Caban. Yk.
Lamat. Ben. Edznab. Akbal.

5 deg.. _The Bissextile._

The connexion between the days or numbers of the week which designate
the beginning of the year, and the four initial or first days of the
series of five, is so intimate that it is very difficult to intercalate
an additional day for the bissextile, without disturbing that
correlative order of the initials which is constantly followed in the
denomination of the years, and forms their indictions, or weeks. But as
the bissextile is necessary to complete the solar course, and as I have
not any certain knowledge of the manner in which the Indians effected
that addition, I will exhibit the method adopted by the Mexicans, their
computation being very analogous to that of Yucatan, which in its
origin probably emanated from Mexico.

Veyta asserts, in ch. x. of his "Historia Antigua de Mexico," that the
bissextile was made by adding at the end either of the 18 months or of
the five supplementary days, a day which was marked with the same
hieroglyphic as the one preceding, but with a different number of the
week, viz., with the succeeding number. But in each way that numerical
order by which the years follow each other till they form the week of
years, is disturbed; since the fifth year would thus be designated by
the number 6 instead of 5, and the regular order of the years 4 to 6 be
thereby interrupted. These interruptions, recurring every fourth year,
would render it impossible to preserve that continuous harmony (on
which rests the whole system of the Indian computation) between the
numbers of the week which designate the ending year and its successor,
as shown in the uniform succession of the four initial days.

In order to prevent that inconvenience, it is necessary to suppose that
the Indians, whether they intercalated the additional day at the end of
the 18 months or after the five supplementary days, did not only give
to it the same number and hieroglyphic as to the day immediately
preceding, but also designated it by some peculiar sign or number, in
order that it might not be confounded with any other.

In a treatise published by Akerman, the opinion is expressed that the
Indians, at the end of their cycle of 52 years, added a week of days in
lieu of the bissextile days which had been neglected. This method has
not the defect of disturbing the numerical orde