n ETESIAN WINDS 175 



whereas, if its rise is to be traced to them, the river 

 ought to come from the same quarter as they do. 

 Furthermore, if it flowed out of the sea, its waters 

 would be clear and dark blue, not muddy, as they are. 

 Add to this that Euthymenes' evidence is refuted 

 by a whole crowd of witnesses. At such a time when 

 foreign parts were all unknown, there was oppor- 

 tunity for falsehood : people like Euthymenes had 

 scope for giving currency to travellers' myths. But 

 nowadays the whole coast of the sea beyond 

 Gibraltar is visited by trading vessels : none of the 

 traders tell us that the Nile rises there, or that the sea 

 in the Atlantic tastes differently from what it does 

 elsewhere. The very nature of the sea forbids 24 

 belief in the story that it is fresh : the freshest water 

 is always lightest, and as such attracted by the sun 

 in evaporation : the residuum, sea, must be salt. 

 Besides, why, on this theory, does the Nile not rise 

 in winter ? The sea may be raised at that season 

 by storms too, which are considerably greater than 

 the Etesians ; the latter are comparatively moderate 

 in their force. Besides if the source were derived 

 from the Atlantic Ocean, Egypt would be flooded 

 all at once ; but, as a matter of fact, the increase is 

 very gradual. 



Oenopides of Chios has another explanation : he 25 

 says that in winter heat is stored up under the 

 ground ; that is why caves are then warm, and the 

 water in wells is less cold. The veins of water are 

 dried up by this internal heat, he thinks. In other 

 countries rivers swell through rain : but the Nile, 

 being aided by no rainfall, dwindles during the 

 rainy season of winter, and by and by increases in 

 summer, a season at which the interior of the earth 

 is cold, and the frost returns to the springs. Now, 26 



