282 THE POPULAR SCIENCE MONTHLY 



are several times referred to in extant orations. While they could be 

 used at any time of the day or night, they required constant attention, 

 and were by no means accurate. Generally the sun and the stars were 

 depended on when they could be seen ; for in the climate of Greece and 

 the adjoining lands there are fewer cloudy days and nights than in the 

 more northerly regions. In modern Athens about one half the days of 

 the year are entirely cloudless, and only thirty are noted as cloudy. 

 The Greeks used daylight almost entirely for business and rose very 

 early. A decree of Solon is often referred to which forbids teachers to 

 open school before daylight. For longer divisions of time the Greeks, 

 like most of the people of antiquity, depended on the moon, but they 

 never got the lunar months to correspond exactly with the facts. They 

 reckoned the month at twenty-nine and a half days, or one twenty-nine, 

 the next thirty. Their months, however, were not divided like ours 

 and the method of counting them so as to make them correspond with 

 the year was very complex, and the result unsatisfactory; there had to 

 be frequent corrections to make the seasons come at the same time of 

 the year. Yet nowhere in Greece was there ever discovered any way to 

 obviate the inherent defect of their clumsy system. In different parts 

 the months had different names, but were not divided like ours. There 

 is a passage in the " Clouds " of Aristophanes in which the moon is 

 represented as complaining of ill treatment because the Athenians had 

 allowed their calendar to fall into confusion to such an extent that the 

 gods were disappointed in their feasts. This made them angry with 

 the moon — very unjustly, since the confusion in their reckoning was 

 the people's fault. The case is very much as if we allowed our fourth 

 of July to drift about until it ultimately came in cold weather. The 

 lack of a fixed date for determining events gradually became generally 

 recognized; consequently, as is generally supposed, TimaBus, a Sicilian 

 Greek, proposed the Olympiads as an era. The Olympiads, however, 

 do not correspond with the era employed in Christian countries. Hence 

 we have to use a rule like the following : " Multiply the complete 

 Olympiads by four, and deduct the total from 776 for events of the 

 autumn and winter, or from 775 for events of spring and summer." 

 Although Timaeus flourished as late as 300 B.C., earlier dates were 

 made to correspond to his method of reckoning as well as it could be 

 done. It is probable that much of the older chronology is erroneous. 

 By means of observations taken on the star Sirius, both in Egypt and 

 Babylon as early as the fourteenth prechristian century, the year was' 

 found to be about 365| days in length. Those old-time astronomers 

 also reckoned by a lunar year of twelve months of 29 and 30 days alter- 

 nately. This was merely a concession to custom. The moon is such a 

 convenience for measuring periods longer than a day and shorter than 

 a year that the incongruity between its phases and the sun's motions 



