An analysis of the Chinese and Mexican numerical systems likewise proves that their ultimate development was strikingly different, although it is easy to recognize how both might have arisen from the same source. Thus whilst the Mexican and Central American calendar (and social organization) is based on the combination of 20 characters with 13 numerals, the Chinese “took two sets of 12 and 10 characters respectively and combined them.” The outcome of the combination of 20 with 13 affords a marked contrast to that of 12 with 10. In the Mexican calendar, as I have shown, there were fixed periods of 5 days (associated with the Middle and Four Quarters) and of 20 days, the latter being “one complete count” of days, based on the primitive finger-and-toe count. In the Mexican social organization there were 4 principal and 16 minor clans of people, known by 20 signs. Each of these in turn was subdivided into 13 categories associated with the directions in space. By mentioning a sign and a numeral, up to 13, the exact subdivision of a clan was clearly designated while the direction of its residence, as regards the capital, was likewise conveyed. A day was associated with each of these 20 clans and their respective 13 subdivisions, and the unit of time produced by the combination of the 20 day-signs and 13 numerals was the period of 260 days, which held 4×65 days and was approximately equivalent to nine lunations and to the period of human gestation. The 260-day period, as will be more clearly shown in my monograph on the Mexican Calendar System, constituted the religious year of the “Sons or Lords of Night” in their cult of the Moon, the Nocturnal Heaven, Earth and the Female principle. Simultaneously with this lunar calendar, in which each moon had a different name, a civil or solar calendar was employed consisting of 365 days, divided into 17 periods of 20 and 1 period of 25 days. These years bore the names of four different signs in rotation combined with 13 numerals.(85) The cycles, thus produced, consisted of 4×13=52 years, 20, or a “complete count” of which, produced the great cycle of 1040 years.