Hydrogen gas production apparatus. 19th-century illustration of an apparatus used to produce hydrogen gas for balloons. The chemical reaction used is sulphuric acid with iron. The hydrogen is then washed and dried before use. This apparatus was designed by French engineer Gabriel Yon, and used during the First Italo-Ethiopian War (1895-1896) in Ethiopia (then known as Abyssinia). 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.