The Durham daily globe. (Durham, N.C.) 1889-1894, 1894-01-20

$o"c 70 SoAVluR the fToDlehs
Man will yet learn how to fly. Pro.
lessor Langley, secretary Of the Smith.
sonian institution, SO declared in an ad.
dress delivered before the National
Academy of Sciences This ought to
give much encouragement to thinkers
who hope that mankind will some day
secure domain in the element of birds,
just as it has already done, thanks to the
evolution of submarine boats and diving
gear, in that Of fishes. The distinguish
ed scientist referred to expressed conf
dence that the c~ontrivance Of the future
for aerial navigation would be on the
kite principle.
The air possesses elements Of buoy
ancy which have not been recognized
hitherto. There is no truth in the popu-
lar conception that a body heavier than
the atmosphere cannot be suspended in
that medium without motion. A kite
of sticks and paper is much heavier than
the fluid which it displaces, but it is sus-
tanned aloft. You can find an example
much more striking, however, in the
eagle or the frigate bird, which, though
an animal of considerable weight, re-
mains poised in the sky upon extended
pinions motionless for hours together, so
that a telescope may be trained on it.
Thousands Of feet above the earth it is
sustained without movement of a feath-
er, though in a rarefed atmosphere.
This is possible because the suspended
fowl has an instructive knowledge Of the
way In which to utilize the air currents
for its support. When man has learned
how this can be done he will be able to
fly. The most advanced investigators in
this subject reject the balloon and all
other such lifting devices as impracti-
cable; a gas lighter than air can never
be safely confined within a receptacle
that is not weighty, and the same objec-
ton applies to a vacuum
Ballooning today is about where it
was when it was first invented, and in
the nature of things it never get much
further. Aluminium is light for a metal,
but it is several times too heavy to be
successfully utilized for such purposes
Pray, what has become of those alumni
mum trains of cars that were to be run
through the air from Chicago to New
York at sixty minutes the trip?
LESSONS FROM BIRDS.
There is a school Of flying machine in
ventors who may be designated as the
"fappers," inasmuch as their idea is to
sustain their contrivances by the flap
ping of birdlike wings. But they doubt
less forget that the best flyers among
birds do not support themselves by flap |
ping. On the contrary, they only resort
to that performance when it is necessary |
for a start.
The eagle, if launching himself from
level ground, is obliged to take quite a
run first; then, Tapping his wings with
. violent muscular effort which he coult
not keep up for long, he gains a sum.
Gent altitude to render it possible for |
him to strike along the plane of an air
which holds him up.
Floating with librating pinions from
one air current to another, he is lifted, |
with an occasional broad sweep of his
powerful wings, to the upper aerial re-
where he simply floats, opposing
to each movement of the suspended
ether the gentle force necessary to main
tain him in his stationary position.
These principles which the eagle ap-
plies for purposes Of flight are perfectly
understood in the theory Of mechanics.
1t is only necessary to adapt them with
suitable apparatus in order to give to
human beings like powers. True, the
bird is lighter in proportion to it's size
than is man; it's bones are hollow and
illed with warm air from the lungs.
But the difference in this respect is
aot very material, and it may easily be
compensated for by bigger wings. Pow
er to flap them is not what is required,
nasmuch as the start can be made from
height; what is wanted is the knowl-
which inherited experimenting
given the fowl as to how to
the angles Of the wings to the air
A PRACTICABLE
This is precisely what Professor Lang
ely has been experimenting with. What
le is attempting is to produce a machine
to flotation upon the air cur
ents like a kite. You can find a very
imple illustration of the principle he is
working on in the trick done with play
ng cards by the prestidigitator Herr
mann, who throws them from the stage
nto the highest gallery of the biggest
heater in tba IIpita5 C+o%ao d;e+r;b-+;3-