| RefNo | MA/256/4 |
| Previous numbers | MA.259 |
| Level | File |
| Title | Magnetic observations made at Port Louis, Falkland Islands, visited by HMS Erebus, by [James Clark Ross?] |
| Creator | Ross; Sir James Clark (1800-1862); polar explorer |
| Date | 21 July-28 November 1842 |
| Description | Daily magnetic observations made at Port Louis, 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 end-columns for thermometer readings and weather observations, usually wind direction and force. |
| Extent | 736p. [pp.240-736 blank] |
| Format | Manuscript |
| PhysicalDescription | Full vellum binding. Typed paper label to top of spine: 'Met. Arch. 259'. Inner front board has an engraved paper label: 'Jones & Causton, Wholesale Stationers...47 Eastcheap, Fish Hill Street...'. |
| Dimensions | 370x242mm. |
| AccessStatus | Open |