148 THE PHYSICAL CONTEMPLATION OP THE UNIVERSE. 



nations which inherited their civilisation, new prospects and 

 a new outlet for maritime enterprises, it was also the means 

 of making known a fact by which the range of physical 

 ideas was more immediately enlarged. A great natural 

 phenomenon which, by the periodical upraising of the level 

 of the sea, renders visible the relations which connect the 

 Earth with the Moon and the Sun, now first permanently 

 arrested attention. When seen in the Syrtes of Africa, this 

 phenomenon had appeared to the Greeks accidental and 

 irregular, and had been sometimes even an occasion of danger. 

 Posidonius now observed the ebb and flood at Hipa and 

 Gadeira, and compared his observations with what the 

 experienced Phoenicians were able to tell him respecting 

 the influence of the Moon. ( 2I4 ) 



