INTRODUCTION. 9 



either plan must be broken to meet the exigencies of the solar course ; and when, as 

 in the Maya system, the first necessary interruption leads to a scheme of chronological 

 reckoning by periods other than years, succeeding irregularities are required to keep 

 the two calendars in touch from time to time and bring, after their vast sweep, all the 

 periods that have successively grown out of the diverging styles harmoniously back to 

 the common starting-point. The Mayas discovered that 13 was the most available 

 number to use in connection with 20 for these purposes, hence its adoption ; but 

 wherever it appears throughout the whole scheme it is always subordinate to its 

 imperial consort. Either, however, would be ineffectual without the other. It is in 

 their combination that the Maya genius is shown — a genius that in remote isolation 

 elaborated a chronological system whose perfection cannot fail to excite our admiration 

 and wonder though standing in the focused light of all the ages and civilizations. 



BIOL. CENTR.-AMER., ArchsEOl. 



