Yves le Prieur Yves Paul Gaston Le Prieur ( March 23 , 1885 – 1 June 1963 ) was an officer of the French Navy and an inventor . Adventures in the Far East . Le Prieur followed his father in joining the French navy . As an officer he served in Asia and used traditional deep sea diving equipment . He studied Japanese and became sufficiently proficient to be promoted to military attaché and translator at the French Embassy in Tokyo . While there he became the first Frenchman to earn a Black Belt in judo , and the first person to take off in a plane , a glider , from Japanese soil in 1909 . The glider , named Le Prieur No . 2 after an earlier No . 1 unmanned prototype , was 7 . 2 m long , 7 . 0 m wide , and weighed 35 kg . The frame was made of Japanese bamboo , which was covered with calico . Le Prieur had designed the glider in collaboration with Shirou Aibara , a Lieutenant of the Japanese Navy , and Aikitsu Tanakadate , a professor at Tokyo Imperial University . The first flight took place in December 1909 just to the East of the University of Tokyo at Shinobazu Pond with Le Prieur sitting on the glider ' s main wing . The first flight covered 200 m at an altitude of 10 m . First World War . During the First World War he invented the plane - mounted Le Prieur rocket launcher for bringing down observation balloons . Le Prieur also patented a number of designs for mechanical lead computing sights for both ship to ship and anti - aircraft guns . Invention of Scuba . In 1925 Le Prieur saw a demonstration at the Industrial and Technical Exhibition in Paris of a diver using a breathing apparatus invented by Maurice Fernez . The Fernez breathing apparatus consisted of a simple T - shaped rubber mouthpiece . On one side this was connected to a long tube down which air was pumped from the surface . On the other side of the mouthpiece , excess and exhaled air escaped from a simple rubber " ducks bill " valve . The diver ' s nose was pinched by a pair of spring clamps ( " pince nez " ) to prevent ingress of water , and his eyes were protected by small goggles with rubber surrounds . Le Prieur was impressed by the simplicity of the Fernez equipment and the freedom it allowed the diver , and he immediately conceived an idea to make it free of the tube to the surface pump by using Michelin cylinders as the air supply . Michelin cylinders contained three litres of air compressed to 150 kg / cm2 supplied by Michelin to garages without air compressors for inflation of car tires . Le Prieur approached Fernez , who cooperated to modify his equipment to Le Prieur ' s idea , and on 6 August 1926 the " Fernez - Le Prieur " diving apparatus was demonstrated at the swimming pool of Tourelles in Paris . The unit consisted of a cylinder of compressed air carried on the back of the diver , connected to a pressure regulator designed by Le Prieur adjusted manually by the diver , with two gauges , one for tank pressure and one for output ( supply ) pressure . Air was supplied continually to the mouthpiece and ejected through a short exhaust pipe fitted with a valve as in the Fernez design . For the first time a man could breathe underwater with no connection to the surface at all – Le Prieur had invented the self - contained underwater breathing apparatus – scuba . Fernez ' s separate goggles didn ' t allow a dive deeper than ten metres because they were not pressurised , so as the diver went deeper the goggles were squeezed onto his face and eyeballs by the increasing water pressure , a phenomenon known as " mask squeeze " . In 1933 , Le Prieur replaced the Fernez goggles , noseclip and valve by a full face mask , directly supplied from the air cylinder , which balanced the pressure in the mask with the external water pressure . In 1934 Le Prieur was granted French patent 768083 for an improved hand - controlled self - contained underwater breathing apparatus with full face mask . The patent application was lodged in Paris on 2 February 1934 at 2 : 32 pm . The patent was awarded on 7 May 1934 and the patent specification was published on 31 July 1934 . The equipment delivered air at constant pressure without a demand regulator . Compressed air was contained in a cylinder carried on the diver ' s chest in a harness , delivering air to the full face mask at a pressure controlled by a hand operated regulator . Excess air , and the diver ' s exhaled breath , escaped by slightly lifting the edges of the mask . In 1946 , Le Prieur invented a further improvement to his scuba set . Its fullface mask ' s front plate was loose in its seating and acted as a very big , and therefore very sensitive , diaphragm for a demand regulator : see Diving regulator # Demand valve .