Magnetic variation observations at Lemon Valley, St. Helena, [South Atlantic Ocean], by Henry Foster and others Daily magnetic observations, in three columns, recording appointed observation times, then four sets of measurements of arc, vibration [zero to 300], 'times 699', intervals in seconds and temperature [in Fahrenheit]. With tables of hourly timings from each day [8-26 January] in seconds, of the magnetic dip needle performing 300 vibrations, with totals and means. With a title page [p.7]: 'Intensity. Lemon Valley St. Helena.' Each page is dated and headed: 'Observations on the Diurnal Changes of Magnetic Horizontal Intensity at Lemon Valley St. Helena'. The concluding tables are styled: 'Table exhibiting the time of a Magnetic Needle performing 300 vibrations between the Arcs of 40 degrees and 11 degrees at the undermentioned hours and temperatures, Lemon Valley St. Helena'. 8-28 January 1830