Page:Popular Science Monthly Volume 79.djvu/413

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the development of mechanical flight the United States has taken an honorable place both in theory and in practise. The work of Langley, Chanute and the Wright brothers can not be paralleled by any other nation. While in many directions we have done more than our share in mechanical invention, it has often happened that we have depended on Great Britain, France and Germany for scientific principles. But Langley was an eminent physicist and Chanute a leading engineer. It is interesting to know how far their achievements in aeronautics were based on mathematics and physical research and how far on empirical trials. The Langley "Memoir on Mechanical Flight," just published by the Smithsonian Institution, gives full details in regard to the work done by Langley and under his direction. The first part of the volume was in the main written by him in 1897; the second part, dealing with further experiments with the small models and with the large aerodrome, has been written by Mr. Charles M. Manly, who became assistant in charge of the experiments in 1898.

In 1891 Langley announced as the result of experiments carried on through previous years that machines could be constructed which would give such a velocity to inclined surfaces that bodies indefinitely heavier than the air could be sustained upon it and moved through it at a great speed. As a result of experiment and theory it was proved that one-horse power