dian, and then observe them more comfortably.
Besides, most objects are higher, and therefore better seen, when due
south.

Northern objects, and especially those within the circle of perpetual
apparition, often culminate (that is, cross the meridian, or north and
south line) at too great a height for comfortable vision. In this case
we should observe them towards the east or west, and remember that in
the first case they are rising, and in the latter they are setting, and
that in both cases they have also a motion from left to right.

If we allow an object to pass right across the field of view (the
telescope being fixed), the apparent direction of its motion is the
exact reverse of the true direction of the star's motion. This will
serve as a guide in shifting the alt-azimuth after a star has passed out
of the field of view.

The following technical terms must be explained. That part of the field
of view towards which the star appears to move is called the _preceding_
part of the field, the opposite being termed the _following_ part. The
motion for all stars, except those lying in an oval space extending from
the zenith to the pole of the heavens, is more or less from right to
left (in the inverted field). Now, if we suppose a star to move along a
diameter of the field so as to divide the field into two semicircles,
then in all cases in which this motion takes places from right to left,
that semicircle which contains the lowest point (apparently) of the
field is the _northern_ half, the other is the _southern_ half. Over the
oval space just mentioned the reverse holds.

Thus the field is divided into four quadrants, and these are termed
_north following_ (_n.f._) and _south following_ (_s.f._); _north
preceding_ (_n.p._), and _south preceding_ (_s.p._). The student can
have no difficulty in interpreting these terms, since he knows which is
the following and which the preceding _semicircle_, which the northern
and which the southern. In the figures of plates 3 and 5, the letters
_n.f._, _n.p._, &c., are affixed to the proper quadrants. It is to be
remembered that the quadrants thus indicated are measured either way
from the point and feather of the diametral arrows.

Next, of the apparent annual motion of the stars. This takes place in
exactly the same manner as the daily motion. If we view the sky at eight
o'clock on any day, and again at the same hour one month later, we shall
find that at the latter observation