A compass that is described as “liquid damped” has the card immersed in a liquid that damps the rotation, so that the card settles faster making it both easier and quicker to read. Nearly all nautical compasses use liquid damping as do prismatic compasses and many baseplate compasses.
With older compasses, it is possible for the seal on the body of the compass to fail and the result is a loss of damping fluid with air taking its place. This failing is obvious on the baseplate compass below.
