Magnetic variation observations at Barrack Square [Georgetown], Ascension Island, [South Atlantic Ocean], by Henry Foster and others Daily magnetic observations, in three columns, recording hourly position of the north end of the dip needle [degrees, minutes, seconds] at appointed observation times, with temperature in Fahrenheit. With a title page: 'Horary Variation of the Magnetic Needle Barrack Square Ascension. 1830'. Each page is headed: 'Increasing Readings denote North end going to the Eastward. Observations on the Diurnal Changes of a Magnetic Needle at Ascension'. 27 February-27 March 1830