Flight under water, 90 Flight of the flying-fish, 98 Flight, horizontal, in part due to weight of flying mass, 110 Flight--the regular and irregular, 201 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 Fluids, resistance of, 18 Flying machine, Henson, 212 Do. Stringfellow, 213 Do. Cayley, 215 Do. Phillips, 216 Do. M. de la Landelle, 217 Do. Borelli, 219 A flying machine possible, 2, 3 Forces which propel the wings of insects, bats, and birds, 186, 189 Fulcra, yielding, 8, 104, 165 Gravity, the legs move by the force of, 18 Gravity, centre of, 18 History of the figure-of-8 theory of walking, swimming, and flying, 15 Joints, 23 Kite-like action of the wings, 98 Kite--how kite formed by wing differs from boy’s kite, 166 Laws of natural and artificial progression the same, 4, 17 Legs, moved by the force of gravity, 18 Lever--the wing one of the third order, 103 Levers, the three orders of, 19 Life linked to motion, 3 Lifting capacity of birds, 205 Ligaments, 24 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 Locomotion, the active organs of, 24 Locomotion, the passive organs of, 21 Locomotion of the horse, 39 Locomotion of the ostrich, 45 Locomotion of man, 51 Marey’s artificial wings, 233 Membranous wings, 170 Motion associated with the life and well-being of animals, 1 Motion not confined to the animal kingdom, 2 Motion, natural and artificial, 4 Motion, of uniform, 17 Motion uniformly varied, 17 Muscles, their properties, mode of action, etc., 24 Muscles arranged in longitudinal, transverse, and oblique spiral lines, 28 Muscles, oblique spiral, necessary for spiral bones and joints, 31 Muscles take precedence of bones in animal movements, 29 Muscular cycles, 26 Muscular waves, 26 Pendulums, the extremities of animals act as, in walking, 9, 18, 56, 57 Plane, inclined, as applied to the air, 211 Pettigrew’s method of constructing and applying artificial wings as contradistinguished from that of Borelli, Chabrier, Durckheim, Marey, etc., 235 Pettigrew’s _wave_ wing, 236 Pettigrew’s _compound wave_ wing, 242 Progression on the land, 37 Do. on or in the water, 64 Do. in or through the air, 103 Quadrupeds walk, fishes swim, and insects, bats, and birds fly, by figure-of-8 movements, 15, 16 Screws--the wing of the bird and the extremity of the biped and quadruped screws, structurally and functionally, 12 Screws--difference between those formed by the wings and those employed in navigation, 151 Sculling action of the wing, 231