One of the two captive hydrogen balloons of Coutelle's Compagnie d'Aerostiers (French Aerostatic Corps) deployed in 1795 during the unsuccessful siege of Mainz (Fr. Mayenne) by the French Revolutionary Army. Coutelle was the first military balloon observer using balloons to study enemy military movements. The tethered or captive balloon played an important role in air warfare such as reconnaissance, intelligence gathering and producing accurate battlefield maps. The position of a balloon is restrained by one or more tethers wound round the drum of a winch mounted on a vehicle. This was used to raise and lower the balloon.