still more the plants, which form his food, appear, at certain others
they disappear. It is these times that become the central points, the
focuses of his interest, and the dates of his religious festivals. These
dates will vary, of course, in different countries and in different
climates. It is, therefore, idle to attempt a study of the ritual of a
people without knowing the facts of their climate and surroundings. In
Egypt the food supply will depend on the rise and fall of the Nile, and
on this rise and fall will depend the ritual and calendar of Osiris. And
yet treatises on Egyptian religion are still to be found which begin by
recounting the rites and mythology of Osiris, as though these were
primary, and then end with a corollary to the effect that these rites
and this calendar were "associated" with the worship of Osiris, or, even
worse still, "instituted by" the religion of Osiris. The Nile regulates
the food supply of Egypt, the monsoon that of certain South Pacific
islands; the calendar of Egypt depends on the Nile, of the South
Pacific islands on the monsoon.

* * * * *

In his recent _Introduction to Mathematics_[7] Dr. Whitehead has pointed
out how the "whole life of Nature is dominated by the existence of
periodic events." The rotation of the earth produces successive days;
the path of the earth round the sun leads to the yearly recurrence of
the seasons; the phases of the moon are recurrent, and though artificial
light has made these phases pass almost unnoticed to-day, in climates
where the skies are clear, human life was largely influenced by
moonlight. Even our own bodily life, with its recurrent heart-beats and
breathings, is essentially periodic.[8] The presupposition of
periodicity is indeed fundamental to our very conception of life, and
but for periodicity the very means of measuring time as a quantity would