Crittenden press. [volume] (Marion, Ky.) 1879-1907, 1902-11-06
SECRET OF BIRD SOARING.
A Naturalist who Thinks lie has Found
II Inside the Quilts.

IL INSIDE the Uullls.
What is the motive power Of a quiz
escent bird that moves it through air
resistance and keeps its heavy body
from falling? We are absolutely baf-
fled when confronted with the prob
lem of soaring bird. 1t does not
move its wings when it has once got
well started; its moving parts seem
to be of use merely to get it off to some
unknown dead center; it has infinite
capacity for taking advantage Of bal
ance, and all this is done while vio-
lating every known mechanical law,
holding up heavy body in the air,
and overcoming strong atmospheric
resistance at a rapid rate without dis
coverable expenditure Of energy.
Yet, says Chambers Journal,
weight is absolutely necessary for
flight, and the relative area of wing
expanse diIhinishes as the weight of
the bird increases. For example, a
gnat, which possesses very light,
fairy-like body, has about eleven
times the wing area of swallow in
proportion to the weight of each.
have been trying to discover the ex-
act structure of birds surfaces
which enables it to get the soaring
force from the air pressure under its
wings for the past fifteen years. The
task seemed hopeless until accident
settled the case. / had located in the
foothills Of the Flat Top mountains
of Colorado, in the dry air of that re-
gion, to prosecute my task, where the
yellow-tailed hawks, that were adj
mirable soaring birds, were abund-
ant.
A PERCEPTIONS cliff 1000 feet high
was near, from which | foated all
sorts Of surfaces, and year after year
the quest went on. A furious forest
fire had filled the air with smoke and
ashes and the odor of the burning
wood was in evidence for months. |
had killed a large hawk and was ex-
aiming its feathers, when stain was
detected on the sides of the quill be-
tween the spicules that was not be-
fore seen. A small magnifer gave il
the appearance of discolorations
about the throat of dust exhaust in
a planning mill.
n microscope was at once procured,
with an outfit Of detectives from G0to
100 diameters, and in an hours time
| knew more about bird flights than
% years Of study had given me. The
discolorations extended along each
spicule between the plates. The
downy flaments filling the double
wall structure Of the wings were
stained in the same unusual manner
This stain, when scraped off and ex.
amined, resembled SCOT from stove
pipe, showing that the air had been
going through the wing in an inces-
SAINT stream, carrying the smoke and
carbon particles of the fire with it, |
had been the slave of preconceived
ideas.
And this brings me to the device
that scars the bird. What is a
feather? 1t is an air engine, and the
bird surfaces are made of them.
They have been looked on as light,
flexible material for making an eX-
tended surface impervious TO air that
would readily fold upon itself, and
their exquisite mechanical structure
has been overlooked They consist of
a quill and two vanes made up of spi-
cules, between which are the plates.
The plates cross a channel about one
fortieth of an inch wide, made by the
spicules. There are about 1000 of
them to the inch, being practically in
Vulnerable, and they are located at
the outer surface, filling about one
fifth part Of the depth of the Channel.
They are about the twenty-thou-
sandth part of an inch thick, as
nearly as an amateur with a micro
scope could determine, so that nine
teen-twentieths of the space of the
channels is open to the passage of air.
The mechanical service of the
plates is obvious. The curve inn
pinges against the air current through
the feathers and drives the bird to the
front. Pressure produced by the
normal factor of weight is thus made
to serve as the motive power of flight.
Weapon Registers.