264 



INDEX. 



PAGE 



Wave wing, compound, . . . . . . •. 242 



Weight necessary to flight, ...... 110 



Weight contributes to flight, . . . . . . 112 



Wei2;ht, momentum, and power to a certain extent synonymous in 



flight, . ■ . . . . . . . .114 



The Y^ng of the bird and the extremity of the biped and quadruped are 



screws, structurally and functionally, ... 12, 136 



Wing in flight describes flgure-of-8 curves, . . . .12 



Wing during its action reverses its planes and describes a figure-of-8 

 , track in space, . . . ; . . .140 



Wing when advancing with the body describes looped and waved tracks, 143 

 Wing, margins of, thrown into opposite curves during extension and 



flexion, ........ 146 



Wing, tip of, describes an ellipse, ..... 147 



Wing and body reciprocate in flight, and each describes a wave track, 12 

 Wing moves in opposite curves to body, . . . .168 



Wing ascends when body descends, and vice versd, . . . 159 



Wing during its vibrations produces a cross pulsation, . . . 148 



Wing vibrates unequally with reference to a given line, . 150, 231 



Wing, compound rotation of, . . . . . .149 



Wing a lever of the third order, ...... 103 



Wing acts on yielding fulcra, . . . . - 8, 104, 165 



Wings, their form, etc. , all wings screws, structurally and functionally, 136 

 Wing capable of change of form in all its parts, . . . 147 



Wing-area variable and in excess, ..... 124 



Wing-area decreases as the size and weight of the volant animal in- 

 creases, ........ 132 



Wing, natural, when elevated and depressed must move forwards, . 156 

 Wiug, angles formed by, when in action, . . . . 167 



Wing acts as true kite both during down and up strokes, . . 165 



Wing, traces of design in, ...... 180 



Wing of bird not always opened up to same extent in up stroke, . 182 

 Wing, flexion of, necessary to flight of birds, . . . .183 



Wing flexed and partly elevated by action of elastic ligaments, . 191 



Wing, power of, to what owing, . ..... 194 



Wing, effective stroke of, why delivered downwards and forwards, . 195 

 Wing acts as an elevator, propeller, and sustainer both during exten- 

 sion and flexion, ....... 197 



Wings, points wherein the screws formed by, differ from those in ordi- 

 nary use, . . . . " . . . . 151 



Wings at all times thoroughly under control, . . . . 154 



Wings of insects, consideration of forces which propel, . . . 186 



Wings of bats and birds, consideration of forces which propel, . . 189 



