THE TRIUMPH OF THE AEROPLANE 



These experiments, which destroyed the calcula- 

 tions of Newton, long held to be correct, showed that 

 mechanical flight was at least theoretically possible, 

 indicating as it did that a weight of two hundred pounds 

 could be moved through the air at express-train speed 

 with the expenditure of only one horse-power of energy. 

 Since engines could be constructed weighing less than 

 twenty pounds to the horse-power, theoretically such 

 an engine should support ten times its own weight in 

 horizontal flight in an absolute calm. As a matter of 

 fact there is no such thing as an absolute calm in 

 nature, air-currents being constantly stirring even on 

 the cahnest day, and this introduces another element in 

 attaining aerial flight that is an all-important one. 

 Indeed it has long been recognized that the mechanical 

 power for flight is not the only requisite for flying — 

 there is, besides, the art of handling that power. 



EXPERIMENTS IN SOARING 



Those who have watched soaring birds sail for 

 hours on rigidly extended wings will remember that 

 while there is no flying movement, there are certain 

 shifts of the rigid body, either to offset some unex- 

 pected gust of wind, or to produce movement in a 

 desired direction. There is an art of balancing here 

 that has become instinctive in the bird by long practice 

 which could not be hoped for in the same degree in a 

 mechanical device, and which man could hope to ac- 

 quire only by practice. But in the nature of the case 

 man has little chance to learn this art of balancing in 



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