reen component
intermediate between the fifth and sixth magnitudes.

We may now turn to a star not figured in the map, but readily found. It
will be noticed that the stars [epsilon], [alpha], [beta], and [gamma]
form, with two small stars towards the left, a somewhat regular
hexagonal figure--a hexagon, in fact, having three equal long sides and
three nearly equal short sides alternating with the others. The star
[eta] Lyrae forms the angle next to [epsilon]. It is a wide and unequal
double, as figured in Plate 3. The larger component is azure blue; the
smaller is violet, and, being only of the ninth magnitude, is somewhat
difficult to catch with apertures under 3 inches.

The star [delta]^{2} Lyrae is orange, [delta]^{1} blue. In the same field
with these are seen many other stars.

The stars [gamma]^{1} and [gamma]^{2} may also be seen in a single
field, the distance between them being about half the moon's mean
diameter. The former is quadruple, the components being yellow, bluish,
pale blue, and blue.

Turn next to the stars [beta] and [gamma] Lyrae, the former a multiple,
the latter an unequal double star. It is not, however, in these respects
that these stars are chiefly interesting, but for their variability. The
variability of [gamma] has not indeed been fully established, though it
is certain that, having once been less bright, [gamma] is now
considerably brighter than [beta]. The change, however, may be due to
the variation of [beta] alone. This star is one of the most remarkable
variables known. Its period is 12d. 21h. 53m. 10s. In this time it
passes from a maximum brilliancy--that of a star of the 3.4
magnitude--to a minimum lustre equal to that of a star of the 4.3
magnitude, thence to the same maximum brilliancy as before, thence to
another minimum of lustre--that of a star of the 4.5 magnitude--and so
to its maximum lustre again, when the cycle of changes recommences.
These remarkable changes seem to point to the existence of two unequal
dark satellites, whose dimensions bear a much greater proportion to
those of the bright components of [beta] Lyrae than the dimensions of the
members of the Solar System bear to those of the sun. In this case, at
any rate, the conjecture hazarded about Algol, that the star revolves
around a dark central orb, would be insufficient to account for the
observed variation.

Nearly midway between [beta] and [gamma] lies the wonderful ring-nebula
57 M, of which an imperfe