation. For instance, in the very next star that we look at, 12,
we find a double whose smaller component is _lilac_. The magnitudes in
12 are five and eight, distance 66", p. 168 deg.. So also the wide double
17, magnitudes five and a half and six, distance 145", exhibits a tinge
of _lilac_ in the smaller component; the triple 35, magnitudes five,
eight, and nine, distances 1", p. 77 deg., and 28.7", p. 124 deg., has four
colors yellow, _lilac_, and blue, and the double 24, magnitudes five and
six, distance 20", p. 270 deg., combines an orange with a _lilac_ star, a
very striking and beautiful contrast. We should make a mistake if we
regarded this wonderful distribution of color among the double stars as
accidental. It is manifestly expressive of their physical condition,
although we can not yet decipher its exact meaning.

The binary 42 Comae Berenicis is too close for ordinary telescopes, but
it is highly interesting as an intermediate between those pairs which
the telescope is able to separate and those--like beta Aurigae--which no
magnifying power can divide, but which reveal the fact that they are
double by the periodical splitting of their spectral lines. The orbit in
42 Comae Berenicis is a very small one, so that even when the components
are at their greatest distance apart they can not be separated by a
five-or six-inch glass. Burnham, using the Lick telescope, in 1890 made
the distance 0.7"; Hall, using the Washington telescope, in 1891 made it
a trifle more than 0.5". He had measured it in 1886 as only 0.27". The
period of revolution is believed to be about twenty-five years.

In Coma Berenices there is an outlying field of the marvelous nebulous
region of Virgo, which we may explore on some future evening. But the
nebulae in Coma are very faint, and, for an amateur, hardly worth the
trouble required to pick them up. The two clusters included in the map,
2752 and 3453, are bright enough to repay inspection with our largest
aperture.

[Illustration: MAP NO. 7.]

Although Hydra is the largest constellation in the heavens, extending
about seven hours, or 105 deg., in right ascension, it contains
comparatively few objects of interest, and most of these are in the head
or western end of the constellation, which we examined during our first
night at the telescope. I