118 MEXICO AND CENTRAL AMERICA 
possibly refers to some astronomical event or discovery. 
In column C the long number does not lead to the 1 Ahau 
18 Uo that is given under it. ‘This date is reached by 
other calculations, however. At the base of A is a num- 
ber in three periods which,amounts to 2200. Not only 
is this the difference between the long numbers in B and 
C (1,366,560 — 1,364,360 = 2200) but, if we proceed for- 
ward 2200 days from the date given in B we arrive at a 
day 4 Ahau 8 Cumhu recorded under the number in A. 
In other words this number of days carries us forward to 
the end of the seventy-second calendar round after the 
original 4 Ahau 8 Cumhu (72x 18,980 = 1,366,560). 
Let us now make a new beginning in the lower left 
hand corner of this page. In G65 we find the number 
2920 which as we have already seen is exactly the number 
of days consumed in eight years of 365 days or five syno- 
dic revolutions of Venus of 584 days. We will now see 
how the Mayan scholars arrived at 13 x 2920 or 37,960, 
the calendar round of Venus. If we proceed towards the 
left in section 5 we find the second number, F5, is 5840 
which equals 2x 2920, the third is 8760 or 3x 2920, 
and the fourth is 11,680 or 4x 2920. The addition is 
continued in sections 4 and 3 till we reach 35,040 or 12 
x 2920. ‘To be sure the scribe made a slight error in one 
place, writing a 5 for an 8 but this is caught up by the 
day signs 9 Ahau, 4 Ahau, 7 Ahau, 12 Ahau, etc., that fall 
at regular intervals of 2920 days. 
From section 3, the calculation jumps to section 1 
where the numbers in the original are partly destroyed. 
They have, however, been restored with perfect assur- 
ance since the days in all instances are 1 Ahau and there- 
fore must be separated by multiples of 260 days. The 
number in G1 has been restored as 5-5-8-0 or 37,960 or 
13 x 2920. It contains 260 an even number of times 
and therefore every successive period of 37,960 days be- 
