Many men did not see why we should not to some extent imitate the flight of our successful rivals, the birds. It is true that from the earliest times many men have tried to make wings that could fly, but these attempts always ended in failure or disaster. The human body is too heavy in proportion to the power of the muscles. Birds are much stronger in proportion to their weight than we are. Their bones are built on a lighter plan, and there is no probability that we should be able to alter the construction of our own bones for the purposes of flight. Nor is that necessary. There are many ways of keeping a body afloat in air. Some birds can keep afloat for a long time without flapping their wings at all, and most people are acquainted with the trick of making a card fly through the air by giving it a rapid turning motion. It was an American, Professor Langley, who first constructed a small machine which could fly through the air by means of its own mechanism. He found that the faster a flat surface is moved through the air in a horizontal direction, the less power it requires to keep it up. He concluded that if a machine is provided with horizontal wings, and driven very fast through the air, it will not require a very powerful engine to keep it up once a fairly high speed is attained. He launched his apparatus over a lake, and had the pleasure of seeing it fly for miles before it fell into the water. When this principle had been established other inventors straightway proceeded to apply it. Two American motor manufacturers of the name of Orville and Wilbur Wright constructed a machine capable of carrying a man. Two years ago the first public trial of a flying machine was successfully made in Paris, when Mr. Santos Dumont, a young Brazilian balloonist, flew several hundred yards in a machine heavier than air. This machine consisted of a number of boxes open at both ends and covered with tightly-stretched canvas. [Illustration: Fig. 77.--Blériot’s Aeroplane leaving France.]