p. 262 deg., colors, according to Webb, "light apple-green and
cherry-red." But other observers have noted different hues, one calling
them both golden yellow. I think Webb's description is more nearly
correct. Sigma 2215 is a very close double, requiring larger telescopes
than those we are working with. Its magnitudes are six and a half and
eight, distance 0.7", p. 300 deg.. It is probably a binary. Sigma 2289 is
also close, but our five-inch will separate it: magnitudes six and
seven, distance 1.2", p. 230 deg..

Turning to , we have to deal with a triple, one of whose stars is at
present beyond the reach of our instruments. The magnitudes of the two
that we see are four and ten, distance 31", p. 243 deg.. The tenth-magnitude
star is a binary of short period (probably less than fifty years), the
distance of whose components was 2" in 1859, 1" in 1880, 0.34" in 1889,
and 0.54" in 1891, when the position angle was 25 deg., and rapidly
increasing. The distance is still much less than 1".

For a glance at a planetary nebula we may turn with the five-inch to No.
4234. It is very small and faint, only 8" in diameter, and equal in
brightness to an eighth-magnitude star. Only close gazing shows that it
is not sharply defined like a star, and that it possesses a bluish tint.
Its spectrum is gaseous.

The chief attraction of Hercules we have left for the last, the famous
star cluster between eta and zeta, No. 4230, more commonly known as M
13. On a still evening in the early summer, when the moon is absent and
the quiet that the earth enjoys seems an influence descending from the
brooding stars, the spectacle of this sun cluster in Hercules, viewed
with a telescope of not less than five-inches aperture, captivates the
mind of the most uncontemplative observer. With the Lick telescope I
have watched it resolve into separate stars to its very center--a scene
of marvelous beauty and impressiveness. But smaller instruments reveal
only the in-running star streams and the sprinkling of stellar points
over the main aggregation, which cause it to sparkle like a cloud of
diamond dust transfused with sunbeams. The appearance of flocking
together that those uncountable thousands of stars present calls up at
once a picture of our lone sun separated from its nearest stellar
neighbor by a distance probably a hundred times as great as the entire
diameter of the spherical space within which that multitude is
congregated. It is true that unle