2. A period of scientific research, in which the flight of birds was studied and experiments made with lifting planes of various shapes. 3. A phase during which engineers built large, power-driven machines, but had not the skill to control them when in flight. 4. A stage in which, making a simple apparatus of wings, men glided from hilltops, and learned to balance themselves while in the air. 5. The stage in which, perfecting the gliding machines they had learned to control, men fitted petrol motors to them, and achieved at last a power-driven flight. In dim, remote ages, watching winged creatures as they skimmed above the earth, men longed passionately to fly; instead of scaling hills or creeping through woods, they desired to pass high above them; to spurn the obstructions of creatures earth-bound, and fly over mountains and seas. This longing to fly, even at the risk of life itself, was expressed beautifully by Otto Lilienthal, the greatest of the pioneers. He wrote: “With each advent of spring, when the air is alive with innumerable happy creatures; when the storks, on their arrival at their old northern resorts, fold up the imposing flying apparatus which carries them thousands of miles, lay back their heads and announce their arrival by joyfully rattling their beaks; when the swallows have made their entry and hurry through our streets and pass our windows in sailing flight; when the lark appears as a dot in the ether and manifests its joy of existence by its song; then a certain desire takes possession of man. He longs to soar upward and to glide free as a bird over smiling fields, leafy woods, and mirror-like lakes, and so enjoy the fairy landscape as only a bird can do.” But man’s first attempts to fly were ill-judged and foolish. He failed to understand the problems involved; he forgot that, even were he able to build a machine which would navigate the air, he must learn to control this craft; must learn to steer and balance it, and make it ride the gusts. One might, for example, take a bicycle and say to a man: “Here is a machine that can be propelled along the road; mount it and ride away.” But if the man had not learned to handle a bicycle, and balance himself on one, he would swerve for a few yards and then fall. So with the man who, without forethought or study, sought to navigate the air.