80 U. S. COAST AND GEODETIC SURVEY 
1 5 10 15 20 25 30 
Atlantic City 
Los Angeles 
Pensacola 
Fia. 38.—High waters, Atlantic City, Los Angeles, and Pensacola, October 1947. 
effects can be practically eliminated by subtracting from the height of high water the 
instantaneous height of sea level. The resulting heights of the high waters at the three 
stations for the same month of October 1947 are shown in Figure 39. The instantaneous 
height of sea level for any high water is derived by averaging the 24 hourly heights of - 
the tide which center about the time of that particular high water. 
The times of the moon’s phases, extreme declination and apogee and perigee are 
plotted at the top of Figure 39. The relation between the variations in the high waters 
and the moon’s position now becomes clear. At Atlantic City the variation is primarily 
