The first man to approach flying on a scientific basis was Roger Bacon, an Englishman who lived during the 13th century. He envisioned the air about us as a sea, and he believed that a balloon could float on the air just as a boat did on water. His balloon, or air boat, was to be filled with ethereal air so that it might float on the air sea. We do not know what Bacon meant by ethereal air; yet, many still credit him with the basic concept of balloon flight. Almost four hundred years later, Francesco de Lana, an Italian priest, applied Bacon's principie of air flight. He designed a boat, complete with mast and sail, which would be held in the air by four hollow spheres. Each of the four balls was to be 20 feet in diameter and made of very thin copper. The air was to be removed from the balls so that they could float in the sky and lift the boat into the air.
De Lana's boat was never built since it was not possible to make spheres of such thin metal and such size in those days. Even if they had been built, the thin spheres would have been crushed by the pressure of the atmosphere.
