Evening star. [volume] (Washington, D.C.) 1854-1972, 1881-03-19
Flight. Natural and Artificial.

ALI, under ordinary conditions, is an eX-
tremely light, tenuous, and harmless fluid.
Still air is impalpabie to the touch, ard exerts
10 pressure save that known as atmospheric
pressure. Rouse 1t, however, as 1t rouses in
the tornado, and 1t becomes tremendous
power, equal to the upHoOttng Of trees, the 10
roofing OF houses, and the destruction OF navies
the mat er OF the air thus violently agitated
becomes In some senses Irresistible. It lifts
and Whlrls along solid masses Incredible In their
dimensions and weight. We have only to
transfer the fury OF the hurricane to the wings
or lying creatures to understand how they llfr
thelr bodies and hurl them through space. In
hight one or two things is necessary; either
the wings must be driven at a very high speed
In stfll cir; or the air, violently agitaJed must
strike the under surfaces OF the wings moving
gently, or held Ia enc position at an Upward
angle. after the manner OF boys kite. This
Is sane qua non. The speed at which wings
are driven dimlnishes In proportion as the
wings become large. but In every case they
must DE made to move more Or less briskly II
the air is not moving; and they must be made
TO move quicker than the air If the air Is TO be
any given direction. The great differences be-
tween the water ans the air as highways for
the locomoton OF animals amounts to this:
f anIa % %ao9r % De bgu heavy ncompressble
IN 1G, and affords comparatively substantial
recoil to its travelling surfaces. A swim.
ming animal ANNA has, eossequently, only to
light and highly compensate fluid. does not
float or buoy up the ANIMAL Immersed In it.
neither does it afford very substantial recoi
to Its travelling surfaces A lying animal
has, consequently, not only to propel
Itself, but also to float or buoy ITSELF The
analogy which obtains between the water and
the air as supporting medea has strangely and
gravely complicated the problem of fight; the
idea uppermost in most minds being, that a
lying creature must float upon the air as a ship
floats upon the water. This idea led to the dis.
coVery OF balloon by the Montgolfler broth
ers In 1872. nearly 100 years ago. AS, however,
everything which flies Is vestIy heavier than
the air, 1t follows that the balloon has no ana.
logue In nature. The balloon cannot In any
sense be regarded as a lying machine. In
calm Ii can only rtBe and fall IN vertical line
and II air currents are present tt Is waited
about, and Is completely at the mercy of the
WIND. AS It's horizontal movements cannot be
controlled 1t is useless as means Of transport
Is mere lifting apparatus. It resembles the
lying creature only In this, that it is immersed
In the ocean OF air In which it SuStains ITSELF
The mode OF suspension is wholly different
The balloon floats because 1t Is lighter than
the a1r-the lying creature Goats because ft
extracts from the air, by the vigorous down
ward action OF its WINGS certain amount OF
upward reco1l. The balloon IS passive; the fly.
Ing creature is active. The balloon is controlled
by the wind; the flying creature controls the
wind. The balloon IN the absence OF wind can
only rise and fall In q vertical line; the flying
creature can fly In a horiZOnte! plane In any
given direction. The balloon is inefficient be.
cause OF its levity; the lying creature is effi-
Client because OF its Weight.-FTd:jeT's Maya
zine.