The Kimball graphic. (Kimball, Brule County, Dakota [S.D.]) 1883-1905, 1886-10-15
THE NAVIGATION OF THE AIR.
Ono Mode OF Travel that Battles uu-
man Ingenuity-Ihe Flight
of Birds.

Ono Mode of Travel that Baf1lcs Iu-
man Ingenuity-The Flight
of Birds.
Man, with his thirst for knowledge,
his increasing desire to pry into natures
laws, and wonderful inventive genius,
has been able to accomplish wonders.
says The Pittsburgh Dispatch.
We can not go to the planets to view
them, SO by our telescopes we bring the
nlanets to us. With microscopes we
Hyserve the daily life of the most minute
organisms. The telegraph and tele-
phone enable us to converse with friends
who are miles away. Our application
OF the power of steam takes us to dis
tant places in days time which in
former years would have required
months. but there is yet remaining one
mode of travel which seems to battle
human ingenuity. That is the naviga-
tion of the air-a problem which will
never be solved until some moving
power be discovered which is very much
lighter than any we now know, and
machinery employed which is in ac-
cordance with the natural laws which
enable birds to fly with such ease.
| 1t is perfectly useless to attempt to
| navigate the ;lir by means OF balloons.
a balloon rises because lis lighter than
air and floats upon or in it; but for
! this reason it is wholly at the mercy OF
| the air curreut; one might as well cx-
| pect to control the motions of II thistle
blow. There is general idea that
| birds sustain themselves in the air
largely on account of lightness, and
on account of their hollow bones being
| filled with heated air, but it is quite
manifest that if they were rs light or
| lighter than the air they could not
make any forward motion, rs like the
thistle blow they would be carried
hiIher and thither by every breath of air.
| One of the most potent factors in
| birds flight, therefore, is its weight.
The force OF gravitation works con-
stant influence upon the bird TO draw it
toward the earth, and the force of the
stroke of its wings must be enough,
and little more than enough to over
come this force of gravity. In so do
ing the weight of the body acts rs
fulcrum, or in other words, gives it
something to push against, and help it.
when it has gained momentum. to sail
along without any effort, except that eX-
pended in keeping the wings stretched
The amount of force used in tlyinr
is very great, much more than is sup
posed. The constant beating of the air
necessary to keep the body from falling
to the ground is not all, The bird must
also be propelled forward. The muscu-
lar force expended by humming birds
and other birds whose wings move
rapidly must be enormous. Anyone
who has watched a heron knows that
they move their wings slowly, and yet
they will find, to their surprise, that if
the wing-beats are counted they amount
to l2O to $50 strokes minute. \ hum
mer's wings move so fast that they can
not be seen, only blur at each side of
its body is noticeable, and the number
of beats per minute is inconceivable
representing wonderful expenditure
of force and energy
The duke OF Argyll, in very enter
tanning chapter entitled 'Contrvance Il
Necessity" speaks of q birds wings
and the mechanism of flight in these
words: mo more beautiful example
can be found, even in the wide domain
of animal mechanics. none of which
we can trace more clearly, too. the
mode and method in which laws, the
most vigorous and exact, are used as
the supple instruments of purpose.
The construction of the wing and
the b rd's delicate and expert use of it
are very interesting subject, and have
formed the basis of all attempts of
man to construct device for navira-
ting the air.
| There are things about wing which
would be very hard to initiate in any
piece of machinery. In the first place,
the wing must be of sufficient surface
and supplied with sufficient Muscular
forces so that its strokes upon the air
will be able to counteract the force of
gravity drawing the bods to the earth.
but it would seem that the upward
stroke would neutralizc this completely,
just us if in rowing q boat, the oar
should be kept in the water as it recov-
cred for q fresh stroke. The wing,
| however, is SO eontrived that the mini
mum OF resistance is encountered. The
feathers Of the wing underlie each 9TH
er SO that during the downward beat
these feathers are forced to lie togeth-
er, thereby preventing the air from
passing through, SIS the vane of one
feather lies against the shaft of the
next, but during the upper beat these
are all opened like so many valves. al
lowing free passage of the air and not
obStructing the wing.
Bes DIES this the general shape of the
wing facilitates the motion. All wings
are concave below and rounding above
During the downward blow the air is
collected and offers resistance, and dur
ing the reverse the air flows off the up
per side, very well illustrated by any
one who is in a strong wind with an
umbrella. The wind will roll off the
upper side easy enough, but turn and
hold the cOncave side to the blast
and it is nearly pulled out of the hand.
This then will account for the ability
of the bird to keep rising, but does not
explain the forward motion. A wing,
feathers fastened to the skin or bone in
the front of the wing. and at liberty be-
hind. AS the bird strikes, the air can
not escape through the wing, nor in
front, as 1t meets there with the firm re,
sistance of the bone, so the only place
it has is at the back of the wing, turn
ing the feathers up little there and
giving n forward impluse to the body
! very much as the wind does which is
blowing in a quartering direction upon
the sail Of a boat, or better still upon
kite. The kite must be held in posi-
ton by a string, and the weight OF the
birds body takes the place of the
string. Then the wings beng moved
at the proper anglo the bird is able to
ascend, descend or move forward.
The phenomenon of soaring is done
by the same mechanism. That is. BY 9
delicate holding of the wings at the pre-.
else angle necessary to keep the body
moving.