Baden-Powell joined the army at 22; within a year he was lecturing on military uses of lighter-than-air flight. He was one of several notables expressing interest in the Aeronautical Navigation Conference at the
1893 World's Fair. In 1894, Baden-Powell made the first British military balloon flight. Baden-Powell wrote an article including "''What will the good citizens of London say when they see a hostile dynamite-carrying aerostat hovering over St. Paul's?''" He wrote to
Lord Kelvin, who replied that he had "not a molecule of faith" in flight. Baden-Powell became a Fellow of the
Royal Geographical Society (elected in 1891) and a Fellow and, in 1900, President of the
Royal Aeronautical Society. He also wrote, "Ballooning as a Sport", published in 1907 by William Blackwood and Sons. With his sister
Agnes, they built and flew in their own hot-air balloons, man-carrying kites, gliders and powered aircraft. He invented a twelve-foot man-carrying kite that he flew at Whitton Park, Hounslow, England, and later a three-kite system that he called the
Levitor. He helped
Marconi in Newfoundland in his efforts to transmit and receive radio messages across the Atlantic, using Baden-Powell's man-carrying kite to lift the radio aerial. Baden-Powell also developed a collapsible
military bicycle. He obtained one of the first British patents for a television system, "An electrical method of reproducing distant scenes visually", published 19 April 1921 (GB161706). And he contributed to the
Encyclopædia Britannica entry on 'kite-flying'. ==Patents==