MORLEY] IXTEODUCTION TO STUDY OF MAYA HIEEOGLYPHS 277 



Beginning with the number 2,920 and the starting point 1 Ahau, 

 the first twelve terms, that is, the numbers in the three lowest rows, 

 are the first 12 multiples of 2,920. 



20,440= 7X2,920 

 23,360= 8X2,920 

 26,280= 9X2,920 

 29,200 = 10X2,920 

 32,120 = 11X2,920 

 35,040 = 12X2,920 



The clays recorded under each of these numbers, as mentioned above, 

 are the terminal dates of these distances from the starting point, 

 1 Ahau. Passing over the fourth row from the bottom, which, as 

 will appear presently, is probably an interpolation of some kind, the 

 thirteenth number — that is, the right-hand one in the top row — ^is 

 37,960. But 37,960 is 13x2,920, a continuation of our series the 

 twelfth term of wliich appeared in the left-hand number of the third 

 row. Under the thirteenth number is set down the day 1 Ahau ; in 

 other words, not until the thirteenth multiple of 2,920 is reached is 

 the terminal day the same as the starting point. 



With this tliirteenth term 2,920 ceases to be the unit of increase, and 

 the thirteeth term itself (37,960) is used as a difference to reach the 

 remaining three terms on this top line, all of which are multiples of 

 37,960. 



37,960 = 1 X 37,960 or 13 X 2,920 



75,920 = 2 X 37,960 or 26 X 2,920 

 113,880 = 3X37,960 or 39x2,920 

 151,840 = 4 X 37,960 or 52 X 2,920 



Counting forward each one of these from the starting point of this 

 entire series, 1 Ahau, each will be found to reach as its terminal day 

 1 Ahau, as recorded under each. The fourth line from the bottom is 

 more difficult to understand, and the explanation offered by Professor 

 Forstemann, that the fu'st and third terms and the second and fourth 

 are to be combined by addition or subtraction, leaves much to be 

 desired. Omitting this row, however, the remaining numbers, those 

 which are multiples of 2,920, admit of an easy explanation. 



In the first place, the opening term 2,920, which serves as the unit 

 of increase for the entire series up to and including the 13th term, is 

 the so-called Venus-Solar period, containing 8 Solar years of 365 

 days each and 5 Venus years of 584 days each. This important 

 period is the subject of extended treatment elsewhere in the Dresden 

 Codex (pp. 46-50), in which it is repeated 39 times in all, divided 

 into three equal divisions of 13 periods each. The 13th term of our 

 series 37,960 is, as we have seen, 13x2,920, the exact number of 



