The observations now to be commenced are supposed to take place during
the second quarter of the year,--at ten o'clock on the 20th of April, or
at nine on the 5th of May, or at eight on the 21st of May, or at seven
on the 5th of June, or at hours intermediate to these on intermediate
days.

We again look first for the Great Bear, now near the zenith, and thence
find the Pole-star. Turning towards the north, we see Cassiopeia between
the Pole-star and the horizon. Towards the north-west is the brilliant
Capella, and towards the north-east the equally brilliant Vega, beneath
which, and somewhat northerly, is the cross in Cygnus. The Milky Way
passes from the eastern horizon towards the north (low down), and so
round to the western horizon.

In selecting a region for special observation, we shall adopt a
different plan from that used in the preceding "half-hour." The region
on the equator and towards the south is indeed particularly interesting,
since it includes the nebular region in Virgo. Within this space nebulæ
are clustered more closely than over any corresponding space in the
heavens, save only the greater Magellanic cloud. But to the observer
with telescopes of moderate power these nebulæ present few features of
special interest; and there are regions of the sky now well situated for
observation, which, at most other epochs are either low down towards
the horizon or inconveniently near to the zenith. We shall therefore
select one of these, the region included in the second map of Plate 2,
and the neighbouring part of the celestial sphere.

At any of the hours above named, the constellation Hercules lies towards
the east. A quadrant taken from the zenith to the eastern horizon passes