The morning news. [volume] (Savannah, Ga.) 1887-1900, 1891-06-26

of the feathers in the rear OF the
wing, thus communicating a. push for
ward TO the body of the bird. BY this
mechanical eontriyance the same volume of
air is made to do the double duty Of sustain
ing the birds weight and OF communicating
to it forward impulse. The creature,
therefore, has only TO repeat its perpendicu-
lar blows upon the atmosphere in order to
sustain and propel itself. II you take in
your hand the stretched wing Of heron
which has been dried in that position ard
strike it quickly downward you will find it
very difficult to maintain the vertical direc-
ton OF the stroke, and that II You do not
use much force to resist the tendency your
hand will be carried forward.
WEIGHT AND NOT BUoYANcY.
SIN all the beautiful evolutions of birds
upon the wing 10 is weight and not buoy
ancy which makes these eyolutions possible.
True, one often sees birds soaring with no
motion of their wings that 10 perceptible,
but this they are enabled to do by using as
a sustaining force the breeze that strikes
against the widespread vanes extended from
their bodies. 10 is the principle Of the kite.
To bring thesetwo forces-the wind and
Rravity-iuto the perfect balance necessary
for accomplishing this feat called soaring
requires the most expert and accomplished
powers of flying. such as few
birds possess To perform it, the animal
must expand or contract its pinions exactly
TO the right size and hold them precisely at
the correct angle. The slightest alteration
in these adjustments produces instantly an
upsetting Of the balance. Fowls which seek
their food In the air have long aud powerful
wings and their command of them is 80 per-
feet that they can pick up a flying gnat in
the air while travelling at the rate of fifty
miles an hour. Such In particular ARE the
powers at some species of the swallow tribe.
"In some birds the wing has to be adapted
to the double purpose of flight and diving.
In their case large area Of pinien has to
be dispensed with, because ii could not be
worked to advantage dnder water. Thus
you find that all diving birds have very
small wings and in some OF them the wing
is nothing more than powerful fin for use
10 swimming and Of no utility whatever for
fight. ar sSizsas fi1y ben
TAILS NOT USED AS RUDDEHg.gt
at is popularity imagined that tNe Birds
tails serve them as rudders for steering pur.
poses, but thatiis not true. If they had
been designed bynature with that object in
view they would have been set with their
vanes vertical and not horizontal The APP
pendage, In fact, is merely intended for a
balance, and you will find that all birds
which possess great ease in evolution
through the air have largely de-
veloped tails Humming birds are
perhaps the most remarkable ex-
amples known to the machinery of flying
Their power Of posing themselves In the air
while searching the blossoms for insects, re-
naming absolutely stationery, is extraor-
binary, depending not upon soaring but
upon the inconoeivably rapid motion Of
their wings. as you may observe for yeur-
self any summer day.
1.-THE smaller birds wings IN proportion
TO the weight Of the body the more rapidly
it must flap them in order TO sustain Itself.
The huge spread OF the owl, with its soft
and feathery plumage, enables it to float
through the night air so noiselessly in pur-
suit of prey that you might not hear
it IL 1t passed close by your head On
the other hand, the smaller wings of the
diving birds must be agitated with great
rapidity to sustain them, and they have so
little power Of floating in the atmosphere
that they come into contact with the water,
when after fish, with flop and a shower
bath. All the same it Is the small winged
birds. like the duck and the pigeon, that fly
the fastest. Their maximum speed has been
estimated at 100 miles an hour, but am iu-
clined to think that an exaggeration. Cali
10 half that and IL is fast.n