131 
We have already observed^ that the Mexicans 
intercalated in a much more exact and regular 
manner, while the Peruvians rectified their lunar 
year from time to time by observations of the 
solstices and the equinoxes, made by means of 
cylindrical towers erected on the mountain of 
Carmenga near Cuzco % which served to take 
azimuths. 
Among the Muyscas, it is to the singular use 
of numbers, the series of which has two terms 
less than the rural year contains moons, that we 
must attribute the imperfection of a calendar, in 
which, notwithstanding the intercalation of the 
thirty-seventh month, ciihupqua^ the harvest, 
during six years, falls every year in a month of 
a different denomination. Thus the xeqiies an- 
nounced every year by what sign the month of 
the ears of maizQ should be presided, which cor- 
responds' to the Ahib or Nisan of the calendar of 
the Hebrews. As the power of a class of society 
is often founded on the ignorance of the other 
classes, the lamas of Iraca preferred an uncouth 
calendar, in which the eighth month (October) 
was sometimes called the third, sometimes the 
fifth; and in which the differences of season, 
sufficiently sensible as they are on the plain of 
Bogota, notwithstanding the proximity of the 
equator, did not coincide with the sunas of the 
^ Nieremberg, p. 139 ^ Cie^a, p. 230. 
K 2 
