A Meteorological Office open scale barograph specifically designed for marine use and made by one of the oldest surviving and world renowned instrument makers, Casella of London. The interesting 'harbour crane' movement was one of the very last intricate barograph developments by Casella, circa 1985 and later adapted for their standard size display barograph with a hardwood framed glazed case. Set in a sturdy white metal case, the superior movement is designed for shipboard use having enclosed oil damped diaphragms enabling a record of barometric pressure to be recorded with reduced interference from the ships roll or engine vibration. See extract from the Handbook of Meteororlogical Instruments. With 2 1/2 times the height of a standard barograph this instrument records very minor fluctuations in air pressure. The clock movement, by Gluck is to the specification originally developed and then standardized by the British Meteorological Office from the 1930s.
335mm wide x 177mm deep x 260mm high (hinged handle folded flat).