296 



supernumerary clay forms at the end of each indie- 

 lion a small entire period, and a tlalpilli contains 

 three hundred and sixty-five of these periods : 

 that is, as many weeks of thirteen days, as the 

 year has civil days. A year of the ritual alma- 

 nack has twenty half lunations, or two hundred 

 and sixty days, and this same number of days 

 contains fifty-two half decades, or small periods 

 of five days ; the Mexicans then found, in the 

 concordance of these two reckonings of the 

 Moon and the Sun, their favourite numbers of 

 five, thirteen, twenty, and fifty-two. A cycle of 

 fifty-two years contained one thousand four hun- 

 dred and sixty small periods of thirteen days ; 

 and, if to these we add thirteen intercalary days, 

 we shall have one thousand four hundred and 

 sixty-one small periods ; a number which acci- 

 dentally coincides with that of the years consti- 

 tuting the Sothiac period. 



The cycle of nineteen solar years, which cor- 

 responds to two hundred and thirty-five luna- 

 tions, and which the Chinese knew more than 

 sixteen centuries before Meton *, finds its multi- 

 ple neither in the cycle of sixty years, which is 

 in use among the greater part of the nations of 

 eastern Asia, and among the Muyscas of the 

 elevated plain of Bogota ; nor in the cycle of 

 fifty-two years, adopted by all the nations of the 



* La Place, Expos: torn. 2, p. 267. 



