236 



AEEONAUTICS. 



great expenditure of power and a disastrous waste of time. 

 The wing, to be effective as an elevating and propelling 

 organ, should have no dead points, and should be character- 

 ized by a rapid winnowing or fanning motion. It should 

 reverse and reciprocate with the utmost steadiness and 

 smoothness — in fact, the motions should appear as continuous 

 as those of a fly-wheel in rapid motion : they are so in the 

 insect (figs. 64, 65, and 66, p. 139). 



To obviate the difficulty in question, it is necessary, in my 

 opinion, to employ a tapering elastic rod or series of rods 

 bound together for the anterior margin of the wing. 



If a longitudinal section of bamboo cane, ten feet in length, 

 and one inch in breadth (fig. 117), be taken by the ex- 

 tremity and made to vibrate, it will be found that a wavy 

 serpentine motion is produced, the waves being greatest 

 when the vibration is slowest (fig. 118), and least when it 

 is most rapid (fig. 119). It will further be found that at 

 the extremity of the cane where the impulse is communi- 

 cated there is a steady reciprocating movement devoid of dead 

 2mnfs. The continuous movement in question is no doubt 

 due to the fact that the different portions of the cane 

 reverse at different periods — the undulations induced being 

 to an interrupted or vibratory movement very much what 

 the continuous play of a fly-wheel is to a rotatory motion. 



The Wave Wing of the Author. — If a similar cane has added 

 to it, tapering rods of whalebone, which radiate in an out- 

 ward direction to the extent of a foot or so, and the whale- 

 bones be covered by a thin sheet of india-rubber, an artificial 

 wing, resembling the natural one in all its essential points, 

 is at once produced (fig. 120). I propose to designate this 

 wing, from the peculiarities of its movements, the wave 

 wing (fig. 121). If the wing referred to (fig. 121) be made 

 to vibrate at its root, a series of longitudinal {c d e) and 

 transverse {fgh) waves are at once produced; the one series 

 running in the direction of the length of the wing, the other in 

 the direction of its breadth (vide p. 148). This wing further 

 tivists and untwists, figure-of-8 fashion, during the up and down 

 strokes, as shown at fig. 122, p. 239 (compare with figs. 82 

 and 83, p. 158; fig. 86, p. 161; and fig. 103, p. 186). 



