SCIENCE AND INVENTION 237 



The whole apparatus steel frame, miniature steam 

 engine, smoke stack, condensed-air chamber, gaso- 

 line tank, wooden propellers, wings weighed about 

 twenty-four pounds. There was developed a steam 

 pressure of about 115 pounds, and the actual power 

 was nearly one horse-power. At a given signal the 

 aeroplane was released from the overhead launching 

 apparatus on the upper deck of the house-boat. It 

 rose steadily to an ultimate height of from seventy 

 to a hundred feet. It circled (owing to the guys of 

 one wing being loose) to the right, completing two 

 circles and beginning a third as it advanced ; so that 

 the whole course had the form of a spiral. At the 

 end of one minute and twenty seconds the propellers 

 began to slow down owing to the exhaustion of fuel. 

 The aeroplane descended slowly and gracefully, ap- 

 pearing to settle on the water. It seemed to Alex- 

 ander Graham Bell that no one could witness this 

 interesting spectacle, of a flying machine in perfect 

 equilibrium, without being convinced that the possi- 

 bility of aerial flight by mechanical means had been 

 demonstrated. On the very day of the test he wrote 

 to the Academic des Sciences that there had never 

 before been constructed, so far as he knew, a heavier- 

 than-air flying machine, or aerodrome, which could 

 by its own power maintain itself in the air for more 

 than a few seconds. 



Langley felt that he had now completed the work 

 in this field which properly belonged to him as a 

 scientist " the demonstration of the practicability 

 of mechanical flight " and that the public might 

 look to others for its development and commercial 

 exploitation. Like Franklin and Davy he declined 



