A.deviation B.variation C.compass error D.northerly error
A.the compass heading is in line with the lubber's line B.there is no lost motion in the gimbal rings C.no change of heading by compass is observed if you raise and lower the heeling magnet D.the gimbal rings do not strike the compass frame when they are tilted
A.The Flinders bar B.The heeling magnet C.Quadrantal soft iron spheres D.Bar magnets in the binnacle