r is a binary system with a long period of
revolution, estimated at about two hundred years. We discover another
group of remarkable doubles in 67, 70, and 73. In the first-named star
the magnitudes are four and eight, distance 55", p. 144 deg., colors
finely contrasted, pale yellow and red.

Much more interesting, however, is 70, a binary whose components have
completed a revolution since their discovery by Sir William Herschel,
the period being ninety-five years. The magnitudes are four and six, or,
according to Hall, five and six, distance in 1894 2.3"; in 1900, 1.45",
according to Maw. Hall says the apparent distance when the stars are
closest is about 1.7", and when they are widest 6.7". This star is one
of those whose parallax has been calculated with a reasonable degree of
accuracy. Its distance from us is about 1,260,000 times the distance of
the sun, the average distance apart of the two stars is about
2,800,000,000 miles (equal to the distance of Neptune from the sun), and
their combined mass is three times that of the sun. Hall has seen in the
system of 70 Ophiuchi three stars of the thirteenth magnitude or less,
at distances of about 60", 90", and 165" respectively.

The star 73 is also a close double, and beyond our reach. Its magnitudes
are six and seven, distance 0.7", p. 245 deg.. It is, no doubt, a binary.

Three star clusters in Ophiuchus remain to be examined. The first of
these, No. 4256, is partially resolved into stars by the five-inch. No.
4315 is globular, and has a striking environment of bystanding stars. It
is about one quarter as broad as the full moon, and our largest aperture
reveals the faint coruscation of its crowded components. No. 4410 is a
coarser and more scattered star swarm--a fine sight!

Farther toward the east we encounter a part of Serpens again, which
contains just one object worth glancing at, the double theta, whose
stars are of magnitudes four and four and a half, distance 21", p. 104 deg..
Color, both yellow, the smaller star having the deeper hue.

[Illustration: MAP NO. 15.]

Let us next, with the guidance of map No. 15, enter the rich star fields
of Hercules, and of the head and first coils of Draco. According to
Argelander, Hercules contains more stars visible to the naked eye than
any other constellation, and he makes the number of them one hundred and
fifty-five, nearly two thirds of which are only of the sixth magnitude.
But Heis, who saw more naked-eye stars t