An ex- British Meteorological Office open scale marine barograph made by Casella, London. Met ref:1191, serial number MO6265/70 indicates the instrument was made in 1970. 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. With 2 1/2 times the height of a standard barograph this instrument records very minor fluctuations in air pressure.
Casella Large Marine Barograph