AERIAL NAVIGATION. 179 



French war department. It was like a great bird, with 270 feet sup- 

 porting surface and 1,100 pounds weight, being driven by a pair of 

 screws actuated by a steam engine of 10 horsepower, which weighed 

 about 7 pounds per horsepower. Upon being tested under the super- 

 vision of the French army officers, the equilibrium was found so 

 defective that further advance of funds was refused. The amount 

 lifted per horsepower was 27 pounds. 



The data for the full-sized flying machine of Professor Langley, 

 tested October 7 and December S, 1903, have not yet been published. 

 From newspaper photographs it appears to be an amplification of the 

 models which flew successfully^ in 1896, and this, necessarily, would 

 make it very frail. The failures, however, seem to have been caused 

 by the launching gear and do not prove that this machine is useless. 

 Like the failures of Maxim and of Ader, it does indicate that a better 

 design must be sought for, and that the first requisites are that the 

 machine shall be stable in the air, shall be quite under the control of 

 its operator, and that he, paradoxical as it may appear, shall have 

 acquired thorough experience in managing it before he attempts to fly 

 with it. 



This was the kind of practical efficiency acquired by the Wright 

 brothers, whose flying machine was successful!}^ tested on the 17th 

 of December. For three years they experimented with gliding 

 machines, as will be described further on, and it was only after they 

 had obtained thorough command of their movements in the air that 

 they ventured to add a motor. How they accomplished this must be 

 reserved for them to explain, as they are not 3^et ready to make known 

 the construction of their machine nor its mode of operation. Too 

 much praise can not be awarded to these gentlemen. Being accom- 

 plished mechanics, they designed and built the apparatus, appl3nng 

 thereto a new and effective mode of control of their own. The}^ 

 learned its use at considerable personal risk of accident. They planned 

 and built the motor, having found none in the market deemed suitable. 

 They evolved a novel and superior form of propeller; and all this was 

 done with their own hands, without financial help from anybod3\ 



Meantime it is interesting to trace the evolution which has led to 

 this result and the successive steps which have been taken by others. 



It is not enough to design and build an adequate flying machine; 

 one must know how to use it. There is a bit of tuition which most of 

 us have seen — that of the parent birds teaching their 3'Oung to fl3' — 

 which demonstrates this proposition. Even with thousands of years' 

 evolution and heredity, with adequate fl3ing organs, the birdlings need 

 instruction and experience. 



Safety is the all-important requisite. It is indispensable to have a 

 flying machine which shall be stable in the air and to learn to master 

 its management. Nothing but practice, practice, practice will gain 



