This is an original liquid filled Cassens and Plath magnetic compass. The compass housing is 9 5/8 inches wide and about 5 inches tall. The gimbal ring is 11 1/2 inches wide. The compass is fully functional but looks to read several degrees off from a true North position. The liquid has a large bubble. The wooden box was made by us and makes a perfect display case. The wood box measures 16 x 16 inches and about 9 1/2 inches tall. This item weighs about 40 pounds.

Many types of fluid have been used over the years to fill liquid-damped compasses, such as this Cassens and Plath magnetic compass.  The presence of fluid acts to damp the horizontal circular oscillation of a compass card and allows the card to settle on north much faster than air-damped compasses.  Liquid-damped compasses traditionally have a floating compass dial that turns instead of a moving needle supported over a fixed card – but occasionally you will see exceptions.

A compass is an instrument used for navigation and orientation that shows direction relative to the geographic cardinal directions, or “points”. Usually, a diagram called a compass rose which shows the directions north, south, east and west as abbreviated initials marked on the compass. When the compass is used, the rose can be aligned with the corresponding geographic directions, so, for example, the “N” mark on the rose really points to the north. Frequently, in addition to the rose or sometimes instead of it, angle markings in degrees are shown on the compass. North corresponds to zero degrees, and the angles increase clockwise, so east is 90 degrees, south is 180, and west is 270. These numbers allow the compass to show azimuths or bearings.

This beautiful Cassens and Plath magnetic compass is indeed one of those nautical treasures that will add the final touch to your nautical collection.