THE PRESIDENT'S ADDRESS. 365 



great progress has been made because the scientific mind has become 

 impressed with the necessity of, from time to time, examining every 

 received theory, in order to ascertain whether it is still in accordance 

 with facts. Thus, the phlogistic theory of chemistry promulgated 

 by Stahl and Beccher was replaced by the oxygen theory of Lavoisier, 

 when the discoveries of Scheele, Priestley, Cavendish and Black, showed 

 it to be no longer tenable ; and in our own day a very considerable 

 change in chemical theory and nomenclature has been made, because 

 the facts were found not to agree with deductions from the received 

 theory. Now, the Greeks did not neglect to observe facts, and in 

 truth, all the theories that they formed were based on facts. But 

 they had, as Buckle thinks the Scotch have, a strong bias towards 

 deduction, and having once made a generalization, their tendency was 

 • to reason from it and accept the results of this reasoning without 

 ascertaining whether they too were supported by the facts. From 

 this, also, resulted a great indistinctness and haziness in their expla- 

 nations of phenomena, even when they had by chance obtained some 

 glimmering of the correct view. As in the case of the giant who 

 received an accession of strength when he touched mother earth, it is 

 for the advantage of all fcheorizers to come down frequently to the 

 solid basis of reality. This tendency to deduction in the Greek mind 

 had, indeed, its good side. To it we owe the geometry of Euclid,, 

 which is the logical exhibition of the conclusions implicitly contained 

 in a few definitions, postulates, and axioms. In modern times there 

 has been a close alliance between the mathematicians and the devo- 

 tees of the sciences of observation and experiment, to their great 

 mutual advantage. But whatever may have been the cause, the geo- 

 metry of Euclid failed in ancient times specially to promote progress 

 in other sciences. 



While the failure of the Greeks to make any great advance in 

 this department has its lesson for us, the fact that they were the only 

 race of antiquity that made great and persistent exertions to solve 

 scientific problems has also its lesson. What was the cause of the great 

 intellectual activity of this race 1 T believe it to have been due to- 

 the same causes that made the Greeks free, whether these were 

 climatic, or racial, or connected with their occupation and mode of 

 life. As compared with Borne or Carthage, Athens and some of the 

 other great commercial cities of Greece were decidedly democratic,, 

 the Roman and Carthaginian populations having never been able ta 



