it will be evident that a remarkable analogy exists between walking,
swimming, and flying. It will further appear that the movements of
the tail of the fish, and of the wing of the insect, bat, and bird
can be readily imitated and reproduced. These facts ought to inspire
the pioneer in aërial navigation with confidence. The land and water
have already been successfully subjugated. The realms of the air alone
are unvanquished. These, however, are so vast and so important as a
highway for the nations, that science and civilisation equally demand
their occupation. The history of artificial progression indorses
the belief that the fields etherean will one day be traversed by a
machine designed by human ingenuity, and constructed by human skill.
In order to construct a successful flying machine, it is not necessary
to reproduce the filmy wing of the insect, the silken pinion of the
bat, or the complicated and highly differentiated wing of the bird,
where every feather may be said 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.
[Illustration]
INDEX.
PAGE
Aerial creatures not stronger than terrestrial ones, 13
Aërial flight as distinguished from sub-aquatic flight, 92
Aëronautics, 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 aërial 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 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. as a propeller and aërial screw, 256
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
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
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 poetry of motion, 6
Flight the least fatiguing kind of motion, 13
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
Speed attained by insects, 188
Speed of wing movements partly accounted for, 120
Spine, spiral movements of, transferred to the extremities, 33
Straus-Durckheim’s artificial wings, 233
Swimming of the fish, whale, porpoise, etc., 66
Swimming of the seal, sea-bear, and walrus, 74
Swimming of man, 78
Swimming of the turtle, triton, crocodile, etc., 89
Terrestrial animals have smaller travelling surfaces than amphibia,
amphibia than fishes, and fishes than insects, bats, and birds, 8
The travelling surfaces of animals increase as the density of the
media traversed decreases, 7, 8
The travelling surfaces of animals variously modified and adapted
to the media on or in which they move, 34
Walking, swimming, and flying correlated, 5
Walking of the quadruped, biped, etc., 9, 10, 11
_Wave_ wing of Pettigrew, 236
Do. how to construct on insect type, 240
Do. how to construct to evade the superimposed air during the up
stroke, 241
Do. can be driven at any speed, 251, 255
Do. can create currents and rise upon them, 253
Do. can make new currents and utilize existing ones, 251, 255
Do. as a propeller, 256
Do. as an aërial screw, 256
Do. forces required to apply to the air, 245, 246
Do. necessity for supplying root of, with elastic structures, 247
Wave wing, _compound_, 242
Weight necessary to flight, 110
Weight contributes to flight, 112
Weight, momentum, and power to a certain extent synonymous in
flight, 114
Wing of the bird and the extremity of the biped and quadruped are
screws, structurally and functionally, 12, 136
Wing in flight describes figure-of-8 curves, 12
Wing during its action reverses its planes and describes a
figure-of-8 track in space, 140
Wing when advancing with the body describes looped and waved
tracks, 143
Wing, margins of, thrown into opposite curves during extension and
flexion, 146
Wing, tip of, describes an ellipse, 147
Wing and body reciprocate in flight, and each describes a wave
track, 12
Wing moves in opposite curves to body, 168
Wing ascends when body descends, and _vice versâ_, 159
Wing during its vibrations produces a cross pulsation, 148
Wing vibrates unequally with reference to a given line, 150, 231
Wing, compound rotation of, 149
Wing a lever of the third order, 103
Wing acts on yielding fulcra, 8, 104, 165
Wings, their form, etc., all wings screws, structurally and
functionally, 136
Wing capable of change of form in all its parts, 147
Wing-area variable and in excess, 124
Wing-area decreases as the size and weight of the volant animal
increases, 132
Wing, natural, when elevated and depressed must move forwards, 156
Wing, angles formed by, when in action, 167
Wing acts as true kite both during down and up strokes, 165
Wing, traces of design in, 180
Wing of bird not always opened up to same extent in up stroke, 182
Wing, flexion of, necessary to flight of birds, 183
Wing flexed and partly elevated by action of elastic ligaments, 191
Wing, power of, to what owing, 194
Wing, effective stroke of, why delivered downwards and forwards, 195
Wing acts as an elevator, propeller, and sustainer both during
extension and flexion, 197
Wings, points wherein the screws formed by, differ from those in
ordinary use, 151
Wings at all times thoroughly under control, 154
Wings of insects, consideration of forces which propel, 186
Wings of bats and birds, consideration of forces which propel, 189
[Illustration]
PRINTED BY T. AND A. CONSTABLE, PRINTERS TO HER MAJESTY, AT THE
EDINBURGH UNIVERSITY PRESS.