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ages should employ a very imperfect mode of 

 intercalation, might nevertheless maintain har- 

 mony between its calendar, and that of the most 

 civilized people, if, led by direct observation of 

 the heavenly bodies, it changed at times the begin - 

 ning of its year. The Mexican history, in its 

 annals, offers no trace of such sudden changes, 

 or extraordinary intercalations. Since the ce- 

 lebrated epoch of the sacrifice of Tlalixco, the 

 calendar had undergone no reform, the interca- 

 lation was uniformly made at the end of each 

 cycle ; and to explain how four centuries had 

 not been sufficient to produce a perceptible error 

 in the chronology, Mr. Gama admits, that the 

 Mexicans intercalated only twenty-five days 

 every cycle of a hundred and four years, cehue- 

 huetiliztli, or twelve days and a half at the end 

 of each cycle of fifty-two years, which fixes the 

 duration of the year to 365*24 days. He thinks 

 himself enabled to conclude from the statement 

 even of the historians of the sixteenth century, 

 that the secular festival was celebrated day and 

 night alternately ; and that, if the years of a 

 cycle began all at midnight, those of another be- 

 gan all at noon. Unable to examine the works 

 written in the Mexican language, I cannot de- 

 cide on the contrary of Mr. Gama's opinions. 

 The reasons which he alleges in his dissertation 

 on the monuments discovered in 1790, appear to 

 me less conclusive, since I have been enabled to 



