THE BELFAST ADDRESS. 145 



is in strict accordance with his philosophy, which was 

 severe and pure. 



2- 



Still earlier than these three philosophers, and 

 during the centuries between the first of them and the 

 last, the human intellect was active in other fields than 

 theirs. Pythagoras had founded a school of mathe- 

 matics, and made his experiments on the harmonic 

 intervals. The Sophists had run through their career. 

 At Athens had appeared Socrates, Plato, and Aristotle, 

 who ruined the Sophists, and whose yoke remains to 

 some extent unbroken to the present hour. Within 

 this period also the School of Alexandria was founded, 

 Euclid wrote his ' Elements ' and made some advance 

 in optics. Archimedes had propounded the theory of 

 the lever, and the principles of hydrostatics. Astron- 

 omy was immensely enriched by the discoveries of 

 Hipparchus, who was followed by the historically more 

 celebrated Ptolemy. Anatomy had been the basis of 

 scientific medicine; and it is said by Draper* that vivi- 

 section had begun. In fact, the science of ancient 

 Greece had already cleared the world of the fantastic 

 images of divinities operating capriciously through 

 natural phenomena. It had shaken itself free from 

 that fruitless scrutiny * by the internal light of the 

 mind alone,' which had vainly sought to transcend ex- 

 perience, and to reach a knowledge of ultimate causes. 

 Instead of accidental observation, it had introduced 

 observation with a purpose; instruments were em- 

 ployed to aid the senses; and scientific method was 

 rendered in a great measure complete by the union of 

 Induction and Experiment. 



What, then, stopped its victorious advance? Why 



* ' History of the Intellectual Development of Europe,' p. 295. 



