SCIENCE AND CULTURE 125 



that day picked up the clue to her secrets exactly as it fell 

 from the hands of the Greeks a thousand years before. 

 The foundations of mathematics were so well laid by 

 them, that our children learn their geometry from a book 

 written for the schools of Alexandria two thousand years 

 ago. 8 Modern astronomy is the natural continuation and 

 development of the work of Hipparchus and of Ptolemy ; 9 

 modern physics of that of Democritus and of Archi- 

 medes; 10 it was long before modern biological science out- 

 grew the knowledge bequeathed to us by Aristotle, by 

 Theophrastus, and by Galen. 11 



We cannot know all the best thoughts and sayings of 

 the Greeks unless we know what they thought about 

 natural phenomena. We cannot fully apprehend their 



8 Euclid's Elements of geometry was written in the third cen- 

 tury B.C. Euclid was a Greek scholar who lived in Alexandria 

 during the reign of Ptolemy I. Alexandria, though in Egypt, 

 was for a time the centre of Greek learning, and was noted for 

 the fine library founded by Ptolemy I. 



9 Hipparchus (2nd century B.C.) was a Greek astronomer who 

 discovered the precession of the equinoxes, prepared a catalogue 

 of stars, founded astronomy, and invented the system of indi- 

 cating geographical positions by means of the circles of lati- 

 tude and longitude. Ptolemy was the famous Alexandrian as- 

 tronomer who gave his name to the system of astronomy which 

 first represented the earth as a globe and the planets as revolving 

 around it. 



10 Democritus, a Greek physical philosopher of the fifth 

 century B.C., is chiefly known for the atomic theory which he 

 expounded. Archimedes (B.C. 287-212) is said to have discov- 

 ered the principles on which the theory of specific gravity is based, 

 the Archimedean screw, and various burning devices and hurling 

 engines used in ancient warfare. 



11 Aristotle (B.C. 384-322) was a pupil of Plato and an im- 

 portant critic, logician, and moral and political philosopher. As 

 the creator of natural science he first divided the animal king- 

 dom into classes, and he came near discovering the circulation 

 of the blood. Theophrastus (B.C. 372-287) was a pupil of 

 Plato and Aristotle and was particularly interested in botany. 

 Claudius Galen (A.D. 130-200), a Greek physician, was regarded 

 until the sixteenth century as the greatest authority on anatomy 

 and physiology. 



