The Sun.
London, England, 1863-09-10 00:00:00

HOW TO FLY !

A NEW SCHEME OF AERIAL NAVIGATION.—An article
in the September number of Weldon's Register, after set-
ting forth some new and curious arguments and calcu-
lations with a view to disprove the doctrine taught by the
Times, that " the problem of mrial navigation will be readily
solved [by means of artificial wings) whenever the pro-
gress of science shall place us in command of a motive
power sufficiently lighter, in proportion to its capabilities,
than the steam engine," and to show that, even if we had
" an engine which, while capable of putting forth any re-
quired amount of force, should weigh absolutely nothing at
all, the transport of passengers or merchandise by means of
artificial wings would still be as impossible as it is at pre-
sent," proceeds as follows :
And yet man may navigate the air if he will, and as soon
as he will. To the question—" If by means neither of
balloons nor of artificial wings, than by what means r I
reply—By imitating, not the birds, but the fishes.
The birds and the fishes constitute the only examples
we have in nature of animals being able to sustain them-
selves in, and at the same time to propel themselves
through, an element lighter than the heavier portions of
their own bodies. We have seen by what means the birds
do this, and that we cannot imitate them. In the case of
the fishes, the matter is managed in another way. Unlike
the bird in flying, the fish in swimming has no weight to
bear, and so all the exertion it needs to put forth is for
the purpose of propelling itself. The greater portion of
its flesh and bones is of as nearly as possible the same
specific gravity as the element which it inhabits, and the
excess of weight of the heavier portions is balanced by
means of a long narrow bag filled with some gaseous body
by many more times lighter than water than hydrogen is
lighter than atmospheric air. As a whole, the body of the
fish is thus rendered of exactly the same weight as the
quantity of water which it displaces, and it is, therefore,
sustained in the water just as a balloon is sustained in the
atmosphere,—and this, too, at least to some extent, by
exactly parallel means, For man to navigate the air, the
machine by which he does so must have thus muck in
common with the balloon,—it must be as self-buoyant in
the element it is to travel through as a fish is in its element.
Therefore, although balloons cannot accomplish the nevi•
gation of the air, it can be effected only by the aid of
those light gases by means of which balloons are rendered
buoyant. The object in view can only be achieved by
some method of applying the lifting power of the light
gases more advantageously than this is done in the case of
balloons. That method can only consist in an alteration
of theform of the receptacles containing the gas. Instead
of being spheroidal, they must be more or less fish-shaped;
they must be flattened cylinders with paraboloidal ends.
In order to show clearly, by a readily intelligible illus-
tration, what influence this simple change of form would
have, let us suppose a hundred balloons, all of exactly the
same size, to be ranged in a row, like the carriages of a
railway train, and let the hundred balloons be all connected
with, and so all assist to support, one long, narrow
car. Such a train of balloons would represent the pro-
posed cylinder sufficiently nearly,—especially as the
" cylinder" would itself virtually consist of a number of
distinct bags of gas connected together, the chief differ-
ence between it and the train of balloons being that in
it space would be economized, and steadiness of lifting
power and uniformity of motion secured, by their being no
suck interstices between the bags of gas composing it as
there would in the case of the train of balloons. It is obvi-
ous that, to the motion through it, end-foremost, of the sup-
posed train of balloons, the atmosphere would be able to
oppose only the same amount of resistance as it would oppose
to the motion through it of any one of the balloons singly,
No more force therefore would be required to propel the
train of balloons than would be required to propel
a single balloon, but the train would be able to lift an engine
for the supply of that force a hundred times heavier than
the single balloon could lift.' As the power of an engine in-
creases much more rapidly than its weight, there could thus
be applied to the propulsion of the train of balloons several
hundred times more force than could be applied to the pro-
pulsion of any one of them by itself,
I have said that the aerial cylinder which this article is
written to suggest would consist, in effect, of a combination
of a number of separate bags of gas. It would never do to
make it consist simply of one huge long narrow bag, because
such a bag, if filled with light gas and allowed to rise into
the atmosphere, instead of floating horizontally, as the cy-
linder must, in order to be available as a means of navigat-
ing the air, would float with its longest axis vertical to the
earth's surface. To prevent its doing that, the 091iter
when not actually composed of a number of distinct bags;
combined together, should be divided into a out—dr be
higher compartments, or cells, each of which t'het`"i_
to
higher than it was wide—should be longer,a?al
say, in the direction perpendicular
Win the longest
rt
axis of the cylinder as a whole
thanb thissimple direction. It will readily be seed thatheyld be
that it
thanu
horizontally.
impossible
ar-
rangement it would be secured
for the cylinder to float in any other way
That; such cylinder could be propelled, and by such means
for the supply of motive force as w. e ha already at our
command, is not a me
rely speculateve opunon—an enthu-
siastic conviction, which may or may not be well-founded
which have long been established, and
hltavreesbtseeonn dtastda
by actual experience thousands of times,
It is based
on the following established facts :--
ist. The weight of a cubic foot of hydrogen is 36.5
grains, and that of a cubic foot of atmospheric
air 523
grains. A cubic foot of hydrogen will, therefore, sustain
in the atmosphere a heavy body weighing 4865 grains,
being the difference between its own weight and that of the
'
volume of air which it displaco. There are 7,000 grains
to the pound avoirdupois, and 14 5 times 486.5 is 7,054.25.
Consequently 14; cubic feet of hydrogen will sustain a
pound and 51'25 grains.
2d. A body moving through the atmosphere at the rate
of one mile an hour, and presenting a flat surface for the
atmosphere to act upon in opposing its motion, experiences
a resistance of .005 of a pound on every square foot of such
surface, and this resistance increases as the square of the
velocity.

301. The resistance to motion through the atmosphtre
is greatly modified by the form of the moving body. The
form that gives least resistance is nearly that of a parabola,
or a form somewhat resembling the breast of a duck or the
head of a fish. The body should also taper backwards, like
the body of a fish." The resistance to a paraboloid is one-
third less than the resistance to a plane surface equal in
extent to a section of the paraboloidal body, taken at its
widest part.

From these data, both the lifting power of a cylinder of
any given dimensions, and the resistance whioh the at-
mosphere would oppose to its motion, at any given speed,
can be readily calculated.
Let us suppose, then, a cylinder of the kind indicated to