CONTENTS. ix 



PAGE 



The elastic ligaments more highly differentiated in wings which 



vibrate rapidly, . . . . . .193 



Power of the wing, to what owing, . . . .194 



Reasons w^hy the effective stroke should be delivered down- 

 wards and forwards, . . . . .195 



The wing acts as an elevator, propeller, and siistainer, both 



during extension and flexion, . . . .197 



Flight divisible into four kinds, . . . .197 



The flight of the Albatross compared to the movements of a 



compass set upon gimbals, . . . .199 



The regular and irregular in flight, . . . .201 



Mode of ascending, descending, turning, etc., . . .201 



The flight of birds referable to muscular exertion and weight, . 204 

 Lifting capacity of birds, • • • • • 205 



AERONAUTICS. 



The balloon, . . . • . . .210 



The inclined plane, , . . . . .211 



The aerial screw, . . , • , .215 



Artificial wings (Borelli's views), . . • .219 



Marey's views, ....... 226 



Chabrier's views, . . . . . . 233 



Straus-Durckheim's views, . . . . . 233 



The Author's views ; his method of constructing and applying 

 artificial wings, as contra-distinguished from that of Borelli, 

 Chabrier, Durckheim, and Marey, . . . 235 



The wave wing of the Author, . . . . 236 



How to construct an artificial wave wing on the insect type, . 240 

 How to construct a wave wing which shall evade the super- 

 imposed air during the up stroke, . . . .241 



Compound wave wing of the Author, .... 242 



How to apply artificial wings to the air, . . . 245 



As to the nature of the forces required for propelling artificial 



wings, 246 



