he week
consisting of thirteen days, the month necessarily consisted of a week
and seven days; so that if the month began with the first number of a
week, it ended with the seventh number of the week ensuing.

[In order to know the number of the week corresponding with the first
day of each month respectively, it is necessary only to know the number
of the week with which the year begins, and to add successively seven,
but subtracting thirteen whenever the sum of this addition exceeds
thirteen, which gives the following series for the first days of the
eighteen months: 1, 8, 2 (15-13), 9, 3 (16-13), 10, 4, 11, 5, 12, 6,
13, 7, 1, 8, 2, 9, 3, supposing the first day of the year to be the
first day of the week, and generally taking for the first number of the
series the number of the week by which the year begins.]

4 deg.. _The Year._

To this day the Indians call the year _Jaab_ or _Haab_, and, while
heathens, they commenced it on the 16th of July. It is worthy of notice
that their progenitors, having sought to make it begin from the precise
day on which the sun returns to the zenith of this peninsula on his way
to the southern regions, but being destitute of instruments for their
astronomical observations, and guided only by the naked eye, erred only
forty-eight hours in advance. That small difference proves that they
endeavoured to determine, with the utmost attainable correctness, the
day on which the luminary passed the most culminating point of our
sphere, and that they were not ignorant of the use of the gnomon in the
most tempestuous days of the rainy season.

They divided the year into 18 months, as follows:

1st, Pop, beginning on the 16th of July.
2d, Uoo, beginning on the 5th of August.
3d, Zip, beginning on the 25th of August.
4th, Zodz, beginning on the 14th of September.
5th, Zeec, beginning on the 4th of October.
6th, Xul, beginning on the 24th of October.
7th, Dze-yaxkin, beginning on the 13th of November,
8th, Mol, beginning on the 3d of December.
9th, Dchen, beginning on the 23d of December.
10th, Yaax, beginning on the 12th of January.
11th, Zac, beginning on the 1st of February.
12th, Quej, beginning on the 21st of February,
13th, Mac, beginning on the 13th of March.
14th, Kankin, beginning on the 2d of April.
15th, Moan, beginning on the 22d of April.
16th, Pax, beginn