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 highwater at that place. The interval (constant at any one place) may vary from 6 mins. (Harwich) to I I hrs. 45 mins. (North Foreland). At London Bridge it is i hr. 58 mins. (See TIDES.)