to have a peculiar function assigned to it; neither is it necessary to reproduce the intricacy of that machinery by which the pinion in the bat, insect, and bird is moved: all that is required is to distinguish the properties, form, extent, and manner of application of the several flying surfaces, a task attempted, however imperfectly executed, in the foregoing pages. When Vivian and Trevithick devised the locomotive, and Symington and Bell the steamboat, they did not seek to reproduce a quadruped or a fish; they simply aimed at producing motion adapted to the land and water, in accordance with natural laws, and in the presence of living models. Their success is to be measured by an involved labyrinth of railway which extends to every part of the civilized world; and by navies whose vessels are despatched without trepidation to navigate the most boisterous seas at the most inclement seasons. The aëronaut has a similar but more difficult task to perform. In attempting to produce a flying-machine he is not necessarily attempting an impossible thing. The countless swarms of flying creatures testify as to the practicability of such an undertaking, and nature supplies him at once with models and materials. If artificial flight were not attainable, the insects, bats, and birds would furnish the only examples of animals whose movements could not be reproduced. History, analogy, observation, and experiment are all opposed to this view. The success of the locomotive and steamboat is an earnest of the success of the flying machine. If the difficulties to be surmounted in its construction are manifold, the triumph and the reward will be correspondingly great. It is impossible to over-estimate the boon which would accrue to mankind from such a creation. Of the many mechanical problems before the world at present, perhaps there is none greater than that of aërial navigation. Past failures are not to be regarded as the harbingers of future defeats, for it is only within the last few years that the subject of artificial flight has been taken up in a true scientific spirit. Within a comparatively brief period an enormous mass of valuable data has been collected. As societies for the advancement of aëronautics have been established in Britain, America, France, and other countries, there is reason to believe that our knowledge of this most difficult department of science will go on increasing until the knotty problem is finally solved. If this day should ever come, it will not be too much to affirm, that it will inaugurate a new era in the history of mankind; and that great as the destiny of our race has been hitherto, it will be quite out-lustred by the grandeur and magnitude of coming events. INDEX. AERIAL creatures not stronger than terrestrial ones, Air cells in insects and birds not necessary to flight, Albatross, flight of, compared to compass set upon gimbals, Amphibia have larger travelling surfaces than land animals, but less than aërial ones, Artificial fins, flippers, and wings, how constructed, Artificial wings, Borelli, PAGE 13 92 209 115 199 8 14 219 Do. Marey, 226 can be driven at any speed; can make new currents compound rotation of: the different parts of the wing Artificial compound wave wing of Pettigrew, Atmospheric pressure, effects of, on limbs, Axioms, fundamental, 252 necessity for supplying root of, with elastic structures, 247 Body and wing reciprocate in flight, and each describes a waved track, 12 21 Bones of the extremities twisted and spiral, 28, 29 Bones of wing of bat-spiral configuration of their articular surfaces, 176 178 220 CHABRIER'S artificial wings, 233 ELYTRA or wing cases and membranous wings, FEATHERS, primary, secondary, and tertiary, Fins, flippers, and wings form mobile helices or screws, Flight the poetry of motion, Flight the least fatiguing kind of motion, Flight under water, Flight of the flying-fish, Flight, horizontal, in part due to weight of flying mass, Flight-the regular and irregular, Flight-how to ascend, descend, and turn, Flight of birds referrible to muscular exertion and weight, Fluids, mechanical effects of, on animals immersed in them, Flying machine, Henson, Do. Do. Do. Do. Do. Stringfellow, PAGE 170 180 14 3, 4, 110, 111, 112, 113 90 98 110 201 201 204 18 18 212 213 215 216 217 219 2,3 186, 189 A flying machine possible, Forces which propel the wings of insects, bats, and birds, Fulcra, yielding, GRAVITY, the legs move by the force of, Gravity, centre of, 8, 104, 165 HISTORY of the figure-of-8 theory of walking, swimming, and flying, JOINTS, KITE-LIKE action of the wings, Kite-how kite formed by wing differs from boy's kite, LAWS of natural and artificial progression the same, Legs, moved by the force of gravity, 3 Lifting capacity of birds, 205 Ligaments, 24 Ligaments, elastic, position and action of, in wing of pheasant, snipe, Ligaments, elastic, more highly differentiated in wings which vibrate Motion associated with the life and well-being of animals, Motion not confined to the animal kingdom, Motion, natural and artificial, Motion, of uniform, Motion uniformly varied, . Muscles, their properties, mode of action, etc., Muscles arranged in longitudinal, transverse, and oblique spiral lines, Muscles, oblique spiral, necessary for spiral bones and joints, Muscular cycles, Muscular waves, PAGE 17 17 24 28 31 29 26 9, 18, 56, 57 211 235 236 242 37 64 103 PENDULUMS, the extremities of animals act as, in walking, Pettigrew's method of constructing and applying artificial wings as QUADRUPEDS walk, fishes swim, and insects, bats, and birds fly, by SCREWS the wing of the bird and the extremity of the biped and Screws—difference between those formed by the wings and those em- Speed of wing movements partly accounted for, Spine, spiral movements of, transferred to the extremities, 12 151 231 188 120 33 233 66 74 78 89 Swimming of the turtle, triton, crocodile, etc., TERRESTRIAL animals have smaller travelling surfaces than amphibia, The travelling surfaces of animals variously modified and adapted to WALKING, Swimming, and flying correlated, Wave wing of Pettigrew, how to construct to evade the superimposed air during the |