The Owosso times. (Owosso, Mich.) 18??-1882, 1881-11-11
How Birds Fly.

You will find, If you carefully ex-
anime birds wing, that all the bones
and muscles are placed along the front
edge, which is thus made very stiff and
strong. The quill feathers are fastened
in such way that they point back
ward, so that the hind edge of the
wing is not stiff like the front edge,
but is flexible aud bends at the least
touch. AS the air is not 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 is
stiff and strong, it retains its hollow
shape, and prevents the air from slid
ing out in this direction, but the pres
sure 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 it escape there, and slides
out backward. The weight of the
bird is all the time pulling it down
toward the earth; so at the sameltime it
slides out upward and backward past
the bent edge of the wing, the wing
itself, and with it the bird, slides for
ward and downward off from the con-
fined air. 1t is really its weight which
causes it to do this, so that the state
ment 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, so
that the flying is nothing but sliding
down a hill made of air. A bird rises
by tapping its wings, and it flies by
falling back toward the earth and slid
ing forward at the same time. At the
end of each stroke of its wing it has
raised itself enough to make up for the
distance it has lost since the last stroke,
and accordingly it stays at the same
height and moves forward in a straight
line.
If you watch the flight of those birds
which flap their wings slowly, such as
the wood-P seeker, you can see them rise
and, fall, and will have no trouble in
seeing that their path. is not really a
straight line, but is made up of curves;
although most birds flap their wings so
rapidly that they have no time to fall
through 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 a kite, so that the
wind shall slide out under them, they
can sail great distances without flap
ping their wings at all. They are sup
ported, as a 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 driv.
ing 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 60 in whatever direc
tion they wish, much as a boy changes
his direction in skating by leaning a
little to one side or the other. Some
birds are very skillful at this kind OF
sailing, and can even remain station
ary for some minutes when there is a
strong wind; and they do this without
tapping their wings at all. 1t is u diff
ficult thing to do, and no birds but the
most skillful flyers can manage it
Some hawks can do it, and gulls an(
terms may often be seen practicing il
when gale of wind is blowing, ant
they seem to take great delight in theil
power of flight.