It is now time we turn our attention from the airship to its important rival, the flying machine.

At first sight it may perhaps appear that so far the flying machine has accomplished less than the airship, and gives less promise of success, since up to the present time no flying machine has taken a man any distance into the air, or indeed done much more than just lift itself off the ground. Nevertheless those who have made a study of the matter are full of hope for the future. Many experts declare that already the limits of what can be done with the airship, which depends upon the lifting power of its gas to raise it and to sustain it in the air, are being reached. It has indeed been proved that on a calm day, or with only a light breeze, this form of sky vessel can be steered safely about the heavens, and doubtless as engines are constructed yet lighter and more powerful in proportion to their weight, more successful voyages still will be accomplished. But it is extremely doubtful whether an airship can ever be constructed which shall be able to stand against a gale of wind.

So long as a balloon sails only with the breeze it offers no resistance to the force of the wind, and can be made of the lightest and thinnest material. But directly it has to face the wind, and fight its way against it as an airship must do, then it has to be made of sufficient strength and rigidity to withstand the wind’s power, or it will be blown to pieces. To make so large a thing as an airship withstand a rough wind, it must be built of very strong and rigid materials. To do this means to add to the weight of the machine. To lift the increased weight, a larger machine which can hold more gas is needed. The larger the machine the more surface it offers to the wind, and the stronger therefore must be its construction. It will now be seen that we are arguing in a circle, and we can understand that a point must be reached in the making of airships when, with our present materials, the advantage gained by increase of strength will be more than counterbalanced by increased weight. On this point Sir Hiram Maxim says: “It is not possible to make a balloon, strong enough to be driven through the air at any considerable speed, at the same time light enough to rise in the air; therefore balloons must always be at the mercy of a wind no greater than that which prevails at least 300 days in the year;” adding, “Those who seek to navigate the air by machines lighter than air have, I think, come practically to the end of their tether.”

With the flying machine, on the contrary, the same difficulty does not arise. Since it is at all times heavier than air, and is kept aloft simply by its motive power and mechanism, its weight is of no consequence, provided only its engine is sufficiently powerful. It may, therefore, be built as rigidly as need be, while, from its size—which is much smaller in proportion to its lifting power than in the case of the airship—and also from its construction, it is much less liable to be affected by the wind.

In constructing a flying machine which is heavier than air the inventor has before him two examples of bodies which, though heavier than the atmosphere, yet contrive to rise upwards into the sky; these are, firstly, birds, and secondly, the familiar schoolboy toys, kites. To imitate the flying powers of birds and kites, he must first understand the means by which their flight is accomplished; and he will find, on examination, that to a large extent the same principle underlies each—the principle of what is termed the “aeroplane.”

As we watch birds—especially large birds, as hawks and gulls—winging their way about the sky, we may notice that their flight is accomplished in two ways; either they are moving through the air by flapping their wings up and down, or else with wings wide outstretched they are soaring or sailing in the air for long times together without apparently moving their wings at all. Certain birds, such as vultures and albatrosses, possess this power of soaring flight to an extraordinary degree, and the exact way in which they keep themselves poised aloft is indeed still a mystery. We cannot, however, as we watch, say, a hawk, hovering in the air with motionless wing, help being struck by its resemblance to the schoolboy’s kite, kept afloat high in the sky by the action of the wind properly applied to its surface, and we can at once see that the bird makes use of the same principle as the kite in its soaring or hovering flight. Indeed, just as a kite sinks to earth when the wind drops, so in a dead calm even an albatross has to flap its wings to keep afloat.

It is to the principle of the kite, therefore, that the inventor of the flying machine must turn. He must adapt the same principle to his apparatus, and this he does in his aeroplane, which, as will be seen, is an all-important part of his machine, and which, in its simplest form, is nothing more or less than a kite.

We know that if a light flat body, such as a kite, is lying upon the ground, and the wind gets under it so as to tilt it, it will be lifted by the wind into the air. The string of a kite is so adjusted that as the kite rises it is still held at an angle to the wind’s force, and so long as the kite remains tilted at the necessary angle so long it will continue to rise or poise itself in the air while the wind blows. When schoolboys fly their kites they choose an exposed spot, and a day when the wind is blowing freshly and steadily. One boy throws the kite into the air, while another, holding the string to which it is fastened, draws it tight by running with it against the wind. By this means the kite, if rightly adjusted, is held at the proper angle to the wind, and started without dragging along the ground to begin with. As soon as the wind has fairly caught the kite and carried it up into the air, the boy who holds the string need run no longer, but if the breeze suddenly fails, and the kite begins to drop, he may still keep his toy aloft by running quickly along and dragging the kite after him; the artificial wind he thus creates making up for the lack of the other.

Now let us suppose that there is no string to hold the kite in proper position, and no boy to run with it; but that their places are supplied by a motor and propeller to drive it through the air; while at the same time it is so balanced as to preserve a fitting angle against a wind of its own making. We should then have a true flying machine, heavier than air, and yet capable of sailing through the sky.

This is the kind of flying machine that inventors at the present moment are trying to produce. They have, in their machines, to reproduce artificially two essential conditions that cause a kite to fly. They have to provide a substitute for the strength of the wind, and also a substitute for the pull of the string which keeps the kite at the best angle to profit by that strength. The first they achieve by using a suitable engine or motor, and the second by supplying it with what are called “aeroplanes”—large flat surfaces, light but rigid, inclined at a suitable angle to the horizon. By the use of these the power of the engine is employed to best advantage in causing the machine to sail through the sky.

The great advantage of the aeroplane over any other mode of flying is thus described by Major Baden-Powell, one of our greatest living authorities on aeronautical matters: “When people realise that in the case of the aeroplane a contrivance like the awning of a small steam launch is capable of supporting the man and the engines, and that in the case of the balloon a mass like a big ship is necessary to lift the same weight, one can readily understand the advantages of the aeroplane, especially when to the drawbacks of the bulky balloon are added the great difficulties inherent in the retention of a large volume of expensive, inflammable, and subtle gas, ever varying in its density.”

The most successful inventors of flying machines at the present day are all Americans, though one of them has made his experiments on this side of the Atlantic. They are Sir Hiram Maxim, inventor of the famous gun, and one of the greatest mechanicians living; Professor Langley, Secretary of the Smithsonian Institute, Washington; and the brothers Wright.

Mr. Maxim, as he then was, commenced his experiments in the early nineties. As we have already shown, he went to Nature for his guide, and in constructing his flying machine took as his analogy the flight of birds. Birds urge their way onwards in the air by reason of the strength of their wings. A flying machine must do the same by the power of its engine; and as a bird’s wings must be strong in proportion to the bird’s weight, so the strength or horse-power of the engine must stand in a certain proportion to the number of pounds it weighs. Mr. Maxim’s first task, therefore, was to discover what proportion this must be, and by his experiments he arrived at a conclusion which Professor Langley in America, working at the same task at the same time, but quite independently, had also proved to be true, namely, that the faster a machine travels through the air the greater weight it may carry; or, in other words, the quicker a body moves through the atmosphere the less tendency will it have to fall to the ground. A quick-flying bird like an albatross, therefore, flies with less exertion, and so could carry a greater weight, than a slow-moving bird like a goose. It must therefore be to the advantage of the flying machine that its engines should attain as great a speed as possible.

Maxim’s next task was to construct a suitable engine. Light but powerful engines had not then reached the pitch of perfection they have now, and his results proved at the time a perfect revelation of what could be done in this direction, and led to great advances being made.

Next came the designing of the great machine itself. It was an enormous apparatus, weighing over three tons, capable of carrying three men, and supported by no less than 4000 square feet of aeroplanes, placed one above the other. Its steam-engine was of 363 horse-power, and worked two screws of nearly 18 feet in diameter. Before such a machine could rise from the ground it must first have attained a very great forward impetus, and this it was to receive by running at a great speed on wheels along a railway track specially laid down for it. To prevent the apparatus rising unduly, a reversed rail was erected a short distance above, on which the machine would begin to run as soon as it lifted itself off the lower track. Along this railway the flying machine was tested, and it was found that as soon as a speed of thirty-six miles an hour was reached the wheels were lifted clear off the ground, and were running only upon the upper rail. On the last occasion a speed of forty-two miles an hour was attained, when the lifting power became so great that the restraining rail broke away altogether, and the great flying machine actually floated in the air for a few moments, “giving those on board the sensation of being in a boat,” until, steam being shut off, it fell to the ground and was broken.

The enormous expense of his experiments has not prevented Sir Hiram Maxim from repeating them, and he hopes soon to have a much improved machine. Nevertheless his experience and calculations have been of great value to those who would follow in his footsteps, and have proved the possibility of constructing a flying machine which shall fly by virtue of its own motion.

Meanwhile in America Professor Langley was experimenting, independently, almost on the same lines. He also was bent on producing a flying machine, but instead of starting to work upon a large apparatus like Maxim, he began by making models, and gradually worked his way up to bigger things. For many months he studied to understand the principle of those ingenious little toys sometimes seen, which, by means of the tension of a twisted india-rubber band, will keep afloat in the air for a few seconds. Next he constructed small models driven by steam, in which he found his great difficulty was in keeping down the weight. For years he persevered in his work without any great success, until in 1896 he produced a model machine which he called an “aerodrome.” It was quite small, weighing with its engine only 25 lbs., and measuring but 14 feet from tip to tip of its aeroplanes. The experiments were made over water, and the necessary momentum was given by dropping it from a platform 20 feet high. On more than one occasion this little flying machine rose with great steadiness in the face of the wind to a height of 100 feet, moving so smoothly that it might have carried a glass of water without spilling a drop; and then, the steam of its engine being exhausted, sank down gracefully upon the water, having flown about half a mile in a minute and a half. This success encouraged Professor Langley next to construct a full-sized flying machine on the same lines; but this on its first voyage plunged headlong into the water and was hopelessly damaged. The United States Government have since granted him a sum of money to continue his experiments.

Latest of all the airship inventors, and perhaps so far the most successful, are the brothers Wright. Up to the date of writing this the full details of their work are not yet made public, but it is known that on the 17th of December 1903, their machine, which consists of two large aeroplanes driven forward by an engine of sixteen horse-power, after being started along a short track on level ground, rose into the air and flew for about half a mile.

It remains for us now to make brief mention of how men have tried, and are still trying, to imitate the soaring or gliding flight of birds without the use of machinery to assist them. We have seen how an albatross can, when the wind is blowing, convert itself, as it were, into a kite, and keep aloft in the air for a while without moving its wings. Similarly many people have attempted, by attaching themselves to a large supporting surface or aeroplane, and casting themselves off from a height, to glide with the wind across wide stretches of country. In this mode of soaring flight some have made considerable progress. Herr Lilienthal, a German, was perhaps for a time the most successful. He started from small beginnings, jumping off a spring board a few feet high, and gradually increasing the height as he became more accustomed to his apparatus. Later he had a large artificial mound made specially for him, and from the top of this he would throw himself into the air, and with a favourable wind sail a distance of four hundred yards at a considerable height above the ground. Lilienthal’s experiments, however, came to a sad end. On August the 11th, 1896, after he had glided along in the air for about two hundred yards, a sudden gust of wind caught the wide-spread wings of his apparatus, and tilted it upwards. This caused him to lose his balance, and he fell from a height of sixty feet and broke his spine. A similar accident also caused the death, a few years later, of a young Englishman, Mr. Percy S. Pilcher, who had been following up Lilienthal’s experiments.

The greatest difficulty now to be overcome in solving the problem of human flight, whether with soaring apparatus or flying machine, may be summed up in one word—“balance.” Every schoolboy knows that the great art of kite-flying consists in so adjusting the point of attachment of the string and the length of the tail that his kite is properly balanced, and is not liable to turn over or “dip” when in the air. Every observer of birds, too, has noticed how largely the question of balance enters into their flying. A bird in the air is continually and instinctively adjusting its wings to its position, and to every puff of wind, even as a man on a bicycle is continually, though unconsciously, adjusting his handle-bar to the inequalities of the road; and as a cyclist requires practice before he can ride his machine, or a skater before he can keep his feet on the ice, so even a bird has to learn how to balance itself before it can use its wings.

Dwellers in the country are familiar with the way in which the parent birds teach their fledglings to fly, instructing them by example, and encouraging them in their first short flights until they have become familiar with their powers and can balance themselves aright in the air. And if even birds, with whom flying is an instinct, have to learn the art of balancing themselves in the air by practice, how much more so must such a clumsy creature as a man, to whom flying is entirely unnatural. Only by long and painful efforts can he ever hope to succeed at all, and unfortunately all such efforts are necessarily very dangerous. Many disastrous accidents have already occurred, and although great progress has been made, and the time may not now be far distant when, by means of improved machines, men will actually fly, it will be at the cost of much labour, and, it is to be feared, at the sacrifice of many more brave lives.