Magnetic observations made at Port Louis, Falkland Islands [?] visited by HMS Erebus, by [James Clark Ross?] Daily magnetic observations made at Port Louis, or on board ship, using a declination magnetometer, a bifilar magnetometer, and a vertical force magnetometer. The readings are plotted against Gottingen mean time, at [most often] hourly intervals. With thermometer readings and an end column with occasional weather observations, usually wind direction and force. On 4 October 1842, the instrument readings are taken at more regular intervals, the occupying pp.9-25 of the volume. The volume gives no indication of the location of the observations, which must be inferred from earlier volumes in the series. 29 September-1 November 1842