fact that these extremes of temperature are associated in some
way with the change of the sun's place in the heavens must, in
time, have impressed itself upon even a rudimentary intelligence.
It is hardly necessary to add that this is not meant to imply any
definite knowledge of the real meaning of, the seeming
oscillations of the sun. We shall see that, even at a relatively
late period, the vaguest notions were still in vogue as to the
cause of the sun's changes of position.

That the sun, moon, and stars move across the heavens must
obviously have been among the earliest scientific observations.
It must not be inferred, however, that this observation implied a
necessary conception of the complete revolution of these bodies
about the earth. It is unnecessary to speculate here as to how
the primitive intelligence conceived the transfer of the sun from
the western to the eastern horizon, to be effected each night,
for we shall have occasion to examine some historical
speculations regarding this phenomenon. We may assume, however,
that the idea of the transfer of the heavenly bodies beneath the
earth (whatever the conception as to the form of that body) must
early have presented itself.

It required a relatively high development of the observing
faculties, yet a development which man must have attained ages
before the historical period, to note that the moon has a
secondary motion, which leads it to shift its relative position
in the heavens, as regards the stars; that the stars themselves,
on the other hand, keep a fixed relation as regards one another,
with the notable exception of two or three of the most brilliant
members of the galaxy, the latter being the bodies which came to