t; very
large; very bright, and very much compressed in the middle.' The
interior mass consists of closely aggregated pale rose-coloured stars,
surrounded by others of a pure white which embrace the remainder of the
cluster. There is a fine globular cluster in Sagittarius between the
Archer's head and the bow. It was observed by Hevelius in 1665. The
central portion is very much compressed, and consists of excessively
minute stars enclosed by others of larger size. In Aquarius there is a
magnificent ball of stars of a beautiful spherical form, which Sir J.
Herschel compared to a heap of fine sand. Numerous other clusters are
profusely distributed over the heavens, occupying regions in the
profound depths of space which can only be reached by the aid of most
powerful instruments.

The finest and most remarkable object of this class visible in the
northern heavens is the Great Cluster which lies between Eta and Zeta
Herculis. It was discovered by Halley in 1714, who writes: 'This is but
a little patch, but it shows itself to the naked eye when the sky is
serene and the moon absent.' When observed with a powerful telescope its
magnificence at once becomes apparent to the beholder. 'Perhaps,' says
Dr. Nichol, 'no one ever saw it for the first time through a telescope
without uttering a shout of wonder.' At its circumference the stars are
rather scattered, but towards the centre they appear so closely
aggregated that their combined effulgence forms a perfect blaze of
light. Sir William Herschel estimated that there are 14,000 stars in the
cluster, each a magnificent world but unaccompanied by any planetary
attendants.

[Illustration: CLUSTER IN HERCULES]

As a result of more recent investigations this number has been
considerably reduced, and it is now generally believed that about 4,000
stars enter into the formation of the cluster. As its distance from the
Earth is unknown, it follows that there must be some uncertainty
attached to any conclusions that may be arrived at with regard to this
superb object. Miss Agnes Clerke estimates the number of the constituent
stars at 4,000, and in support of her conclusion this talented lady
writes as follows: 'The apparent diameter of this object, including most
of the "scattered stars in streaky masses and lines" which form a sort
of "glory" round it, is 8'; that of its truly spherical portion may be
put at 5'. Now, a globe subtending an angle of 5' must have (because the
sine of