The barometric tube is fixed to a wooden board and runs down into a vessel serving as a cistern for the barometer. There is a screw for vertical adjustment of the vessel. An ivory indicator determines the height that needs to be reached by the mercury in the vessel to take correct readings. The barometric scale is divided into millimeters and engraved on the glass tube. It has a small sliding metal tube serving as a vernier. The top part of the tube holds a container, possibly for ice to minimize the pressure of the mercury vapor. The thermometers that originally came with the instrument are missing.