thomas. I day COLUMNS IN THE DRESDEN CODEX. 23 



in the first month of the year. Hence if the five days of a column (as 

 of the Manuscript Troauo) are all taken from one side of the quadrilat- 

 eral of our scheme they will refer to years of one dominical sign only; if 

 alternately from opposite sides, then to the years of two dominical signs, 

 but if taken alternately from the four sides they would refer to the four 

 classes of years. This will reduce the number of dates in the Manu- 

 script Troano very considerably from the other supposition, but will not 

 in any way change the positiou of the Ahaues in the Grand Cycle. 



As one further item of evidence in regard to this method of arranging 

 the twenty days of the month in four groups or columns, I call attention 

 to what is found on Plate 32 of the Dresden Codex. Here we find the 

 four columns of five days each, corresponding precisely with the ar- 

 rangement of the Maya days into four groups, as heretofore. I present 

 here the arrangement as found on this plate : 



It will be seen by comparing this groupiug with that iu Table IV 

 that column a of this plate contains the same days as column 3 of the 

 table; column b the same as column 4; column c the same as column 1, 

 and column d the same as column 2. 



But so far I have found no entirely satisfactory explanation of the 

 order given iu many of these columns and in three of the sides of the 

 quadrilateral of the Cortesian plate. 



As this discussion is preliminary to a discussion of the assignment of 

 the symbols of the cardinal points, it becomes necessary, in order to 

 bring iu all the evidence bearing upon the question, to examine certain 

 points of the Mexican calendar system, as given by various authors and 

 as exhibited in the Mexican Codices. 



If we refer now to Plate 43 of the Borgiau Codex, as found iu Kings- 

 borough's " Mexican Antiquities," Vol. Ill, a photo engraved copy of 

 which is presented in our Fig. 4, we shall, as I believe, not only find ad- 

 ditional confirmation of the views I have advanced iu reference to the 

 peculiar arrangement of the days around the quadrilateral iu-the plate 

 of the Cortesian Codex, but also strong evidence of a common origin of 

 the Mexican and Central American calendars. 



This plate of the Borgian Codex, which is Mexican and not Maya, 

 consists of four groups, the whole arranged iu the form of a square ; each 

 group, also a square, is surrounded by a serpent, the heads of the four 

 serpents being brought near together at the center, which is indicated 



