THE MEDITERRANEAN SEA. 255 



tures, however, admit of being converted into certainty ; and 

 doubtless will be so, with the augmented means which every 

 year affords for such researches. 



The common belief that the Mediterranean is a tideless 

 sea is not strictly true. It is too vast a basin not to feel in 

 itself, independently of those ocean tides which are almost 

 lost in the ingress of the Straits, that wonderful influence 

 of the moon and sun, acting by periods of endless inter- 

 mission on all the great waters of the globe. But neverthe- 

 less the surface is not large enough, nor the egress to the 

 Atlantic wide enough, to allow of those successive displace- 

 ments and replacements of water which are essential to the 

 complete phenomena of tides ; while the winds and the fluctua- 

 tions of atmospheric pressure, even more marked and frequent 

 here than on the ocean, have far greater effect in disturbing, 

 or annulling altogether, the slight tidal elevation actually 

 attained. It is only under certain local conditions, like those 

 which in the Bay of Fundy, the Bristol Channel, the mouth 

 of the Ganges, &c., raise the tides to forty or fifty feet, that 

 the waters of the Mediterranean show distinctly this in- 

 fluence. Wherever the line of coast is contracted into a 

 strait, or approximates to the funnel form, there the tide 

 generally becomes obvious. In the Faro of Messina it 

 rises from twelve to twenty inches, and occurs with some 

 regularity. At the northern extremity of the Adriatic, at 

 Venice and Chiozza, the rise often reaches two or three feet ; 

 greatly influenced by the winds of the gulf, but not depend- 

 ing on them. In the Grulf of Corinth similar but slighter 

 effects have been observed ; and again in the narrow Strait 

 of Negropont, the ancient Euripus, we find a very singular 

 and perplexing alternation of currents, partly, as it 

 appears, true lunar tides with periodical rise of waters, 

 partly the effect of irregular winds and of the tortuous lines 

 of mountain coast which mark this extraordinary locality. 



