AIR-SHIPS AND FLYING MACHINES
WHEN we read of the great inventions of the past, we are apt
to think that they would in any case have been invented some time or
other, even though the great inventors themselves had never lived.
But to tell the truth, each inventor had before him a great number of
difficulties which he could only overcome by patient and persistent
effort. It often happened that some attempt to solve the problem had
been made before him, and had failed. Such a failure would lead men to
believe that success was impossible. Somebody would try to prove that
the problem could not possibly be solved, and that one might as well
give it up as hopeless. It is just this kind of attitude which is most
disturbing to inventors and discoverers. They are surrounded by friends
who never cease to tell them that they are simply wasting their time in
trying to solve a problem which cannot be solved.
Such a problem is that of flying through the air. The birds have solved
it long ago, but even a few yearn ago it was taken for granted that no
machine or engine could be built which would lift its own weight into
the upper air. But within the last year the problem of human flight has
been solved completely, and probably in a few years’ time the flying
machine will be seen by nearly everybody every day.
This achievement means an entirely new development of civilisation.
We are fortunate to live in the time of an invention which is more
important than the steam-engine or the steam-ship, and will do more
to bring people together than the telephone or the telegraph. We are
doubly fortunate in being able to watch from day to day the manner
in which the various difficulties of flying are overcome one by one.
Instead of reading of great discoverers of far-off times, we can read
about the triumphs of the great men of our own time. We can follow and
admire the work of the heroes of science of to-day.
The first instrument which enabled man to rise into the air like a bird
was the balloon. Nobody knows when the first balloon was sent up. But
it is reported that at Pekin, the capital of China, a balloon was sent
up at the coronation of the Emperor of China so long ago as the year
1306. In the year 1709, a priest of Lisbon is reported to have ascended
into the air in a balloon filled with hot air, but the first authenic
account we have of such an event dates from the year 1783.
Several years before that, Cavendish in England had found that hydrogen
is fourteen times lighter than air, and that it therefore ascends
through air. This was proved by filling a soap bubble with hydrogen
instead of with air. It floated quickly up to the ceiling and then
burst. This experiment set many people thinking about the possibility
of getting things lifted up into the air by gas. Two of these people
were brothers of the name of Montgolfier, who owned a paper factory in
France. One day they made a great bag of paper and held it over the
fire, thinking that the smoke from the fire would raise the bag into
the air. But the paper was too heavy, and the balloon did not rise.
Most people would have been discouraged by such a failure, but the
brothers Montgolfier guessed the cause of it, and proceeded to manage
things better. They built another balloon in the shape of a box, with
its opening downwards, and this time they employed silk instead of
paper. They held it over a fire of straw and wool, thinking that such
a fire developed a kind of gas which was very light, or which was
repelled by the earth. They found, however, after a while, that the
nature of the fire did not matter so long as it was hot enough. They
found, in fact, that it was the hot air which really caused the balloon
to rise, and that a flame burns upwards simply because it is lighter
than air. How this should be so is quite clear from the principle of
Archimedes, according to which a body loses as much in weight as the
weight of the fluid it displaces.
We have seen already that the weight of the air inside an ordinary
sized room is about a hundredweight. If therefore we construct a
balloon of the same bulk as a room, and fill it with a gas much lighter
than air, the balloon will weigh less than its ordinary weight by about
a hundredweight. If the balloon together with a light gas which fills
it weighs 60 lbs., it will be able to lift 52 lbs., or rather it will
require 52 lbs. to keep the balloon down on the ground. By making the
air inside the balloon hot, about 45 lbs. of air can be made to balance
the pressure of the outside air, so that 60 or 70 lbs. may be the
weight of the balloon itself. But by using hydrogen the weight of the
gas can be reduced much further. For eight pounds of hydrogen exert the
same pressure as a hundredweight of air, so that these eight pounds of
hydrogen can lift 104 lbs.
The silk balloon constructed by the brothers Montgolfier rose up into
the air, but fell down again as soon as it cooled. They therefore made
a new balloon 40 feet high, constructing the envelope of packing-cloth
covered with paper. The lower end was open, and under it was hung
an iron cradle filled with moist straw and wool, which gave a slow
fire, and helped to keep up the heat of the balloon. The new balloon
rose into the air in June 1783, and soon sailed out of sight, bearing
a message up to the clouds that mankind was about to enter their
territory.
The news of this great success quickly reached Paris, and led to many
attempts to imitate and develop the striking invention. In Paris,
the work was taken up by the brothers Robert, makers of scientific
instruments, and Professor Charles, a young and promising physicist.
They made a balloon 12 feet in diameter and filled it with hydrogen
gas. It rose into the air and sailed away before a huge crowd of
people. A few days afterwards, the brothers Montgolfier brought to
Paris a giant balloon 72 feet high, which also rose into the air, but
was held back by ropes. A week after that they attached to the balloon
a car of wickerwork, in which they put a sheep, a cock, and a duck.
The balloon came to the ground somewhere out in the country, and all
the three animals alighted safe and sound.
The success of these first three navigators of the air encouraged the
human inventors of the balloon to venture themselves into cloudland,
and in November of the same year two Frenchmen ascended in a
fire-balloon and sailed over Paris across the river Seine. To show that
the same could be done in a balloon filled with hydrogen, Charles and
Robert made an ascent in a gas balloon a few days later. The balloon
was made in lengths of red and yellow silk. It was provided with a net,
to which the car was attached, with a valve for letting out the gas,
with a barometer for measuring the height, and with bags of sand. The
sand was taken as ballast, and was used to lessen the weight of the
balloon when it was sinking too quickly.
The great hopes built upon the balloon were not fulfilled for many
years. Benjamin Franklin, when he first saw a balloon, said he had seen
an infant which he hoped to see grow into a giant. But for ninety years
no decided improvement was made in the construction of the balloon.
Bold investigators of the air were found to cross the Channel from
Dover to Calais, or from London to Germany, as Green did in 1836 in a
giant balloon filled with coal-gas. Some great heights were reached.
In 1862 two Englishmen named Glaisher and Coxwell rose to a height of
seven miles, the greatest height ever attained by people in a balloon.
Their pulses rose till they gave 110 beats per minute instead of about
70 or 80 beats per minute. Their faces became purple, and finally
Glaisher became unconscious. Coxwell lost the use of his hands in the
extreme cold of the upper air, but he managed to pull the valve rope
with his teeth, and so they both returned safely to Mother Earth.
During the Franco-German war a number of balloons were sent up from
Paris when it was besieged by the Germans. These balloons carried no
fewer than two and a half million letters into the provinces of France.
But the people in the provinces could not answer these letters, as no
balloon could be relied upon to reach Paris. It is not surprising,
therefore, that after the conclusion of the war, the French people
should have made many efforts to construct balloons which could be
guided to any particular destination. One such balloon was built in
1872, and another eleven years afterwards, but those balloons were not
suitably constructed, and the engines and screw propellers were not
powerful enough to take them against the wind.
It was only when motor cars were built in great numbers that people
acquired sufficient experience to build very light and powerful
engines suitable for propelling balloons. This shows how one class of
inventors may help another class. A balloon which can be driven in any
chosen direction is called an “air-ship.” Many such air-ships have
been built within the last few years. They are shaped very much like a
cigar. Some of them have cars made of light rods of steel or aluminium,
and such air-ships have been navigated from one city to another over
distances of sixty miles.
One of the most remarkable of these air-ships is that constructed by
Count Zeppelin, a German officer (Fig. 76). It is 420 feet long, and
38 feet high. It is cylindrical in shape, and is covered with silk or
gold-beater’s skin stretched over a stiff frame of aluminium rods.
It is divided into sixteen air-tight compartments, so that if a hole
should be cut in it at any point, the whole balloon would come to the
ground very slowly. One such balloon travelled down the Rhine in August
1908 for over eleven hours. On its homeward journey it was caught in
a storm and burnt up, but it was thought that it was built on a good
plan, and the Germans at once set to work to build more ships of the
same kind. In 1909 one of these made a trip from the Lake of Constance,
in Switzerland, across Germany, to a place almost within sight of
Berlin.
But while inventors were busy constructing balloons, the solution of
the problem of flight was undertaken along an entirely different line.
[Illustration: Fig. 76.--Zeppelin II. on its Flight over Cologne.]
Many men did not see why we should not to some extent imitate the
flight of our successful rivals, the birds. It is true that from the
earliest times many men have tried to make wings that could fly, but
these attempts always ended in failure or disaster. The human body is
too heavy in proportion to the power of the muscles. Birds are much
stronger in proportion to their weight than we are. Their bones are
built on a lighter plan, and there is no probability that we should
be able to alter the construction of our own bones for the purposes
of flight. Nor is that necessary. There are many ways of keeping a
body afloat in air. Some birds can keep afloat for a long time without
flapping their wings at all, and most people are acquainted with the
trick of making a card fly through the air by giving it a rapid turning
motion.
It was an American, Professor Langley, who first constructed a small
machine which could fly through the air by means of its own mechanism.
He found that the faster a flat surface is moved through the air in
a horizontal direction, the less power it requires to keep it up. He
concluded that if a machine is provided with horizontal wings, and
driven very fast through the air, it will not require a very powerful
engine to keep it up once a fairly high speed is attained. He launched
his apparatus over a lake, and had the pleasure of seeing it fly for
miles before it fell into the water. When this principle had been
established other inventors straightway proceeded to apply it.
Two American motor manufacturers of the name of Orville and Wilbur
Wright constructed a machine capable of carrying a man. Two years ago
the first public trial of a flying machine was successfully made in
Paris, when Mr. Santos Dumont, a young Brazilian balloonist, flew
several hundred yards in a machine heavier than air. This machine
consisted of a number of boxes open at both ends and covered with
tightly-stretched canvas.
[Illustration: Fig. 77.--Blériot’s Aeroplane leaving France.]
At that time it was found impossible to steer such a machine. But on
December 30, 1907, Mr. Henry Farman succeeded at last in Paris in
describing a complete circle in the air, covering a distance of more
than half a mile, without once touching the ground. In July 1908 Mr.
Farman remained in the air twenty minutes, covering a distance of
eleven miles. This speed was afterwards increased to sixty miles an
hour. Meanwhile Mr. Wilbur Wright had gone to France, and he soon
eclipsed all the French records. On September 16, 1908, he flew a
distance of a mile and a half with a passenger on board, and on
September 21 he remained in the air one hour and a half, covering a
distance of fifty-six miles. He remained in the air after darkness
had set in, and it was strange to see his machine fly about like some
gigantic night-bird. On the last day of 1908, Mr. Wright accomplished a
flight lasting two hours twenty-three minutes, and covered a distance
of nearly seventy-eight miles. This has since been exceeded both as
regards distance and duration, and there seems every prospect that
flights lasting several hours will soon be of common occurrence. On
July 25, 1909, M. Louis Blériot, a French engineer, performed the
great feat of crossing the English Channel from Calais to Dover in
thirty-three minutes, in an aeroplane of his own construction. For ten
minutes of the flight he was entirely out of sight of land.
Civilisation has now arrived at a new stage of immense importance.
For the first time in its long history mankind has entered into full
possession of the realm of air. We have now a new road which needs no
repairing, and extends all round the globe. Our race enters on a new
era, and nobody can say what great changes and improvements in our
daily life are yet in store for us.
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