From the theoretical point of view, Professor Langley, an American, reached in his _Experiments in Aerodynamics_ the important conclusion that weight could best be countered by speed. From theory Langley turned to practice and in 1896 designed a steam-driven machine which flew three-quarters of a mile without an operator. Seven years later, at the end of 1903, he produced a new machine fitted with a 52 horse-power engine weighing less than 5 lb. per horse-power; but this machine was severely damaged ten days before Wilbur Wright made his first flight in a controlled power-driven aeroplane. THE WRIGHT BROTHERS AND THEIR SUCCESSORS IN EUROPE. The Wright brothers directed their whole attention to aviation in 1899. By 1902, as the result of many experiments, they had invented a glider with a horizontal vane in front, a vertical vane behind, and a device for "warping" the wings. Their longest glide was 622-1/4 feet. This was followed by the construction of a machine weighing 600 lb., including the operator and an 8 horse-power engine, which on December 17th, 1903, realized the dreams of centuries. After an increasing number of experiments, a machine built in 1905 flew 24-1/4 miles at a speed of 38 miles an hour. It is interesting to recall that the new invention was refused once by the United States and three times by the British Government. It was not until September 13th, 1906, that Ellehammer, a Danish engineer, made the first free flight in Europe, his machine flying 42 metres at a height of a metre and a half. About the same time reports of the Wrights' successes began to reach Europe and were quickly appreciated by the French. Space forbids that I should enter into the achievements of the early French aviators, among whom the names of Ferber, Bleriot and Farman will always rank high in the story of human faith, courage and determination. It is a record of rapid advance. Farman made a circuit flight of 1 kilometre in 1908, and flew from Chalons to Rheims, a distance of 27 kilometres, in twenty minutes. Bleriot crossed the Channel in a monoplane of his own design in forty minutes. French designers improved the control system, and French machines became famous. The records of the Rheims meeting of 1909 serve to illustrate the progress made during the first phase of aviation. Latham won the altitude prize by flying to a height of over 500 feet. Farman the prize for the flight of longest duration by remaining more than three hours in the air, and the passenger carrying prize by carrying two passengers round a 10-kilometre course in 10-1/2 minutes. The Gnome rotary engine was first used with success at this meeting. Before turning to the pioneer efforts in England and the pre-war organization of our air forces, some account of the development of the lighter-than-air dirigible is desirable. THE FIRST AIRSHIPS.