wo years of retirement, devoted himself to the study of the
ancient chronology of Yucatan. It is a work which no ordinary man would
have ventured to undertake; and, if general reputation be any proof,
there was no man in the country so competent, or who could bring to it
so much learning and research. It adds to the merit of his labours
that, in prosecuting them, Don Pio stood alone, had none to sympathize
with him, knew that the attainment of the most important results would
not be appreciated, and had not even that hope of honourable
distinction which, in the absence of all other prospects of reward,
cheers the student in the solitary labours of his closet.

The essay explains at large the principles imbodied in the calendar of
the ancient Indians. It has been submitted for examination (with other
interesting papers furnished me by Don Pio, which will be referred to
hereafter) to a distinguished gentleman, known by his researches into
Indian languages and antiquities, and I am authorized to say that it
furnishes a basis for some interesting comparisons and deductions, and
is regarded as a valuable contribution to the cause of science.

The essay of Don Pio contains calculations and details which would not
be interesting to the general reader; to some, however, even these
cannot fail to be so, and the whole is published in the Appendix.[1] I
shall refer in this place only to the result. From the examination and
analysis made by the distinguished gentleman before referred to, I am
enabled to state the interesting fact, that the calendar of Yucatan,
though differing in some particulars, was substantially the same with
that of the Mexicans. It had a similar solar year of three hundred and
sixty-five days, divided in the same manner, first, into eighteen
months of twenty days each, with five supplementary days; and,
secondly, into twenty-eight weeks of thirteen days each, with an
additional day. It had the same method of distinguishing the days of
the year by a combination of those two series, and the same cycle of
fifty-two years, in which the years, as in Mexico, are distinguished by
a combination of the same series of thirteen, with another of four
names or hieroglyphics; but Don Pio acknowledges that in Yucatan there
is no certain evidence of the intercalation (similar to our leap year,
or to the Mexican secular addition of thirteen days) necessary to
correct the error resulting from counting the year as equal to three