On pages 51 to 58 of the Dresden Codex occurs a series of numbers,
running continuously through all the pages except the upper halves of
the first two. This series records a period of 11,960 days, divided by
means of columns into sixty-nine unequal subdivisions, of 177, 148, and
178 days, of which the first is the most frequent.
There are three distinct series. One series of numbers is in the upper
part of the record, and consists of totals increased step by step until
the final total reached records 11,958 days. Just below this series are
three series of day signs and numbers, the middle one of which is the
actual series. These dates are separated by the same number of days as
the upper number series, except in the 23d group, at which place one
extra day is added to the day series and not to the upper number series,
causing the former to be in advance of the latter one day throughout the
remainder of the record. At the end of the day series another extra day
is added by counting in the last day in the lower row of days, thus
completing the 11,960-day period.
Below this day series is another number series no term of which exceeds
178. In a general way it records the differences between the dates
appearing above each of its numbers. The agreement is however so
inaccurate that this lower number series could, at best, have been used
only as a general guide to the user of the manuscript, in that it calls
attention to the intervals of unusual length.
The series recorded is composed of three equal parts, each composed of
23 subdivisions and covering 3986 days.
The number series on these pages record an eclipse calendar, that is, a
series of dates by means of which the occurrence of eclipses was
foretold. This calendar is composed of three identical parts, with the
exception of one 148-day group which occurs six months earlier in the
last third than in the other two. Each third is composed of 23 unequal
subdivisions which represent the twenty-three eclipse seasons, expressed
in lunar months, in 3986 days. The upper number series records this
calendar, and its total of 11,958 days is only .39 days less than 69
eclipse seasons.
In order to make it more intelligible this eclipse calendar is
accompanied by a probably more generally known lunar calendar, which may
have been altered slightly to conform to the requirements of the eclipse
calendar it accompanies. This lunar calendar is contained in the day
series just below the eclipse calendar. It also is recorded in three
divisions agreeing closely with the eclipse calendar. One hundred and
thirty-five lunar months of 30 and 29 days complete 3986 days, .63 days
less than 135 synodical revolutions of the moon. This error which
amounts to more than one day when repeated once, necessitates the
addition of an extra day in the lunar calendar every other third, which
was done in the manuscript in the first and last third, making the total
recorded by the lunar calendar 11,960, two days more than the eclipse
calendar, and .11 days more than 405 synodical revolutions of the moon.
This period of 11,960 days may have been used as a cycle, the zero day
of which is 12 Lamat.
Each third of the lunar calendar consists of 30-and 29-day months
arranged in alternating sequence, with intercalary days added by the
substitution of a 30-day for a 29-day month when the error arising from
the nonconformity of the moon’s revolution reaches more than one day. In
order that the lunar calendar might agree with the eclipse calendar more
closely, these months were recorded in groups of five and six.
The months in each third of the series were divided into three groups,
which are the same in each third. The first two groups contained 47
months each, and completed the first sixteen dates of the third. The
last group was one of 41 months, which was represented by the last seven
dates of the third. An intercalary day was added in the 32d month of
each of the 47-month groups to correct the accumulating error, thereby
causing the 6th and 14th subdivisions of the third to be of 178 days. In
the first and last third the 40th month of the 41-month group also
contained an intercalary day for the same reason, making the 23d
subdivision 178 days, but in the last column of the record this extra
day is added by going from the middle to the lower line of day signs.
Each of the 47-and 41-month divisions began and ended with a month of
thirty days.
The numerical series of these pages of the Dresden record, then, an
eclipse calendar which is referred to a lunar calendar. This solution
explains all the irregularities of the series except those which seem
clearly to be clerical errors of the scribe.
Only the numerical and calendrical series on these pages have been
considered. No attempt has been made to explain the hieroglyphs, the
pictures, or the first two pages, which, although showing a close
association to the long series, are nevertheless a unit in themselves.