A French wheel barometer in the shape of a cartel, c. 1780 The Louis XVI case is made of wood and is partly painted and partly gilded. The painted dial shows the air pressure in French inches. The dial is protected by a convex glass, which contains a central setting hand. At the back there is a mercury tube from which the mercury level is transferred to a pulley to which the hand is attached. Thus the air pressure is shown on the scale. The barometer is signed by the maker Par Gobin Constructeur d'instruments de physique rue Neuve Dustache no 19 à Paris The barometer is in very good condition.