AERONAUTICS. 



253 



remrsing the wing, and in preparing it for the stroke from 

 left to right, and vice versa ; a continuous to-and-fro move- 

 ment devoid of dead points being thus established. If the 

 artificial wave wing be taken in the hand and suddenly de- 

 pressed in a more or less vertical direction^ it immediately 

 springs up again, and carries the hand with it. It, in fact, 

 describes a curve whose convexity is directed downwards, and 

 in doing so, carries the hand upwards and forwards. If a 

 second down stroke be added, a second curve is formed ; the 

 curves running into each other, and producing a progressive 

 waved track similar to what is represen ted at a, c, e, g, i, of 

 fig. 81, p. 157. This result is favoured if the operator runs 

 forward so as not to impede or limit the action of the wing. 



How the Wave Wing creates currents, and rises upon them, 

 and how the Air assists in elevating the Wing. — In order to 

 ascertain in what way the air contributes to the elevation 

 of the wing, I made a series of experiments with natural 



Fig. 129. 



and artificial wings. These experiments led me to conclude 

 that when the wing descends, as in the bat and bird, it 

 compresses and pushes before it, in a downward and forward 



