ASTRONUiVJCAL SCIENCE IN THE ANCIENT ORIENT 201 



Since a month of 29 or 30 days is rather too long to be used as 

 a convenient interval for 2)riniitive life, it is quite natural that a 

 mode of dividing it into three or four parts was soon adopted in these 

 old days. The mode of dividing a lunar month into four quarters 

 seems to have been widely in use in western Asia, and it is generally 

 accepted that the present use of weeks in almost all civilized countries 

 is nothing but a modified or improved form of the ancient lunar 

 quarters. In China also, we suspect that there was some trace of the 

 use of lunar quarters about the beginning of the Chou dynasty ; their 

 use, however, seems not to have been general. 



The mode of dividing a lunar month into three decades was in 

 general use in the Orient until recently, the trisected part of 9 or 10 

 days being called lisun ^. The ten ordinals, or cAm i ping ting onou 

 chi king hsin jen kuei ^^p^Tj[3cEIi^$i^j usually known as the 

 " Ten stems " -f^^, whose original meaning is almost lost in oblivion, 

 can be nothing but the ordmals marking the days of a decade (^)- 

 We see, indeed, that the ten ordinals were called ''Ten days" -j^g 

 in the older classics, the nomination " Ten stems " -j^^ being no 

 earlier than the Han dynasty ^ (206 B.C. -221 A.D.) 



3. The C/i'en ^, or Standard Asterisms. 



The steady increase of population soon necessitated the production 

 of provisions in abundance ; and since this could be effected only by 

 the systematic cultivation of food-plants, utilizing in fact the seasonal 

 variations to the utmost, the preparing of a good solar calendar 

 became an urgent necessity. The date of the first introduction of the 

 solar calendar probably corresponds to the time of the sacred but at 

 the same time somewhat fabulous emperors Yao ^ and Shun ^, 

 which is estinjated to fall at about the 24th century B.C. 



As the length of a tropical year was not at all known at that 

 remote age, the only reasonable way must have been to determine the 

 seasonal epochs by observing certain cardinal asterisms just after sunset 

 or just before sunrise. Thus the Egyptians used to observe the helia- 

 cal rising of Sirius, and the Chaldeans the same of Capella, as means 

 of fixing the beginnings of their respective agronomical calendars. 



In China, many such asterisms seem to liave been in use, 

 probably in different localities, or in difterent ages, all being called 

 by the name of ch'en ^, or standard asterism. We can trace at least 



