1911 Encyclopædia Britannica/Establishment of a Port

ESTABLISHMENT OF A PORT, the technical expression for the time that elapses between the moon’s transit across the meridian at new or full moon at a given place and the time of high water at that place. The interval (constant at any one place) may vary from 6 mins. (Harwich) to 11 hrs. 45 mins. (North Foreland). At London Bridge it is 1 hr. 58 mins. (See also Tide.)