PAGE 



Aerial creatures not stronger than terrestrial ones, • • ,13 

 Aerial flight as distinguished from sub-aquatic flight, • • ,92 

 Aeronautics, . ....... 209 



Air cells in insects and birds not necessary to flight, . . . 115 



Albatross, flight of, compared to compass set upon gimbals, . . 199 



Amphibia have larger travelling surfaces than land animals, but less 



than aerial ones, ....... 8 



Artificial fins, flippers, and wings, how constructed, . . .14 

 Artificial wings, Borelli, . . . , . . .219 



Do. Marey, 226 



Do. Chabrier, 233 



Do. Straus- Durckheim, ..... 233 



Do. how to apply to the air, .... 245 



Do. nature of forces required to propel, . . . 246 

 Artificial wave wing of Pettigrew, ..... 236 



Do. how to construct on insect type, . . . 240 



Do. how to construct to evade the supeiimposed air during 



the up stroke, ...... 241 



Do. can create currents and rise upon them, . . 253 



Do. can be driven at any speed ; can make new currents 



and utilize old ones, .... 251, 255 



Do. as a propeller and aerial screw, .... 256 



Do. compound rotation of : the difterent parts of the wing 



travel at different speeds, . . . . 252 



Do. necessity for supplying root of, with elastic structures, 247 

 Artificial compou7id wave wing of Pettigrew, .... 242 



Atmospheric pressure, effects of, on limbs, .... 24 



Axioms, fundamental, . . . . • • .17 



Balancing, how effected in flight, ..... 118 



Balloon, . . . . . . . . .210 



Bats and birds, lax condition of shoulder-joint in, . . . 190 

 Birds, lifting capacity of, ...... 205 



Body and wing reciprocate in flight, and each describes a waved track, 12 

 Bones, . . . . ... . .21 



Bones of the extremities twisted and spiral, ... 28, 29 



Bones of wing of bat — spiral configuration of their articular surfaces, . 176 

 Bones of wing of bird — their articular surfaces, movements, etc., . 178 

 Borelli's artificial bird, ....... 220 



Chabrier's artificial wings, ...... 233 



