388 
April. In the sixteenth century, the culmina- 
tion of the Pleiades took place on the day of the 
vernal equinox 3^ 8' before the setting of the 
Sun. It is true, that, according* to an ancient 
tradition *, the disappearance of this constella- 
tion at sunrise denoted formerly the day of the 
autumnal equinox, which supposes an observa- 
tion made three thousand years before our era ; 
but we cannot admit, that the Mexicans had re- 
ceived their chronology from a people, who be- 
gan their year at the entrance of autumn. The 
concordance of dates, several astronomical phe- 
nomena, the evidence of the Spanish authors 
who accumulated materials without knowing the 
true system of the calendai*, all are in favour of 
the system of Gama. I shall content myself with 
citing a single proof. The Indian historiogra-^ 
pher Christo val del Castillo, in a manuscript 
workf, written in the Mexican language, and 
preserved at Mexico, asserts, that the five com- 
plementary days were added to the end of the 
month Atemoztli ; which corresponds, according 
to the unanimous testimony of the Indian and 
Spanish authors, to our month of December. 
Torquemada says besides, that the third festival 
of the god of water was celebrated at the winter 
* Plin. Hist. Nat., Lib. 18, c. 2&, (ed. Harduin, 1741,) 
Tom. 2, p. 129. 
i MSS., cap. 71. 
