AERIAL NAVIGATION. 391 



and was broken. Its short flight disclosed that its stability was im- 

 perfect and Sir Hiram Maxim has not yet undertaken the construction 

 of the improved machine which he is understood to have had under 

 contemplation. 



Having already built in 1872 and 1891 two full-sized flying ma- 

 chines with doubtful results, Mr. Ader, a French electrical inventor, 

 built in 1897 a third machine at a cost of about $100,000 furnished by 

 the French War Department. It was like a great bird, with 270 feet 

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

 screws actuated by a steam engine of 40 horse power which weighed 

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

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

 fective that further advance of funds was refused. The amount lifted 

 per horse power was 27 pounds. 



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

 tested October 7 and December 8, 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 worthless. 

 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 successfully tested on the seven- 

 teenth of December. For three years they experimented with gliding 

 machines, as will be described farther 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 yet 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, applying 

 thereto a new and effective mode of control of their own. They 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 anybody. 



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 



