136 Springs, Rivers, and the Sea. 



time of high water the next day will be 

 about three quarters of an hour after noon; 

 the day following it will be at about half 

 an hour after one ; the day after that at a 

 quarter past two; and so on for thirty days 

 when it will again be found to be high wa- 

 ter at noon, the same as on the day the 

 observation was first made. And this ex- 

 actly answers to the motion of the moon ; 

 she rises every day about three quarters 

 of an hour later than upon the preceding 

 one; and, by moving in this manner round 

 the earth, completes her revolution in a- 

 bout thirty days, and then begins to rise 

 again at the same time as before. 



To make the matter still plainer ; sup- 

 pose, at a certain place, it is high water at 

 three o'clock in the afternoon, upon the 

 day of the new moon ; the following day 

 it will be high water at about three quar- 

 ters of an hour after three ; the day after 

 that at about half an hour past four ; and 

 so on, till the next new moon ; when it 

 will again be high water about three o'- 

 clock, the same as before. And by obser- 

 ving the tides continually at the same 

 place, they will always be found to follow 

 the same rule ; the time of high water, 



