Notebook of magnetic intensity observations made at Colaba Observatory, Bombay [Mumbai], India, by [Arthur Bedford Orlebar] Daily readings of vibrations and deflections using a [bar?] magnetometer, designated 'A51'. Columns for number of vibrations, time, difference, difference of 50 vibrations, bifilar, and torsion in an upper table, designated 'vibrations'; columns for deflection, reading, mean and difference, bifilar and torsion in a lower table, designated 'deflections'. With a monthly summary of results for April [p.29]. An unfinished table [p.30] gives the instruments in use as 'Vibrating A51. Deflecting A54''. The notes are paper bound, the front cover inscribed: 'Observations for Intensity for the month of April 1846. 1-30 April 1846