Introduction
In the 15th century, Leonardo da Vinci, whose genius shone in both art and science, drew designs of various types of "heavierthan-air flight machines," some of which closely resemble those in use today. Medical investigations in aeronautics were initiated soon after the Montgolfier brothers invented the balloon in 1783. A sheep, a duck, and a rooster were sent up in a balloon at Versailles, and were found to be none the worse for their experience. In October, 1783, the first actual flight was made by man. Pilâtre de Rozier and the Marquis d'Arlandes ascended to 3000 ft. in a huge, smoke-filled balloon. In December of the same year, Charles was raised aloft to 10,500 ft. and complained of severe pain in his right ear and jaw, the first recorded physical discomfort associated with flight. Two years later, Dr. John Jeffreys, of Boston, flew with the Frenchman Blanchard from Dover