TIDES, WAVES 111 



their analogy in the ocean, and F. A, Forel 

 explained the currents in the Strait of Euripus 

 at Chalcis by assuming a seiche in the Talanti 

 Channel. Japanese observers have shown that 

 seiches exist in all well-defined bays in the 

 ocean, having a node at the mouth of the bay, 

 and a bell}^ at the head. The period of these 

 seiches is also susceptible of calculation, 

 given the shape of the bay. 



Many tidal phenomena could probably be 

 explained in this way. Certainly the small 

 embroideries on the records of tide gauges in 

 bays or enclosed areas of the ocean are 

 frequently due to seiches. But much longer 

 oscillations may possibly admit of similar 

 explanations ; the supposition that stations 

 where the range of the tide is very small are 

 near a node would explain many things. 

 But the problem regarded as one of standing 

 waves in limited oceans caused by lunar 

 attraction is much complicated by variations 

 in the intensity of the lunar attraction at any 

 one point on the earth's surface, and by the 

 rotation of the earth. Neglecting all such 

 complications, we see that the period of a 

 seiche in the Atlantic from Spain to Florida 

 might be about twenty-four hours, and a 

 binodal seiche about twelve hours. Tidal 

 records have not yet been examined care- 

 fully with this special object in view. 



