Balloonophiles must nurse a particular affection for Wolverhampton, for it was from there that, on 5 September 1862, one of the most celebrated ascents began. The pilots were James Glaisher, secretary to the Royal Meteorological Society, and Henry Coxwell, whose claim to scientific knowledge derived from his former career as a dentist, but who was a seasoned balloonist and, as it transpired, a good man to have in a tight spot. The balloon left the ground at one o’clock in the afternoon, filled with buoyant coal gas from the Wolverhampton gasworks. It was a beautiful day and they climbed quickly: forty minutes later they were past 20,000 feet; just before an hour was done they were at 29,000 feet. Then they hit a snag.