TIDES 



285 



HIGH TIDE IN THE BAY OF FUNDY. 



the day before, and that the time required for the comple- 

 tion of two high and two low tides is nearly 25 hours. Con- 

 tinued observation will 

 show, as Julius Caesar 

 stated many centuries 

 ago, that there is ap- 

 parently a relation be- 

 tween the phases of the 

 moon and the height of 

 the tides. The greatest 

 rise and fall of the water 

 will be found to occur 

 about the time of full 

 and new moon. 



The amount of rise 

 and fall of the tides is 

 not the same in different places. Upon shores of oceanic 

 islands the difference between high and low water, or 



the range, as it is called, 

 is not more than two or 

 three feet. In funnel- 

 shaped bays where the 

 tidal current is com- 

 pressed as it moves in 

 toward the bay head, 

 the range is very much 

 greater. In the Bay 

 of Fundy the range is 

 sometimes as great as 

 seventy feet. 



Sometimes these com- 

 pressed tidal currents 

 are formed at the mouths of rivers and move up the 

 rivers like a wall of surf several feet in height, en- 



Low TIDE AT THE SAME PLACE. 



