1911 Encyclopædia Britannica/Dip

DIP (Old Eng. dyppan, connected with the common Teutonic root seen in “deep”), the angle which the magnetic needle makes with the horizon. A freely suspended magnetic needle will not maintain a horizontal position except at the magnetic equator. Over the N. magnetic pole the north-seeking end of the needle points directly downwards and dips at an intermediate angle at intermediate distances between the magnetic poles and equator. There are secular progressive variations of dip as well as of declination and the maxima are independent of each other. In 1576 the dip at London was 71° 50′, in 1720 (max.) 74° 42′, in 1900 67° 9′. (For Dip Circle see Inclinometer.)