vii FLIGHT 273 



that the propelling force must act by means of wings. 

 Quite recently Herr Lilienthal has tried to navigate 

 the air with an equipment resembling a bird's. But 

 though his wings have enabled him, starting from 

 an elevation, to sail over 800 yards before sinking to 

 earth — a truly wonderful feat of pluck and skill — 

 it is improbable that any one could ever succeed 

 by the help of such appliances in rising and main- 

 taining himself in the air ; and nothing short of this 

 can be called flight. Mr. Maxim has advanced a great 

 deal further. He has seen that we ought not, in 

 trying to rival a bird, to imitate it slavishly, as the 

 first sewing-machine is said to have imitated the 

 hand-sewn stitch, and he has, therefore, employed 

 screws for the propulsion of his flying-machine. In 

 animal mechanism, where the different parts cannot 

 be separated, screws are, of course, out of the question. 

 In man-made machinery a screw is better than a lever. 

 It has no idle intervals, whereas a wing during the 

 upstroke would be no better than a parachute. 

 Besides this, it is doubtful whether machinery would 

 not be too clumsy to effect all the turns that a wing 

 must make even in straight-ahead flight. As soon as 

 Mr. Maxim's machine was allowed to run along its 

 line of rails at a rate of thirty-six miles per hour, it 

 rose in the air, and but for contrivances designed to 

 restrain it from mounting more than a very little, there 

 is no knowing what heights it might have reached. 

 This great aeroplane, weighing 8,000 lbs., imitates a 

 sea-bird rising from the water : it presents to the air 

 a surface inclined slightly upward, and this inclined 

 surface causes it to rise when it travels fast. But 



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