The San Francisco call. [volume] (San Francisco [Calif.]) 1895-1913, 1895-05-12

are crossing the bay and notice how they
do this You will see that the first Joint
of the wing to where it bends backward
and forward is strong and compact cup
shaped underneath. The second joint ia
pers The feathers are long and less COM
pact than they are on the first division of
the wing. where they overlap thickly. To-
ward the ends the wing coverts spread
little and turn little upward. The upper
surface of the wing is convex, the under
surface concave. The wings are thrown
forward and downward notice that par
ticularly. Flying is not a tapping OF the
wings up and down. The bird throws his
wings forward and downward. The air is
forced back, compressed In the little cup
shaped hollow of the wings, which, by the
recoil thus obtained, drag the body of the
creature forward.
Thus the bird climbs on the air, grasp
ing the air in its wings, as it were, and
pulling its body after it.
1t used to be supposed that the air sac
of birds, and the compressed, heated air
which is found in the hollows in the bones
of some species, were necessary to flight,
but the bats and some of our best flyers
among birds have no air sacs and some of
our most famous birds OF passage have no
air in their bones.
Structurally speaking, the wing of a bird
is screw-that is, it twists in opposite di-
rections during the up and the down
strokes. The wing of a gull in flying de-
scribes figure of in the air. The wings
are always in advance of the body in
hying. If a bird were to strike its wings
backward and downward, as so many artists
delight to picture it as doing in flight, the
creature would turn a forward somersault
in the air.
The birds always fly against the wind.
During calm on the bay you will hardly
see the gulls flying at all. Or if they do
essay flight, you will be struck at once by
the laborious aspect of the process. There
being no wind upon which to climb the
bird must by the rapid action of his wings
snlite the air with sufficient vigor to estab-
lish q recoil that will send him along. You
can get an illustration of this in watching
the flight of different water birds. The
little mudhen flies close to the surface of the
water, ready to dive the instant danger
threatens. It's wings yibrate swiftly, I'M
ceasingly, for it rarely rises high enough
above the water to be able to take advan-
tage of the air currents. The gulls, on the
contrary, rise from the water, iutter their
wings rapidly for an instant, and, gaining
an impetus, rise to where they soar against
the wind, using their wings as parachute.
pinions, they circle ands turn and travel
through the air at will, lowering over the
steamers and giving free lessons in air
transit to all who study the art.
1t is not my purpose here to go into the
mechanics of flight, even of birdfight, but
merely to give hint or two by which the
travelling methods of birds may be OBJ
served. II we ever have a successful air.
ship it will be modelled not upon the prin-
ciple of the balloon but of the bird.
To fly! Tho very thought sets the nerves
a-tingle. There is Joy in being afoat,
with wet sheet, a flowing sea and
wind that follows fast" There is Joy in
being on the back of a swiftly running
horse, to feel the air rushing away from
brain; but to traverse the air as the birds
do-this Joy we long for; we have right
to long for.
To what heights may we rise? This is
the question that concerns US most after
all. Sordid, creeping wights that we are,
we still
To man propose this test
Thy body at its best,
How far that project thy soul on its lone way?
Our very protests, our kicking against
the pricks that would incite us to higher
efforts are but our blind fear lest after all
they may not mean fight. We are afraid
of our own instincts, ashamed of our own
aspiring impulses, the upward impulse
that has throbbed through all life since the
world began.
Usually we are content to groyel. We
walk over our little round and declare it
to be our destiny. We pirate learnedly of
the limitations of poor human nature. We
declare ourselves worms of the dust and
the spirits of light who look upon US might
readily believe our assertion.
But there are moments when the scales
are lifted from our eyes. We know that
we have higher destiny. We know that
we have barred the way against our own
progress. We know that our trend is up
ward; that we are born for flight, and we
know that we know all this.
Still afar in the sky the hawk scars seek
ing his prey Still, here with my feet
upon the earth, / follow him in my flight,
seeking that which is above and beyond.
The Lost Has Been Found.