Mean Low Water Springs

Maximum Level of Water Spring

Mean Level of Water Springs

Mean Level of Water surface

Ranging

Fixing

Plotting

Sighting

Gross time

Age of tide

Net time

Mean time

Attractive force between earth and celestial bodies

Attractive force b/w the celestial bodies

Attractive force between sun & moon

Attractive force with in the earth

Altimeter

Height indicator

Tide gauge

Pressure gauge