THE Handley Page aeroplane Gugnunc was presented to the Aeronautical Section of the Science Museum on July 19. On behalf of Lord Londonderry, Sir Christopher Bullock, in presenting the aeroplane, said that this machine marks a very distinct period in aviation, namely, the point at which safety in the air became one of the prime considerations as distinct from speed and carrying capacity. Mr. Handley Page's Gugnunc was built to participate in the Daniel Guggenheim International Safe Aircraft Competition held in the United States in 1929. Sir John Siddeley also presented the 150 horse-power Siddeley Mongoose air-cooled radial engine which is fitted in the Gugnunc. The aeroplane embodies the principle of the Handley Page slot which has been one of the most valuable contributions of British designers towards the security and safety of those who travel by air. The great enemy of the pilot, particularly in large machines, has been the ‘stall’, that is to say, there is a point at which the machine may be so far tilted backwards that it loses its power of lift and falls, sometimes uncontrollably, towards the earth. The great benefit derived from Mr. Handley Page's slot is that it enables the machine to fly at a much lower speed than normal before this danger point is reached. In fact, even after the machine has stalled, the pilot can retain control, and he does not fall into a dangerous dive or spin, but the machine sinks on a level keel. The slot has been adopted for the very large majority of aircraft used in the Royal Air Force as well as for private and commercial aircraft. In addition, 34 other countries use the device on military and civil aircraft. The designers have not yet exhausted the possibilities of the principle which is embodied in the Handley Page slot, and the technical staff both at the Handley Page works and at the Air Ministry have for a long time been engaged on research into the various possibilities arising out of this principle. The other two full-size machines in the Section are Wilbur Wright's machine, in which the first flights were made, and Alcock and Brown's Vimy which flew the Atlantic.