Adams, Walter M.: The house of the hidden places: a clue to the creed of early Egypt from Egyptian sources (London, 1895)

IV.] The Hour and the Day. 115

between the lunar period and the risings of
the stars, which was also utilized by the
Egyptian astronomers. For whereas in regard
to the apparent position of the sun, relatively
to the rest of the heavens, the motion of the
earth in her orbit has a perceptible effect;
in regard to the stars, the distances are so
enormous that the orbit of the earth shrinks
into insignificance. The time therefore which
elapses between any two successive risings of
the same star at any given place will, on the
average, be a little less than that between any
two successive risings of the sun at that place ;
since in the first case the time depends only
upon the complete rotation of the place round
the centre of the earth, whereas in the latter,
the motion of the earth's centre durintr the
interval must be taken into account. This
difference is, on the average, about four
minutes in every twenty-four hours, and will,
therefore, in fifteen days, amount to an hour.
Accordingly,as we learn from a most interesting