CONTENTS. 



447 



The figure of 8 in rapid horizontal flight is opened out so that the "Wing describes a looped 



and then a waved track, ...... 328, 340 



Method of testing the Accuracy of the figure of 8 theory of Wing movements, 

 Mode of Investigation pursued by the Author, .... 



The Wing capable of change of form in all its parts, 



The Wing mobile and flexible as well as elastic — mobility and flexibility necessary to flight 



The margins of the Wing thrown into opposite curves during extension and flexion, 



The Wing inclined forwards at the end of the down stroke, and backwards at the end of the 



up stroke, .... 



The rotation of the posterior margin of the Wing in a downward direction increases the 



elevating, but decreases the propelling, power, .... 

 The Wing attacks the air at various angles, ..... 

 The Wing during its vibration produces a cross pulsation, 

 Analogy between the Wing in motion and the sounding of sonorous bodies, 

 The Wing during its vibrations moves on the surface of an imaginary sphere, 

 The tip of the Wing describes an ellipse, ..... 

 The Wing vibrates unequally on either side of a given line, . 

 The natural Wing, when elevated and depressed, must move forwards, 

 The Wing acts as a kite both during the down and up strokes, 

 Where the kite formed by the Wing differs from the Boy's kite, 

 Points wherein the Wing differs from the scull of the Boatman, 

 A regulating power necessary in Flight, 

 The Wing at all times thoroughly under control, 

 Rapidity of Wing movements partly accounted for, 

 How balancing is effected in flight, . 

 The Body and Wing move in opposite curves, 

 The Body ascends when the Wing descends, and vice versa, 

 Weight contributes to horizontal flight, 

 Weight necessary to flying Animals as at present constructed ; Weight and Levity relatively 



considered with regard to aeriel and subaquatic Flight (Diving 

 The Wing elevated indirectly by the operation of gravity, . 

 The Wing acts upon yielding fulcra, 



Consideration of the forces which propel the Wing of the Insect, 

 Analysis of the down and up strokes of the Wing of the Insect, 

 The direction of the stroke of the Wing of the Insect, what effective, what non-effective 



the kite-like action of the Wing, ...... 



Mechanical theory of the action of the Insect's Wing as stated by Chabrier, 

 Objections thereto, ....... 



Analysis of the movements of the Wing of the Wasp — reversal of the planes of the Wing — 



reciprocating action, &c, 

 The down and up strokes of the Wing of the Butterfly ; Increase and diminution of the Wing 



area; development of figure of 8 curves on the margins of the Wing, . 

 Analysis of the down and up strokes of the Wing of the Bird and Bat, 

 The Wing of the Bird descends as a long lever (p. 368), and ascends as a short lever, 

 The importance to be attached to the concavo-convex form of Wing in Birds, 

 The under or concave surface of the Wing of the Bird effective both during the down and up 



strokes, ......... 



The Wing of the Bird forms a natural parachute from which the body depends both durin 



the down and up strokes, ....... 



The Wing of the Bird cranked slightly forward ; compound rotation of the Quill Feathers, 

 The primary, secondary, and tertiary Feathers are geared to each other, and act in concert, 

 They overlap or imbricate, ........ 



The up or return stroke of the Wing of the Bird ; valvular action of Wing, 



The Wing not always opened up to the same extent in the up stroke, 



Lax condition of the Shoulder Joint in Birds (p. 370) ; how the Wing is attached to the body 



movements of the Shoulder, Elbow, Wrist, and other Joints, . 

 VOL. XXVI. PART II. . 5 Z 



341, 342 

 334 

 332 

 329 

 365 

 328 



335 



368 

 337, 383 

 330 

 330 

 343 

 330 

 374 

 344 

 345 

 346 

 339, 340 

 390 

 391 

 399 

 397 

 347 

 343, 352 

 355 



371 

 370 

 355 

 363 

 347 



337 



357 



358, 364 



338 



359 

 366 

 373 

 369 



369 



371 

 375 

 376 

 380 

 377 

 381 



393 



