Some writers have suspected, that the Mexi 
cans, before the reform of the calendar of Tla- 
lixco, had intercalated a day every four years. 
A festival of the god of fire (Xiuhteuctli), cele- 
brated with more solemnity in the year which 
bore the symbol tochtUy seems to have given rise 
to this opinion. Count Carli, whose American 
Letters exhibit a singular mixture of just obser- 
vations, of ingenious ideas, of mere sportive no- 
tions, and of things incompatible with the princi- 
ples of sound philosophy, and the true system of 
the motions of the heavenly bodies, imagines, that 
he has discovered, in the festivals of nine days, 
celebrated every four years, the remains of a 
lunar intercalation. He supposes, that the Mex- 
ican priests computed in a year twelve lunations 
of twenty-nine days, eight hours ; and that to 
bring back, every four years, these years of three 
hundred and fifty-two days to real lunar years, 
they added nine days. This supposition is al- 
most as vague as that of the same writer, when 
he attributes to the celestial bodies the mistake 
of the ancient calendars, in admitting that, some 
thousands of years before our era, the Earth 
finished its revolution round the Sun in three 
hundred and sixty days=^, and that a lunar 
month was only twenty-seven days and a half. 
* Lettres Americaines, tom. 2, p. 153, 161, 167, 333y and 
371. 
