Aerial creatures not stronger than terrestrial ones, 13
Aërial flight as distinguished from sub-aquatic flight, 92
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 aërial ones, 8
Artificial fins, flippers, and wings, how constructed, 14
Do. nature of forces required to propel, 246
Do. how to construct to evade the superimposed 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. compound rotation of: the different parts of the wing travel at different speeds, 252
Do. necessity for supplying root of, with elastic structures, 247
Artificial _compound wave_ wing of Pettigrew, 242
Atmospheric pressure, effects of, on limbs, 24
Bats and birds, lax condition of shoulder-joint in, 190
Body and wing reciprocate in flight, and each describes a waved track, 12
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
Elytra or wing cases and membranous wings, 170
Feathers, primary, secondary, and tertiary, 180
Fins, flippers, and wings form mobile helices or screws, 14
Flight, weight necessary to, 3, 4, 110, 111, 112, 113
Flight the least fatiguing kind of motion, 13
Flight, horizontal, in part due to weight of flying mass, 110
Flight--how to ascend, descend, and turn, 201
Flight of birds referrible to muscular exertion and weight, 204
Fluids, mechanical effects of, on animals immersed in them, 18
Forces which propel the wings of insects, bats, and birds, 186, 189
Gravity, the legs move by the force of, 18
History of the figure-of-8 theory of walking, swimming, and flying, 15
Kite--how kite formed by wing differs from boy’s kite, 166
Laws of natural and artificial progression the same, 4, 17
Lever--the wing one of the third order, 103
Ligaments, elastic, position and action of, in wing of pheasant, snipe, crested crane, swan, etc., 191
Ligaments, elastic, more highly differentiated in wings which vibrate quickly, 193