Before discussing this series it will be of advantage to review what the Codex gives us on the question of reading left to right or right to left.
First, in both the Dresden and Tro.-Cort. the glyph faces look to the left; and, as shown by the calculations, reading is from left to right, with a very few possible exceptions, such as the tables on Dres. 24, 64, 69, etc.
In the Perez, as shown by the tonalamatls on 15 to 18, the 52 year-bearers on 19 and 20, and the katun-series on 2 to 12, the general direction of the reading is also left to right.
Above or below each of the red number columns of these pages 23, 24, is to be found a blue number. These numbers make a katun-series, starting with 4, decreasing by 2, if we read it left to right. It is not, to be sure, accompanied by the customary Ahau-sign, [Hieroglyph], but, taken in connexion with the marked parallelism of the glyphs, face-tun glyphs and also others, on these two pages with those on pages 2 to 11, already discussed, the possibility that a katun-series is a part of this subject-matter must be considered.
On the other hand, the glyphs in the upper part of all four pages 21 to 24 face to the right, and, as already set out in detail, are practically all written in _reverse position_ as regards their prefixes, etc. And so also does the Eb-glyph in the day-columns we are now considering face to the right. These columns, unlike those on page 21, which include all of the 20 day-signs, only include 5 of the day-signs: Kan, Lamat, Eb, Cib and Ahau; Eb being the only non-symmetrical one of these.
We have thus quite strong evidence, especially as provided by the position of the prefixes, for a right to left reading, opposed by the direction of this katun-number series--if it be one. In Egyptian writing, of course, the direction of the reading changes with the facing of the figures.
To return now to the columns themselves, all the day-signs in any one column have each the same red numeral, so that we have: 8 Cib, 8 Ahau, 8 Kan, 8 Lamat, 8 Eb; and so on. The red numerals to each column also decrease by 2 towards the right, pari passu with the blue numerals. If we read each column downwards, it will form a closed circuit or round, returning into itself, with intervals of 104 days, from 8 Cib to 8 Ahau, etc., and again from 8 Eb back to 8 Cib. But if we next try to go to the next column, the series breaks, for from 8 Eb to 6 Lamat is only 76 days. We get a like break whether we read upward or downward, or right to left. Taking the columns separately then, the entire series (whether made up of 13, 20 or any other number of columns) cannot be made to read in one regular series, with a constant interval between the successive days of the whole.