Green-Mountain freeman. [volume] (Montpelier, Vt.) 1844-1884, 1878-09-18
Che family Cirele.

How BIRDS FLY.-You will find. if you
carefully examine 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
backward. so that the hind edge of the
wing is not stiff like the front edge, but is
flexible and bends ut he least touch. AS
The air is not solid, but IL gas. it has ten
dency to slide out from under the wing
when this is driven downward, and, of
course. it will do this ut the point where it
can escape most easily. Since the front
edge of the wing is stiff and strong, it re
tains 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
1T 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 backward past the
bent edge of the wing, the wing itself, and
with it the bird. slides forward and down
ward off from the confined air 1t is
fcblly IT'S Wcl&uu WuiCll CtuotS IL W wv tu'o'
so that the statement that bird flies by
by its own weight is strictly true. This is
true, also, of insects and bits. They all
have wings with stiff front edges. and
flexible hind edges which bpnd anil allow
the air to pass out, so that flying is moth
ing but sliding down hill ma lie of air
A bird rises by tapping its wings and il
tlies by failing back toward the earth ami
sliding forward al the same time. AT the
end of each stroke of its wings it has rails
ed itself enough to make up for the dts
lance it has fallen since the last stroke,
md accordingly it Stays at the same height
and moves forward in seemingly straight
line But if YOU watch the fight of those
birds which fltp their wings slowly, such
rs the woodpecker, you can see them rise
md fall, and will have NO trouble in see
ing that their path is not really Il straight
line, but is made up of curves; although
most birds flap their wings 80 rapidly tina
they have no time to fall through space
great enough to he seen Birds also m Ike
use of the wind to aid them in flight. an
by holding their wings inclined like a
kite, so that the wind shall slide out under
them, they can sail great Ills ances without
lltppllp b'lCll Wings w tli' AhCJ dtC ouP-
ported, rs Il paper kite is, by, the wind,
which is continually pushing against their
wings, and sliding out backward and
downward, thus liftng or holding up the
bird, and at the same time driving it for
ward. The birds are not compelled 10
face the wind while they are sailing. but
by changing the position of tho wings
little they can 90 in whatever direction
they wish, much as Il boy changes his d.
rection in skating by leaning little to
one side or the other. Some birds are
very s>illful ut this kind of sailing, and
can even remain stationary in the air for
some minutes when there is IA strong wind;
and they do this without tapping their
wings ut all. 1t is Il difficult thing to do.
and no birds except the most skillful fl, ers
can manage it. Some hawks can do it,
and gulls and terms may often be seen
practicing it "hen gale OF wind is blow
ing, and they seem TO take great delight in
their power Of tiight.-St. Nicholas.