3.1 THE PARIS EXPERIMENTS Skeptics had claimed that Brown’s flying discs were propelled entirely by ion wind pressure and would lose their propulsive force if tested in a vacuum chamber where few air molecules would be present, hut in 1955 and 1956, they were proved wrong. Under the sponsorship of the French government, Brown conducted a series of vacuum chamber experiments at facilities made available by Société Nationale du Constructions Aeronautiques du Sud-Ouest, a Paris-based aeronautical corporation. There, he successfully flew a pair of miniature saucer airfoils in a high vacuum of less than one billionth of an atmosphere. Not only did the discs propel themselves more efficiently, hut they also sped faster, since, without ion leakage, they could be energized with greater voltages. The tests used a 200-watt power source to supply DC potentials rangi ng from 70 to 220 kilovolts) Few details are known about these tests because the results were considered a confidential matter. However, it appears the discs measured about 4 to 5 inches in diameter and had a central body made of solid aluminum.2’ By comparison, the 1.5- and 3- foot-diameter discs that Brown had tested in his carousel demonstration svere made of Plexiglas and lightweight sheet aluminum.