174 EPOCHS IN THE HISTORY OP THE CONTEMPLATION 



guiding stars which conducted the human intellect securely 

 through the mazes of fanaticism in the dark ages; and did 

 not suffer healthy scientific intellectual power to perish. 



The mathematician and astronomer Eratosthenes of 

 Cyrene, the most celebrated of the Alexandrian librarians, 

 availed himself of the treasures at his command by working 

 them up into a systematic " universal geography." He freed 

 geographical description from mythical legends, and, al- 

 though himself occupied with chronology and history, even 

 separated from it the historical admixtures by which it 

 had been previously not ungracefully enlivened. Their 

 absence was satisfactorily supplied by mathematical con- 

 siderations on the more or less articulated form of continents, 

 and on their extent ; and by geological conjectures on the 

 connection of chains ot mountains, the action of currents, 

 and the former presence of an aqueous covering over the 

 surface of lands still bearing traces of having been once the 

 bottom of the sea. Regarding with favouj the oceanic sluice 

 theory of Strato of Lampsacus, the Alexandrian librarian was 

 ed by the belief of the former swollen state of the Euxine, 

 the disruption of the Dardanelles, and the consequent opening 

 of the pillars of Hercules, to the important investigation of 

 the problem of the equality of level of the " outward sea 

 encompassing all continents." ( 269 ) A farther instance of 

 happy generalisation on the part of Eratosthenes is his asser- 

 tion that the whole continent of Asia is traversed in the 

 parallel of Rhodes, (the diaphragm of Dicearchus), by a 

 tonnected chain of mountains running East and West. ( 2 ?) 

 A lively desire for generalisation, the result of the intel- 

 lectual movement of the period, also led Eratosthenes" to set 

 on foot the first (Hellenic) measurement of an arc of the 



