THE BEGINNINGS OF KNOWLEDGE 11 



tians are believed to have learned mensuration and 

 started the science of "earth measurements, " or geom- 

 etry, because of the necessity of marking anew each 

 year the boundaries of fields flooded by the Nile. They 

 did not carry their development, however, beyond the 

 simple ideas necessary to lay off plots of ground and 

 to compute areas and volumes. It was left for the 

 Greeks to develop later the abstract ideas and general 

 methods of reasoning which we know to-day as geom- 

 etry. 



Both these peoples were highly religious. With 

 then- lack of scientific knowledge it was but natural 

 that they should be superstitious about the stars, and 

 that their knowledge of astronomy should develop hi 

 connection with their religion. To the Babylonians 

 we apparently owe the grouping of days into longer 

 periods called weeks. Why seven days were chosen 

 for the latter period is evident from our names for these 

 days, which are traced in derivation to the sun, the 

 moon, and the five planets, Jupiter, Mercury, Mars, 

 Venus and Saturn. 1 The lunar month was of course 

 early noticed and measured by these astronomers. 

 They had also progressed far enough to measure the 

 year as 365i days and to determine other astronomical 

 facts. 



These facts were developed in connection with their 

 religion and their practical needs. In Babylonia, 

 where stone was not easily obtainable and brick was 

 used for building, one of the months was named for 

 the brickbuilders. In this month, apparently, the 



1 Cf. Libby, "An Introduction to the History of Science," 

 Houghton Mifflin Company, 1917. 



