Evening star., 1901-11-16
Mans Limitations in Sowing This
Old, New Problem.
NATURAL BLESSIHGSARE DRAWBACKS
For to Fly Wings as Well as Legs
and Arms Are Necessary.
RECENT ACCOMPLISHMENTS

Written for The Evening Star by Prof. Simon New
comb LID, FRS.
At first sight it may seem to detract from
mans boasted superiority that animals far
beneath him in intelligence can soar in
nidair, while he has to content himself
with making his slow and laborious way on
the ground. If nature did not give him
wings, why should not the genius which
has produced the telegraph and the tele-
phone succeed in making wings for him?
We may be sure he will not be satisfied till
he has solved this problem or found out
that no solution can be reached.
There are some considerations which may
lessen his dissatisfaction with what nature
has denied him. Inc bird is itself a flying
machine requiring nothing but brain to
direct 1t. Man cannot transform himself
into a mechanism for soaring above the
earth because for his upper limbs nature
has given him arms instead of wings. l
am sure he would not be willing to ex-
change these limbs for those of the bird,
especially as his legs would have to be
largely reduced In weight to enable him to
perform the aerial evoiutions of his brother
in feathers. What he really wants ~ to
have arms. legs and wings, all three, maxi
ing geological mOnstrosity which nature
would never produce if left to herself. Per-
haps. according to one theory of evolution
lists. If the desire Is maintained long enough
and with sufficient intensity, wings may bud
in the dim future, and million or so
generations from now man may flap his
wings, clap his hands, spring upon his
legs and soar into the ether. But at pres
ent we find that when he wishes to supply
himself with artificial wings he is averse
to amputating his legs and arms, conse-
quently the very blessings which nature has
showered upon him prove drawback when
he sets out to emulate the poor bird that
he is ready to shoot on sight. When he
oCly 70 IL oh md Rxy oil t,rnn OF
once, he demands more than nature is
ready to grant at this stage in the history
of the race, and the question is whether his
brains can do for him what nature as yet
denies.
What Man Can Do.
In an imperfect way they can. He Is
able to mount in balloon above the high
est flight of a bird. This Is something to
be proud of; but when he does it he cannot
progress with the speed of the bird, be-
cause his balloon must be so large as to
offer great resistance to the air. When M.
Santos-Dumont recently flew round the
Eiffel tower he achieved a success which
may lead us to hope for something yet bet
ter. But to improve on this we must have
more powerful machinery, and this if car
ried much farther will require greater
weight and larger balloon to keep it
a1oat. So as we gain in one direction we
lose in another. 1t is hopeless to look fer
a balloon that can be propelled with the
speed Of a railway train. If man would
fly with the speed Of a bird he must supply
himself with wings of some sort.
What he can do with wings Is limited by
inexorable and well-established physical
laws. By a profound investigation of the
laws of aerial flight Langley was enabled
to construct a machine which rose into the
air and flew half a mile over the Potomac
river But he did not allow any one to
ride on the machine: so the latter had to be
left to take direction which soon after
the start became Its own.
The physical laws to which I have re-
ferred show that there Is nothing inner
entity impossible in aerial flight. as there
is, for instance, in such a problem as
squaring the circle. Upon one Of these
laws all hope of solving the problem must
be based; it is therefore of sufficient i'm
portance to be explained.
We know that If man in falling through
the air hangs by a parachute his fall will
be slower the larger the spread of the sup
porting surface. We also have learned
that a spread of a few square yards will
suffice to make the fall so slow that one
may drop with impunity from balloon at
any height. The law to which l allude is
this: If the parachute is a fiat surface, and
If it is forced edgewise through the air at
the same time that 1t is falling, then the
more rapidly 1t moves edgewise the slower
will be its descent. By giving sufficiently
rapid motion the fall may be made as slow
as we desire This is the great secret of
the soaring bird, which must change soar
ing to fly as soon as it's speed slackens.
Seat man on horizontal fiat surface,
like a stiff sail or a thin rigid plane, and
start him flying forward with speed of
few hundred feet per second, and his fall
will be slow, indeed.
The Soaring Birds Secret.
Upon this principle is based the idea of
flight. But difficulty arises at the out
set If the journey is to be long one. How
ever slow the fall, the man must of neces-
cit To ho at
To evade this result the aeroplane, as it is
called, must be inclined to the horizon and
propelled forward in direction the oppo-
site of it's inclination-that is to say, the
higher edge must be the forward one. 1t
was for this reason that Langley attached
a propeller to his aeroplane, with the re-
suit l have mentioned.
Langley also claims and I think he is
right, that if we leave out of consideration
the friction of the surface against the air
and consider only the pressure upon 1t then
the faster the aeroplane flies the less the
power required to keep 1t supported. Ii,
however, it Is to carry anything with it
and 1t must carry It's driving engine and its
load-then the power required to overcome
the resistance of the air will increase as
the cube of the speed, as In the case of
steamship driven through the water.
may here explain that while the resistance
in pounds varies only as the square Of the
speed, yet the engine power Is measured
by the product of the speed into the re-
S1Stance ana this produces the cube. IhuS
to double the speed Of a steamer we must
multiply the horse power of her engines
by eight and increase her daily consump-
tion of coal in the same proportion. In the
meantime, since she completes her voyage
in half the time, the total consumption for
the trip will! only be multiplied by four
1t follows from this that the speed we can
secure has a practical limit, imposed by
the very nature Of the case. But we have
some compensation In the fact that the
horizontal motion which Is to sustain us
in the air need not be that Of the whole
machine, but may equally well be that OF
the wings Of a horizontal windmill. &c,
the wings at the proper angle, then apply
a power sufficient to make them turn fast
enough and up we go. Give a very slight
inclination to the axis Of rotation of the
wings and we shall soar forward. Alto
gether. from an ideal standpoint, the fly
ing machine seems quite within our reach.
But before we can reach out and grasp 1t
we must go through complicated course
Of calculation based upon strength and
weight Of materials, power of engines, heat
of combustion and laws of aerial resistance.
Until we make this calculation we are like
the child to whom the task Of putting
ladder up to the moon seemed so simple
that he cried to have 1t done.
Expert Knowledge.