'I hope these new mechanic meteors will prove only playthings ... and not be converted into new engines of destruction to the human race.' (Horace Walpole, 1785). Walpole's words were prophetic; within only eleven years the balloon had proved its worth at war and Joseph Montgolfier, even before a balloon had left the ground, had seen a potential use for his new invention in attacking the English at Gibraltar. The first 'air force' was founded by Napoleon Bonaparte. The American Civil, Franco-Prussian and First World Wars saw extensive use of balloons but it was during the Second World War that the balloon saw more new and imaginative uses. Barrage balloons helped prevent incursions by enemy aircraft and new, ingenious uses were found for balloons, including dropping bombs (as used by the Japanese against the USA), destroying enemy aircraft, espionage and other clandestine operations.