THOMAS] PREFATORY NOTES TO1 
not the same time or calendar system was used in all, and in what 
respect the system presented by Mr Goodman differs from that gener- 
ally understood and set forth by other writers—for if he is right 
in apprehending that previous investigators haye been at fault in 
regard to the Mayan time system, it is important, in view of future 
investigations, that this be clearly shown and the error be pointed out. 
A comparison of the time systems of the Maya, Nahuatl, and Zapotec 
tribes has been made to some extent from the historic standpoint. 
This comparison indicates that the time systems used by these tribes 
were substantially the same. 
As attention will be given almost exclusively to the examination of 
the time series and time systems of the codices and inscriptions, it is 
necessary, in order that the reader may follow closely and apply 
the tests himself, that the apparatus to be used be placed before him. 
This will involve some repetition of what has been given in my pre- 
vious papers; but in order to use Mr Goodman’s discoveries in com- 
parisons it is necessary to adopt some scheme of applying them which 
can be introduced here, as his tables cover more than 100 large quarto 
pages. This, I have found, can be done, after a little study and prac- 
tice, by means of two or three short tables, each occupying less than a 
page. They are therefore inserted with such explanations as are neces- 
sary to show how they are to be used. One of these tables which will 
be used in making comparisons is that numbered 3, on page 21 of my 
Maya Year,and entitled there ‘* Days and Months of the four Series 
of Years.” It is inserted here as table 1. 
