TIDES AND WAVES 65 



feet on the other and how this is caused by 

 the tide being unable to flow out against the 

 wind and currents. In a lesser degree the 

 same thing occurs wherever a strong current 

 or wind prevails on our own coasts or where 

 a large bay or harbour is connected with the 

 sea by a narrow opening or channel. In such 

 places the water from the large bay cannot 

 flow out through the narrow entrance during 

 the six hours between high and low tides, 

 and hence the water inside does not rise and 

 fall the same amount as the tides themselves. 

 On the other hand, where there is a long, 

 narrow harbour or inlet connected with the 

 ocean by a broad estuary or strait the very 

 reverse happens. In such places the incom- 

 ing tide piles up as it proceeds between the 

 narrowing shores and produces an enormous 

 difference between the depth of water at high 

 and low tide. 



In the Bay of Fundy, Nova Scotia, the dif- 

 ference between tides is from fifty to sixty feet 

 and in the Bristol Channel about forty feet, 

 although on the shores outside of these bays 

 the real tide rises and falls only five or six 



