THOMAS] MAYA METHOD OF CALCULATION 285 



This represents a calendar round or cycle of oi years (18,080 days), 

 tlie given date (3 Chicehan 18 Yax) returning at the end of this 

 period. For convenience we make the series ascending toward the 

 right, and after a few additions double tlie columns to make progress 

 more rapid. Tlic usual rule is followed; the cotinter is given as the 

 first column: the columns are numbered as a means of refe)-ence. 



(1) (2) (3) (4) (5) (6) (7) (8) (9) 



ooooooouo 



The counter or fii-st column is added to itself, or doubled, to form 

 the second; the first is added to the second to form the 3rd; the first 

 to the .Jrd to form Ihe -ith; but to hasten the process they are 

 doubled successively from tliis point to tlie 8th. As doubling the 8th 

 would raise the number above that contemplated, only the number 

 necessary to give the 9 cycles is added, but this miist be the counter 

 (first column) or a multiple of it. The reqiiired number is found in 

 the oth column; this added to the 8th gives the 9th. The sum of 

 the 9th column, if no mistake has been made, should, counting back 

 from 3 Chicehan 18 Yax, bring us again to the same date. 



As a count of a cj-cle of 52 years (our first column) includes the 

 entire series of days and day numbers known to the .system, 4 Ahau 

 8 Cumhu must be contained therein, and the count to it from the 

 date reached miist be less than the amount represented by our first 

 column. Our next step, tlierefore, is to ascertain the lapse oi time 

 from our last date (3 Chicehan IS Yax) to the next jireceding occur- 

 rence (as we are counting backward) of 4 Ahau 8 Cumhu. Just what 

 method the authors of the insci'iptions and codices emploj'ed for this 

 purpose, as there are more than one, I can not state positively, but 

 give one which I am satisfied they could follow. 



Tliey could readily ascertain, as is shown by almost every numeral 

 series with a date, tliat the day 3 Chicehan 18 Yax fell in tlie year 

 1 Laniat, and 4 Aliau 8 Cumhu in the year 8 Ben; hence they could 

 easily tell, by counting on their fingers or making marks, tliat from 

 the latter to the f(n'mer is 18 years and the fractions of the two years — 



the fraction in tlie foriiu'r being 198 days or. . . and in the latter 

 17 or ==:. As the year is represented by (", the 18 years would be . 



