otal
eclipses as well as comets still give rise to feelings of anxiety and
alarm amongst ill-educated villagers even in so-called civilized
countries. Some amusing illustrations of this will be presented in due
course. For the moment let me content myself by stating the immediate
aim of this little book, and the circumstances which have led to its
being written. What those circumstances are will be understood generally
from what has been said already. Its aim is the unambitious one of
presenting in readable yet sound scientific language a popular account
of eclipses of the Sun and Moon, and (very briefly) of certain kindred
astronomical phenomena which depend upon causes in some degree similar
to those which operate in connection with eclipses. These kindred
phenomena are technically known as "Transits" and "Occultations."
Putting these two matters entirely aside for the present, we will
confine our attention in the first instance to eclipses; and as eclipses
of the Sun do not stand quite on the same footing as eclipses of the
Moon, we will, after stating the general circumstances of the case, put
the eclipses of the Moon aside for a while.

CHAPTER II.

GENERAL IDEAS.

The primary meaning of the word "Eclipse" ([Greek: ekleipsis]) is a
forsaking, quitting, or disappearance. Hence the covering over of
something by something else, or the immersion of something in something;
and these apparently crude definitions will be found on investigation to
represent precisely the facts of the case.

Inasmuch as the Earth and the Moon are for our present purpose
practically "solid bodies," each must cast a shadow into space as the
result of being illuminated by the Sun, regarded as a source of light.
What we shall eventually have to consider is: What results arise from
the existence of these shadows according to the circumstances under
which they are viewed? But before reaching this point, some other
preliminary considerations must be dealt with.

The various bodies which together make up the Solar system, that is to
say, in particular, those bodies called the "planets"--some of them
"primary," others "secondary" (_alias_ "Satellites" or "Moons")--are
constantly in motion. Consequently, if we imagine a line to be drawn
between any two at any given time, such a line will point in a different
direction at another time, and so it may occasionally happen that three