The morning call. [volume] (San Francisco [Calif.]) 1878-1895, 1893-01-29
THE AZTEC CALENDAR.
A Year of Eighteen Months Each
With Twenty Days.


In the measurement OF time the Aztecs
adjusted their civil year by the solar year.
They divided it into eighteen months Of
twenty DAYS each. Both months and days
were expressed by peculiar bierogl yphics.
Five complementary days, as in Egypt,
were added to make up the full number of
Goo These belonged to no month. and were
regarded as peculiarly unlucky. month
was divided into four weeks OF five DAYS
each, on the last Of which was the public
fair or maIket-day. AS the year is COM
posed Of nearly six hours more than 365
DAYS. there still remained an excess, which.
like other nations who have framed a cal
eudar, they provided for by INTERPOLATION
not, Indeed. every fourth year as the Euro
peans, bnt al longer intervals, like same of
the Asiatirs. They waited till the expira-
ton OF hfty-two vague years, when they
interpOSed thirteen days, or rather twelve
and half, this being the number when
had fallen in arrear. Had they inserted
thirteen IL would have been too much, since
the annual excess over 800 Is about eleven
minutes less than six hours.
But as their calendar at the time OF the
conquest was found 10 correspond with the
European, making allowance for the subse-
quent GregOrian reform. they would seem
10 have adopted the shorter period Of twelve
days aud half. which brought them, with
IN an almost tnappreciab,e iractlOn, to TIL
exact length of the tropical year. as estab-
lished by the most accurate of ObSerya-
tons. Indeed. the intercalation OF twenty
five days in every 104 years shows a nicer
adjustment OF civil 20 solar time than is
presented by any European calendar: since
more than five centuries must elapse before
the loss of an entire day. Such was the
astonishing precision displayed by the
AZtecs, or perhaps by their more polished
TOtec predecessors, in these computations.
Their chronological system was reckoned
Christian era. 1t was the period OF the re-
form of their calendar. soon after their mi
grafton from AZatlan.
In addition to the solar calendar. as above
described. the Aztec priests had another
called lunar reckoning" though IN no.
wise accommodated to the revolutions of
the moon. 1t was formed also # two peri
Odca series. BY means Of this calendar
the priests kept their own records, regu-
lated the festivals and seasons of sacrifire
and made all their astrological calculations.
The astrological scheme of the AZtecs was
founded less on the planetary influences
than on those Of the arbitrary signs they
had adopted for the months and days. We
know Of no astronomical instruments used
by them except the dial. Tie calendar
sIone Gas it is called shows they had the
means of settling the hours Of the day with
precision, the periods of the s0'stices and
the equinoxes, and that of The transit of the
sun across the zenith Of Mexico.
There have been prOpounded from time
10 time theories that the calendar-stone of
the AZtecs Is In reality a representation of
the mariners compass ard is to be accepted
as proof that the AZtecs came from Asian
coasts or Pacific Islands. There does not
seem as yet TO be any valid reason for con-
StdoriuU thpsa thPOrsPg SprtOuSlV.