This cistern barometer is called "marine" because it could be installed on a ship by means of gimbals fastened to a wall to ensure verticality. The instrument is housed in a wooden tube. There is a screw under the cistern to adjust the mercury level. The barometric scale, in English inches, is engraved on brass and has a vernier. Under the scale is a brass ring nut with two vertical pivots for inserting the instrument in the gimbals. Above the barometer is a tube on which a counterweight slides friction-tight: the barometer could therefore move in its suspension to offset the ship's motion. A mercury thermometer with Réaumur and Fahrenheit scales is fixed to the wooden tube. Made by Worthington & Allan.