98 MEXICO AND CENTRAL AMERICA 



to be connected with the name for moon, u, and that the 

 hieroglyph for moon has the value, twenty, in the 

 inscriptions and ancient books. 



Before entering into a fuller discussion of the astro- 

 nomical and notational facts let us turn for a moment 

 to the third fact, the permutation system. The origin 

 of the cycle 1 known by the Mayan name tzolkin and the 



Chun 



§®§(3>©®§€ 



Fig. 35. The Twenty Day Signs. The first example in each 

 case is taken from the inscriptions and the second from the codices. 



Aztecan name tonalamatl, book of the days, has never 

 been satisfactorily explained. It is a permutation 

 system with two factors, 13 and 20. The former is a 

 series of numbers (1-13) and the latter a series of twenty 

 names as follows: — 



1. 



Imix 



6. 



Cimi 



11. 



Chuen 



16. 



Cib 



2. 



Ik 



• 7. 



Manik 



12. 



Eb 



17. 



Caban 



3. 



Akbal 



8. 



Lamat 



13. 



Ben 



18. 



Eznab 



4. 



Kan 



9. 



Muluc 



14. 



Ix 



19. 



Cauac 



5. 



Chicchan 



10. 



Oc 



15. 



Men 



20. 



Ahau 



'The word cycle is applied in this book to re-entering series, or wheels, 

 of days. These all contain the tzolkin or tonalamatl without a remainder. 

 The word period is applied to fixed numbers that do not contain the 



tonalamatl. 



