Balloon at Siege of Mainz. 19th-century illustration of a fixed (tethered) balloon used by Jean Marie Joseph Coutelle, commander of the first military balloon observation unit. 'Le Compagne d'Aerostiers' was created by King Louis XVI on 2 April 1794 and aeronauts were trained in balloon use. Observations by Coutelle of enemy positions helped to win several battles, such as this one at the 29 October 1795 siege of Mainz, Germany. The Aerostiers were disbanded in 1802. Artwork from 'Aerostation - Aviation' (1911) by French civil engineer Max de Nansouty (1854-1913), part of the 'Les merveilles de la science' series of 1867-1891 by Louis Figuier.