a 
98 MEXICO AND CENTRAL AMERICA 
book of the days, has never been satisfactorily 
explained. It is a permutation system with two 
900 08S 008 Se 
0209020008 
OO8a 2200086 
01200008008 
Fig. 37. The Twenty Day Signs of the Mayan Month. The 
first example in each case is taken from the inscriptions and thesecond 
from the codices. 
factors, 13 and 20. ‘The former is a series of numbers 
(1-13) and the lattera series of twenty namesas 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. Mulue 14. Ix 19. Cauac 
5. Chicchan 10. Oc 15. Men 20. Ahau 
These two series revolve upon each other like two wheels, 
one with thirteen and the other with twenty cogs. The 
smaller wheel of numbers makes twenty revolutions 
w hile the larger wheel of days is making thirteen revolu- 
tions, and after this the number cog and name cog with 
which the experiment began are again in combination. 
Thus, a day with the same number and the same name 
recurs every 13x20 or 260 days. 
This 260 day cycle corresponds to no natural time 
period and is an invention pure and simple. It is the 
most fundamental feature of the Mayan time count and 
of the time counts of other nations in Mexico and 
Central America. We may perhaps assume that the 
