Marshall County Republican. (Plymouth, Ind.) 1856-1878, 1878-08-29
Birds I'm The Air, and the Air In Birds.

The chief peoullariaty Of birds is
their power Of flight. and, although
there are few birds which do not fly,
most OF them do, and the various or
gans OF their bodies are all construc-
ted in such way as to fit them for a
life in the air. Their bodies are very
solid and compact. in order that
most of their weight shall be near the
place where the wings are attached.
The feet, legs. head, and neck are
light, and so arranged that they may
be drawn up close to the body while
the bird is flying. AS the neck is
long and very flexible, the body does
not need to be plant, as with most
creatures having backbones; bnt it is
important that the wings should have
a firm support, so the bones OF the
back are united. The body OF bird
must also be well protected from the
cold; for, as it ascends and descends
through the air, it passes through re-
gions Of very different temperatures,
and it must be provided with a thick
and warm covering in order to be
able tc endure there sudden changes,
and one also which shall be very
light and able to shed the water: for.
otherwise, bird would pe unable to
fly. The feathers Of a bird answer to
all these needs, and are so placed up
on the body that they form a smooth
surface which does not catch against
the air when the bird is passing
Thought. In Its rapid ascents and
descents, the bird is exposed to an
other danger even greater than the
sudden changes Of temperature. You
all know that air presses in every d.
rection with great force, and that we
do not feel it because there is air in
all parts OF our bodies as we'll as out
side them, and the pressure OF the air
inside exactly balances that OF the
outside air. II we should suddenly
take away the outside air in any way,
such as covering person up with an
air pump receiver, and quickly and
completely exhausting the air, the
consequence OF the inside pressure
would be very terrible, aud il the ex-
pertinent could be tried quickly
enough the body would burst like an
exploding gun, with a loud noise.
When people 60 up rapidly in
balloon OF climb very high mountains,
they are troubled by ringing noise
and feeling Of great pressure in the
ears and head, and by palpitation of
the heart, bleeding at the nose, and
fainting. These unpleasant and often
dangerous symptoms are caused by
the expansion OF the air inside their
bodies. In ascending very high
mountains IL is necessary to go very
slowly and to stop very often, to give
time for some of the expanded air to
escape, and equalize the pressure
again. Now, many birds. the condor.
for example. fly over the tops of the
highest mountains, and nearly all
birds, either occasionally or habitual-
ly, ascend to very great attitudes, and,
unless there were some plan for reg
ulating the pressure OF the air inside
their bodies, they would suffer great
inconvenience and even pain and dan
ger. But they are provided with an
arrangement by which the air within
them can escape easily as it expands
and thus keep the pressure within
just equal TO that outside, so that
they can ascend and descend as rap
idly as they wish. without feeling the
least Inconvenience. In the body Of
the bird there are several large bags,
like the lungs, called air chambers;
many OF their bones are hollow, and
others are pierced with long winding
tubes called air-tubes. All these air.
chambers and ATTITUDES are con-
nected with the lungs so that air can
pass into and out OF them at each
breath. The connection between
these chambers and the lungs Is so
complete that a wounded hawk can
breathe through a broken wing almost
as well as through his mouth. When
bird mounts upward, the air inside
its body gradually expands, but the
bird does not feel any Inconvenience
for, at each breath, part OF the air
passes from the air chambers into the
lungs, so that the pressure on the in
side does not become greater than
that on the outside st. Nicholas for
September.