The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1878-08-30
How Birds Fly.

You will find, if You carefully examine
birds wing, that all the bones and
muscles are placed along the front edge,
The quill feathers are fastened in such O
way that they point backward, so that
the hind edge of the wingis not stiff like
the front edge, but is flexible and bends
at the least touch. AS the air is not a
solid, but a gas, it has tendency to
slide out from under the wing when this
is driven downward, and of course it will
do this at the point where it can escape
most easily. Since the front edge OF
the wing is stiff and strong, il retains its
hollow shape, and prevents the air from
sliding out in this direction, but the
pressure of the air is enough to bend up
the thin, flexible ends of the feathers at
the hinder border of the wing, so the air
makes its escape there, and slides out
backward and upward. The weight of
the bird is all the time pulling it down
toward the earth; so, at the same time
that the air slides out upward and back
ward past the bent edge of the wing, the
wing itself, and with it the bird, slides
forward and downward off from the con-
fined air. 1t is really its weight which
causes it to do this, so that the statement
that bird flies by its own weight is
strictly true.
This is true, also, of insects and bats.
They all have wings with stiff front
edges, and flexible hind edges which
bend and allow the air to pass out, 80
that flying is nothing but sliding down a
hill made of air. bird rises by flap
ping its wings, and it flies by falling
back toward the earth and sliding for
ward at the same time. AT the end of
each stroke OF its wings it has raised it
self enough to make up for the distance
IL has fallen since the last stroke, and
accordingly it stays at the same height
and moves forward in seemingly
straight line. But if you watch the
fight of those birds which flap their
wings slowly, such as the woodpecker,
yon can see them rise and fall, and will
have no trouble in seeing that their path
is not really straight line, but is made
up of curves; although most birds flap
their wings so rapidly that they have no
time to fall through a space great
enough to be seen. Birds also make use
of the wind to aid them in flight, and by
holding their wings inclined like kite,
so that the wind shall slide out under
them, they can sail great distances with.
out Tapping their wings at all. They
are supported, as paper kite is, by the
wind, which is continually pushing
against their wings, and sliding out
backward and downward, thus lifting or
holding up the bird, and at the same
time driving it forward.
The birds are not compelled to face
the wind while they are sailing, but, by
changing the position of the wings a
little, they can go in whatever direction
they wish, much as a boy changes his
direction in skating by leaning little
to one side or the other. Some birds
are very skillful at this kind of sailing,
and can even remain stationary in the
air for some minutes when there is
strong wind and they do this without
Tapping their wings at all. 1t is diff
ficuit thing to do, and no birds except
the most skillful flyers can manage 1t.
Some hawks can do it, and gulls and
terms may often be seen practicing it