BOOK II. xcix. 217-C. 219 



But all the tides cover and lay bare greater spaces occm luief 

 in the ocean than in the rest of the sea, whether (/'^'^^/'tv" 

 because it is more furious when moved in its entirety i"-'^^ ^tf^- 

 than when in part, or because the open extent feels 

 the force of the star " when it marches untrammeled 

 with more efFect, whereas narrow spaces hinder the 

 force, which is the reason why neither lakes nor 

 rivers have tides hke the ocean (Pytheas of Mar- 

 seilles states that north of Britain the tides rise 

 120 ft.) But also the morc inhmd seas are shut in 

 by land hke the water in a harbour ; yet a more 

 untrammeled expanse is subject to the tidal sway, 

 inasmuch as there are several instances of people 

 making the crossing from Italy to Utica in two days 

 in a calm sea and with no wind in the sails when a 

 strong tide was running. But these motions are 

 observed more round the coasts than in the deep 

 sea, since in the body too the extremities are more 

 sensitive to the pulse of the veins, that is of the 

 breath. But in most estuaries owing to the different 

 risings of the stars in each region the tides occur 

 irregularly, varying in time though not in method, 

 as for instance in the Syrtes. 



C. And nevertheless some tides have a special Exccpuotiai 

 nature, for instance the channel at Taormina ^ that ''"^''""'^'''" 

 ebbs and flows more frequently, and the one at 

 Euboea that has seven tides in twenty-four hours. 

 The tide at Euboea stops three times a month, on 

 the seventh, eighth and ninth day after the new 

 moon. At Cadiz the spring nearest the shrine of 

 Hercules, which is enclosed hke a well, sometimes 

 rises and sinks with the ocean and sometimes does 

 both at the contrary periods ; a second spring in the 

 same place agrees with the motions of the ocean. 



347 



