| Description | Graphical representations made from hourly observations at Colaba Observatory, usually twelve of more days per sheet. Commencing with horizontal force [bifilar magentometer] and corrected barometer, with standard and ground thermometers. From September 1845, the sheets record additional magnetic instruments, for declination, horizontal force and vertical force.
Each sheet is headed 'Magnetic Observatory Bombay', with the commencing date of observations. Verso pages are usually blank, except p.2 and p22 which are inscribed 'Bombay Met Curves 1845-6'; p.4 has a rough pencil sketch map. |