April. In the sixteenth century, the culmina- 

 tion of the Pleiades took place on the day of the 

 vernal equinox 3 h 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 calendar, all are in favour of 

 the system of Gama. I shall content myself with 

 citing a single proof. The Indian historiogra- 

 pher Christoval del Castillo, in a manuscript 

 work |, 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 Avas celebrated at the winter 



* Plin. Hist. Nat., Lib. 18, c. 25, (cd. Harduin, 1741,) 

 Tom, 2, p. 129. 



\ MSS., cap. 71. 



