Note 183 — Chapter IV · MEXICAN HIEROGLYPHICS—MANUSCRIPTS—ARITHMETIC—CHRONOLOGY—ASTRONOMY

The Persians had a cycle of one hundred and twenty years, of three hundred and sixty-five days each, at the end of which they intercalated thirty days. (Humboldt, Vues des Cordillèras, p. 177.) This was the same as thirteen after the cycle of fifty-two years of the Mexicans, but was less accurate than their probable intercalation of twelve days and a half. It is obviously indifferent, as far as accuracy is concerned, which multiple of four is selected to form the cycle; though, the shorter the interval of intercalation, the less, of course, will be the temporary departure from the true time.