The Hickman courier. [volume] (Hickman, Ky.) 1859-current, 1878-09-13
How Birds FlY.
Cst. Nicholas fer September.

You will find, if you carefully ex-
anime a birds wing, that all the boues
and muscles are placed on the front edge,
which is thus made very stiff and strong.
The quill feathers are fastened in such
a way that they point backward 50 that
the hind edge of the wing is 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 a tendency to
slide out from under the wing when this
is driven downward, and, of course, it
viii do this at point where it can es-
cape most easily. Since the front edge
of the wing is stiff and strong, it retains
it, 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 feath-
ers 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 il
down toward the earth; so, at the same
time that the air slides out upward and
backward past the bent edge of the
wing, the wing itself, and with it the
bird, slides forward and downward of
from the confined air. It is really its
own weight which causes 1t to do this, so
that the statement that a 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 flying is nothing but sliding down
hill made of air. A 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
Itself enough to make up for the distance
it has fallen since the last stroke, and
accordingly it stays at the same height
and moves forward in a seemingly
straight line. But if you watch the
flight of those birds which flap their
wings slowly, such as the wOOdpecker,
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 nc
time to fall through a space great enough
to he seen. Birds also make use of the
wind to aid them in flight, and by hold
ing their wings inclined like kite, SO
that the wind shall slide out under them
they can sail great distances without
tapping their wings at all. They are
supported, as a paper kite is, by the
wind, which is continually pushing
against their wings, and sliding out
backward and downward, thus lifting OF
holding up the bird, and as 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 lit
tie they can go in whatever direction
they wish, much as a boy changes his di
rection in skating by leaning little t
one side or the other. Some birds ART
very skillful at this kind of sailing, anC
can even remain stationary in the all
for some minutes when there is a strong
wind and they do this without Tapping
their wings at all. 1t is a difficult thing
to do, and no birds except the mos
skillful flyers can manage it. Som,
hawks can do it, and gulls and tern
may often be seen practicing it when ;
gale of wind is blowing, and they seen
to take great delight in their power O
flight