History is, strictly speaking, the study of questions.  —W.H. Auden, “Hic et Ille” (1956) In 1783, an unmanned hydrogen balloon was released from the area of Paris known as the Champ de Mars. It flew northwards for forty-five minutes, followed by chasers on horseback, and landed at the village of Gonesse, whose bemused inhabitants immediately attacked it with pitchforks. Later that year, before 400,000 spectators, two men in a balloon ascended to a height of nearly 2000 feet. They flew for two hours and covered a distance of thirty-six kilometres. The first military application of a hydrogen balloon occurred in…