into two
parts, determined by new moon and full moon (Cambodia, Siam; cf. the
Mexican period of thirteen days). The division into three periods of
ten days each (Egypt, Greece, Annam, Japan) ignores lunar phases and
seeks a convenient and symmetrical arrangement. With this decimal system
is perhaps connected the division of the month into six periods of five
days each (Yoruba, Java, Sumatra, and perhaps Babylonia). The Romans had
a somewhat irregular official division of the first half of the month
into three parts (Kalends, Nones, Ides) corresponding in a general way
to lunar phases, and also commercial periods of eight days (_nundinae_),
perhaps of similar origin. A seven-day division is found in Ashantiland
(and perhaps in Peru), and in Java there is reported a division of a
year into thirty periods of seven days each.

+607+. It appears, then, that in several communities there has been a
division of the month in the interests of convenience, without regard to
lunar phases; that in several cases a seven-day week has been fallen
upon; and that of the phases of the moon new moon and full moon have
been most frequently looked to as chronological marks. The new moon,
apart from its function of indicating the beginning of the lunar month,
has also by many tribes been hailed with joy as a friend restored to
life after seeming extinction.[993] The full moon, while it has not
entered so intimately into the emotional life of man, has played an
important part by marking the division of the month into two equal
parts.

+608+. _The Hebrew sabbath._ Taboo days are days of abstinence from
work, set apart as seasons of rest.[994] Such was the original form of
the Hebrew sabbath--it is described in the earlier Old Testament notices
simply as a day on which ordinary work was unlawful.[995] The history of
its precise origin and development is, however, by no means clear.
Theories that derive it from the cult of some particular deity or
regard it as primarily a day for placating a supernatural Power[996] may
be set aside. It may be assumed that it is an early institution somehow
connected with the moon, and a definite indication of origin appears to
be furnished by the fact that in a Babylonian inscription the term
_shabattu_[997] is used for the full moon. The identification of Hebrew
sabbath with full moon is favored by the collocation of new moon and
sabbath in early Old Testament documents[998] as days on which trading
was unlawf