THE ENVIRONMENT 39 



The science of cosmography is probably 

 the earliest of all the natural sciences, and 

 cosmological speculation appears to accom- 

 pany it from the outset. Long before the 

 dawn of history the Chaldeans possessed 

 much accurate information about the stars, 

 and the zodiac was known to the Egyptians 

 not less than fifteen centuries before our era. 

 Always pursued with great interest, such studies 

 received their first provisional systematic for- 

 mulation at the hands of Hipparchus in the 

 second century B.C. He, the greatest of the 

 astronomers of antiquity, succeeded in bring- 

 ing the apparent movements of the sun, moon, 

 and planets into an arbitrary scheme which 

 was nearly perfect for the sun, though less 

 so for the other movable celestial bodies. He 

 also measured and catalogued the positions 

 of a large number of fixed stars. Upon this 

 secure foundation of quantitative observa- 

 tions modern astronomy has built. At the 

 beginning of the modern period Copernicus, 

 Tycho Brahe, Kepler, Galileo, and Newton 

 reduced the phenomena of the_ solar system 

 to jav£ At a l ateT~liayHspeculations based 

 upon their results and upon growing knowl- 

 edge of physics and chemistry led Thomas 

 Wright, Kant, and finally Laplace to a ra- 

 tional, if somewhat imperfect, cosmological 



