De Rosny has given in his "Compte-Rendu d'une Mission Scientifique," published in the "Mémoires de la Société d'Ethnographie," an admirable reproduction of the wooden inscription which came from Tikal. On Plate 12 of this work we find on A B 1, 3 Ahau 3 Mol, and on B 2 A 3, we have 2.11.12. By counting forward this number of days from 3 Ahau 3 Mol we reach 6 Eb 0 or 20 Pop, if the month begins with 0 or 20, but 6 Eb 5 Uayeb if the month begins with 1. This is a particularly strong case, for the month is surely Pop and the number is certainly not 5, and is like those of the manuscripts and of the Temple of the Cross, which we have just commented on and which are in all probability 0 or 20.
Again, on a part of a doorway in El Cayo, on C D 3 we find 13 Cimi 19 Zotz; on H 3 G 4 is a number which seems to be 8.18.6. Counting forward we reach 9 Eb 20 Uo, if the month begins with 1, or 9 Eb 0 or 20 Zip, if the months begin with 0 or 20. Although the glyphs for Uo and Zip resemble each other, yet the date on I J 1 is clearly 9 Eb 0 or 20 Zip. It should be said, however, that the number on H 3 G 4 is somewhat effaced and very unusual, in showing 18 uinals, and that there is another date 5 ? 3 Yaxkin on E F 3.
On the other hand the inscription of the Temple of the Cross shows us on D 3 C 4, 4 Ahau 8 Cumhu, and on D 5 C 6, is 1.9.2., which is equal to 1 year 177 days. Counting forward this number of days from 4 Ahau 8 Cumhu we reach 13 Ik 20 Mol, if the month begins with 1, or 0 or 20 Chen, if the month begins with 0 or 20. On C D 9 we find 13 Ik ? Mol. However, on D 13 to C 15 we have the long number 1.18.3.12.0., which counted forward from 13 Ik 20 Mol brings us to 9 Ik 15 Zac, which is not found anywhere near by. But if we count forward this number from 13 Ik 0 or 20 Chen, we should reach 9 Ik 15 Ceh, which is found on E F 1. It would seem, therefore, that the glyph for Mol had been carved in error for that of Chen.
Other cases where 0 or 20 probably occur before the month sign are the following:
| Copan, Altar | U, 1 to 2 | 2 Caban | 0 or 20 Pop. |
| " " | U, 51 to 52 | 3 Eb | 0 or 20 Pop. |
| Temple of the Cross, | Q 2 P 3 | 11 Caban | 0 or 20 Pop. |
| " " " " | F 12 E 13 | 9 Ik | 0 or 20 Chen (J.T.G.) |
| " " " " | E F 9 | 9 Ik | 0 or 20 Yax or Zac. |
The month glyph of the last example looks like Zac. If it is Yax it proves Goodman's theory by calculation.
Thus we see that in three out of four cases in the Dresden Codex and in three cases out of four in the Inscriptions where the context is such as to throw light on the question, the evidence is in favor of concluding that the months began with a day 0 or 20 and not with a day 1. Moreover in the single case in the Codex which tends to prove the contrary, it is interesting to see that the month glyph, Xul, is somewhat different from the other Xul glyphs, while in the doubtful case in the inscriptions, if the month glyph had been Chen and not Mol, it would have agreed with the dates before and after it. In other words, the calculations both before and after the date in question would be quite accurate if the month were Chen and if, therefore, the beginning day were 0 or 20, while the glyph of Mol makes the calculation after that date inaccurate.
All the evidence taken gives a very strong presumption in favor of Goodman's theory that the month began with 0 or 20.
It is also interesting to notice that of the other dates given above where the calculation does not help us, three of these are 0 or 20 Pop (provided we have identified the number glyph correctly, which is certainly none of the known glyphs for any of the numbers 1 to 19). This date would not be significant if 20 Pop were the last day of the month, but it would be very significant if it were the beginning day of the month, that is the beginning day of the New Year. I think, therefore, that it is safe to assume as a good working hypothesis that the beginning days of the month were designated as 0 or 20, and the last day of the month as 19.
The second of our questions,—namely, whether this beginning day was called Day 0 or Day 20,—must now be taken up. Of course if we had decided that those cases which we have been considering represented the last days of the month, there would have been no question that the number glyphs which were not any of the numbers from 1 to 19 must be the number 20. It would have been very improbable that after having numbered the days of a month from 1 to 19 they would have called the last day 0. But it is not as certain that they might not have called the beginning day of a month 20, considering that twenty days had passed of the preceding month, and that their count was regulated by the number of days which had passed. As far as the month dates are concerned, however, it is absolutely unimportant whether the beginning day is called 0 or 20. Goodman says that the Mayas had no need of a zero (following the Romans in this respect), since zero was of no use as a multiplier. This is hardly conclusive. It may be true, as Goodman says, that the Mayas in their month dates spoke of the twenty days which had passed in the preceding month; but it is equally true that they may have expressed this idea by attaching the number zero to the beginning day on the ground that no days of the current month had elapsed. Indeed the latter explanation is the more credible, since, if they had spoken of the twenty days of the preceding month as having elapsed, it would seem possible at least, and perhaps probable, that they would have used the name of the preceding month as well, and would have called the beginning day of Yaxkin, for instance, 20 Xul and not 20 Yaxkin. But this it seems they did not do, unless the instance on the Temple of the Cross and that of the Dresden Codex, already cited, would bear this construction. These instances, however, are contradicted by all the other cases and are themselves capable of a different interpretation. It would seem as if the Mayas probably called the beginning day of a month by the name of the current month, and that they attached the zero to it, meaning that no days of that month had elapsed. Moreover such a plan is very much easier for calculation and there is less liability to error; for it is natural to think of a day with the number 20 as following a day with the number 19 and as being the last day of a month containing 20 days, rather than the beginning day of a month. I do not place too much reliance on this, however, for it is hardly safe to argue back from what we at this time would consider the best thing to do, in order to find out what some other nation at some other time would have done.