as Seler has shown, we will repeat that the elements of this central part of the magnificent relief are glyphs symbolical of special cycles and of complete years; but in no case of days. These find their representation by means of dots upon the bodies of the serpents and with their own proper characters in the zone outside the sun's face; the other characters of the central part of the stone possess a much larger significance, in consonance with the importance of the monument. The objects of this kind that deal with the representation of a simple year are very few; usually the natives figured knottings or tyings and the cycle of 52 years, which appears with great frequency in the codices and in the inscriptions of stone. It happens thus in the tableland of Mexico the same as in Yucatan; in Mitla and Xochicalco as in the zone of Palenque, Copan, and Quirigua. With greater reason may we suppose analogous meaning in a colossal relief, which is but the Teoamoxtli made stone or the allegory of the world's history, conformable to the cosmogonic and astronomical beliefs of the aborigines. It is obvious that, in an allegory of this kind, the component elements should represent periods of a certain duration.
Let us undertake now to explain rationally the necessity of inscribing four groups of Venus cycles in place of one, since one suffices to indicate the century of the chronological counts, 104 years. We might limit ourselves exclusively to facts, indicating the pages already mentioned of the Borgian, Vatican B, and Fejervary-Mayer codices, which show the frequency with which the native astronomers reputed in their pictographs what we see in the basalt relief. Also the Dresden Codex gives the number of 151,840 days, which are 260 Venus years. But we must explain the data which are observed. The reason of the fact reveals how perfect were the astronomical observations of the ancient inhabitants of America, and to what height their knowledge of the phenomena of space attained. The value of the apparent revolution of Venus not being exactly 584 days, but 583 days 22 hours, 6 minutes, and 14 seconds, it seems that the natives knew this difference, at least as regards the 22 hours over and even a little more. In the development of the series of days, it results that at the end of 104 years (65 Venus years) the calendar of the planet was five days behind with reference to the solar; and the Indians, proceeding as astronomers, had to make some correction. This was secured by initiating in a special calendar (probably reserved for chiefs and priests, and but little known to the vulgar) the second huehuetiliztli, with another five of the twenty day
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