168 THE GREEK ASTRONOMY. 



stripes or zones into which the earth's surface was 

 thus divided. In going to the south, Europeans 

 found countries hotter and hotter, in going to the 

 north, colder and colder; and it was supposed 

 that the space between the tropical circles must 

 be uninhabitable from heat, and that within the 

 polar circles, again, uninhabitable from cold. This 

 fancy was, as we now know, entirely unfounded. 

 But the principle of the globular form of the earth, 

 when dealt with by means of spherical geometry, 

 led to many true and important propositions con- 

 cerning the lengths of days and nights at different 

 places. These propositions still form a part of our 

 Elementary Astronomy. 



Gnomonick. Another important result of the 

 doctrine of the sphere was Gnomonick or Dialling. 

 Anaximenes is said by Pliny to have first taught 

 this art in Greece ; and both he and Anaximander 

 are reported to have erected the first dial at Lace- 

 demon. Many of the ancient dials remain to us; 

 some of these are of complex forms, and must 

 have required great ingenuity and considerable 

 geometrical knowledge in their construction. 



Measure of the Suns Distance. The explana- 

 tion of the phases of the moon led to no result so 

 remarkable as the attempt of Aristarchus of Samos 

 to obtain from this doctrine a measure of the dis- 

 tance of the sun as compared with that of the 

 moon. If the moon was a perfectly smooth sphere, 

 when she was exactly midway between the new 



