This new disaster left the faith and loyalty of the German people unshaken. But it did decidedly estrange the scientific world from Count von Zeppelin and all his works. It was pointed out, with truth, that the accident paralleled precisely one which had demolished the _Severo Pax_ airship ten years earlier, and which had caused French inventors to establish a hard and fast rule against incorporating in an airship's design any inclosed s.p.a.ce in which waste gas might gather. This rule and its reason were known to Count von Zeppelin and by ignoring both he lent new colour to the charge, already current in scientific circles, that he was loath to profit by the experiences of other inventors.

Whether this feeling spread to the German Government it is impossible to say. Nor it is easy to estimate how much official confidence was shaken by it. The government, even before the war, was singularly reticent about the Zeppelins, their numbers and plans. It is certain that orders were not withheld from the Count.

Great numbers of his machines were built, especially after the war was entered upon. But he was not permitted longer to have a monopoly of government aid for manufacturers of dirigibles. Other types sprung up, notably the Schutte-Lanz, the Gross, and the Pa.r.s.eval.

But being first in the field the Zeppelin came to give its name to all the dirigibles of German make and many of the famous--or infamous--exploits credited to it during the war may in fact have been performed by one of its rivals.

It would be futile to attempt to enumerate all these rivals here.

Among them are the semi-rigid Pa.r.s.eval and Gross types which found great favour among the military authorities during the war. The latter is merely an adaptation of the highly successful French ship the _Lebaudy_, but the Pa.r.s.eval is the result of a slow evolution from an ordinary balloon. It is wholly German, in conception and development, and it is reported that the Kaiser, secretly disgusted that the Zeppelins, to the advancement of which he had given such powerful aid, should have recorded so many disasters, quietly transferred his interest to the new and simpler model. Despite the hope of a more efficient craft, however, both the Gross and the Pa.r.s.eval failed in their first official trials, though later they made good.

The latter ship was absolutely without any wooden or metallic structure to give her rigidity. Two air ballonets were contained in the envelope at bow and stern and the ascent and descent of the ship was regulated by the quant.i.ty of air pumped into these. A most curious device was the utilization of heavy cloth for the propeller blades. Limp and flaccid when at rest, heavy weights in the hem of the cloth caused these blades to stand out stiff and rigid as the result of the centrifugal force created by their rapid revolution.

One great military advantage of the Pa.r.s.eval was that she could be quickly deflated in the presence of danger at her moorings, and wholly knocked down and packed in small compa.s.s for shipment by rail in case of need. To neither of these models did there ever come such a succession of disasters as befell the earlier Zeppelins. It is fair to say however that prior to the war not many of them had been built, and that both their builders and navigators had opportunity to learn from Count von Zeppelin's errors.

Among the chief German rivals to the Zeppelin is the Schutte-Lanz, of the rigid type, broader but not so long as the Zeppelin, framed of wood bound with wire and planned to carry a load of five or six tons, or as many as thirty pa.s.sengers. No. I of this type met its fate as did so many Zeppelins by encountering a storm while improperly moored. Called to earth to replenish its supply of gas it was moored to an anchor sunk six feet in the ground, and as an additional precaution three hundred soldiers were called from a neighbouring barracks to handle it. It seems to have been one of the advantages of Germany as a place in which to manoeuvre dirigibles, that, even in time of peace, there were always several hundred soldiers available wherever a ship might land. But this force was inadequate. A violent gust tore the ship from their hands. One poor fellow instinctively clung to his rope until one thousand feet in the air when he let go. The ship itself hovered over the town for an hour or more, then descended and was dashed to pieces against trees and stone walls.

The danger which was always attached to the landing of airships has led some to suggest that they should never be brought to earth, but moored in mid-air as large ships anchor in midstream. It is suggested that tall towers be built to the top of which the ship be attached by a cable, so arranged that she will always float to the leeward of the tower. The pa.s.sengers would be landed by gangplanks, and taken up and down the towers in elevators. Kipling suggests this expedient in his prophetic sketch _With the Night Mail_. The airship would only return to earth--as a ship goes into dry dock--when in need of repairs.

A curious mishap that threatened for a time to wreck the peace of the world, occurred in April, 1913, when a German Zeppelin was forced out of its course and over French territory. The right of alien machines to pa.s.s over their territory is jealously guarded by European nations, and during the progress of the Great War the Dutch repeatedly protested against the violation of their atmosphere by German aviators. At the time of this mischance, however, France and Germany were at peace--or as nearly so as racial and historic antipathies would permit. Accordingly when officers of a brigade of French cavalry engaged in manoeuvring near the great fortress of Luneville saw a shadow moving across the field and looking up saw a huge Zeppelin betwixt themselves and the sun they were astonished and alarmed. Signs and faint shouts from the aeronauts appeared to indicate that their errand was at least friendly, if not involuntary. The soldiers stopped their drill; the townspeople trooped out to the Champs de Mars where the phenomenon was exhibited and began excitedly discussing this suspicious invasion. Word was speedily sent to military headquarters asking whether to welcome or to repel the foe.

[Ill.u.s.tration: U. & U.

_British Aviators about to Ascend._

_Note position of gunner on lower seat._]

Meantime the great ship was drifting perilously near the housetops, and the uniformed officers in the cars began making signals to the soldiers below. Ropes were thrown out, seized by willing hands and made fast. The crew of Germans descended to find themselves prisoners. The international law was clear enough. The ship was a military engine of the German army. Its officers, all in uniform, had deliberately steered her into the very heart of a French fortress. Though the countries were at peace the act was technically one of war--an armed invasion by the enemy. Diplomacy of course settled the issue peacefully but not before the French had made careful drawings of all the essential features of the Zeppelin, and taken copies of its log. As Germany had theretofore kept a rigid secrecy about all the details of Zeppelin construction and operation this angered the military authorities beyond measure. The unlucky officers who had shared in the accident were savagely told that they should have blown the ship up in mid-air and perished with it rather than to have weakly submitted it to French inspection. They suffered court-martial but escaped with severe reprimands.

The story of the dirigibles of France and Germany is practically the whole story of the development to a reasonable degree of perfection of the lighter-than-air machine. Other nations experimented somewhat, but in the main lagged behind these pioneers. Out of Spain indeed came a most efficient craft--the Astra-Torres, of which the British Government had the best example prior to the war, while both France and Russia placed large orders with the builders. How many finally went into service and what may have been their record are facts veiled in the secrecy of wartime. Belgium and Italy both produced dirigibles of distinctive character. The United States is alone at the present moment in having contributed nothing to the improvement of the dirigible balloon.

CHAPTER V

THE DEVELOPMENT OF THE AIRPLANE

The story of the development of the heavier-than-air machine--which were called aeroplanes at first, but have been given the simpler name of airplanes--is far shorter than that of the balloons. It is really a record of achievement made since 1903 when the plane built by Professor Langley of the Smithsonian Inst.i.tution came to utter disaster on the Potomac. In 1917, at the time of writing this book, there are probably thirty distinct types of airplanes being manufactured for commercial and military use, and not less than fifty thousand are being used daily over the battlefields of Europe.

No invention save possibly the telephone and the automobile ever attained so prodigious a development in so brief a time. Wise observers hold that the demand for these machines is yet in its infancy, and that when the end of the war shall lead manufacturers and designers to turn their attention to the commercial value of the airplane the flying craft will be as common in the air as the automobiles at least on our country roads.

The idea of flying like a bird with wings, the idea basicly underlying the airplane theory, is old enough--almost as old as the first conception of the balloon, before hydrogen gas was discovered.

In an earlier chapter some account is given of early experiments with wings. No progress was made along this line until the hallucination that man could make any headway whatsoever against gravity by flapping artificial wings was definitely abandoned. There was more promise in the experiments made by Sir George Cayley, and he was followed in the first half of the nineteenth century by half a dozen British experimenters who were convinced that a series of planes, presenting a fixed angle to the breeze and driven against it by a sufficiently powerful motor, would develop a considerable lifting power. This was demonstrated by Henson, in 1842, Stringfellow, in 1847, Wenham, who arranged his planes like slats in a Venetian blind and first applied the modern term "aeroplane" to his invention, and Sir Hiram Maxim, who built in 1890 the most complicated and impressive looking 'plane the world has yet seen.

But though each of these inventors proved the theorem that a heavier-than-air machine could be made to fly, all failed to get practical results because no motor had then been invented which combined the necessary lightness with the generation of the required power.

In America we like to think of the brothers Wright as being the true inventors of the airplane. And indeed they did first bring it to the point of usefulness, and alone among the many pioneers lived to see the adoption of their device by many nations for serious practical use. But it would be unjust to claim for them entire priority in the field of the glider and the heavier-than-air machine. Professor Langley preceded them with an airplane which, dismissed with ridicule as a failure in his day, was long after his death equipped with a lighter motor and flown by Glenn Curtis, who declared that the scientist had solved the problem, had only the explosive engine been perfected in his time.

Despite, however, the early period of the successful experiments of the Wrights and Professor Langley, it would be unjust for America to arrogate to herself entire priority in airplane invention. Any story of that achievement which leaves out Lilienthal, the German, and Pilcher, the Englishman, is a record in which the truth is subordinated to national pride.

[Ill.u.s.tration: Langley's Airplane.]

Otto Lilienthal and his brother Gustav--the two like the Wrights were always a.s.sociated in their aviation work--had been studying long the problem of flight when in 1889 they jointly published their book _Bird Flight as the Basis of the Flying Art_. Their investigations were wholly into the problem of flight without a motor. At the outset they even harked back to the long-abandoned theory that man could raise himself by mere muscular effort, and Otto spent many hours suspended at the end of a rope flapping frantically a pair of wings before he abandoned this effort as futile. Convinced that the soaring or gliding of the birds was the feat to emulate, he made himself a pair of fixed, bat-like wings formed of a light fabric stretched over a willow frame. A tail composed of one vertical and one horizontal plane extended to the rear, and in the middle the aviator hung by his armpits, in an erect position. With this device he made some experimental glides, leaping from slight eminences. With his body, which swung at will from its cushioned supports, he could balance, and even steer the fabric which supported him, and accomplished long glides against the wind.

Not infrequently, running into the teeth of the breeze down a gentle slope he would find himself gently wafted into the air and would make flights of as much as three hundred yards, steering to either side, or rising and falling at will. He was even able to make a circuitous flight and return to his starting place--a feat that was not accomplished with a motor-driven airplane until years later.

Lilienthal achieved it with no mechanical aid, except the wings. He became pa.s.sionately devoted to the art, made more than two thousand flights, and at the time of his death had just completed a motor-driven airplane, which he was never able to test. His earlier gliding wings he developed into a form of biplane, with which he made several successful flights, but met his death in 1896 by the collapse of this machine, of the bad condition of which he had been warned.

[Ill.u.s.tration: Kadel & Herbert.

_French Airdrome near the Front._]

Lilienthal was more of a factor in the conquest of the air than his actual accomplishments would imply. His persistent experiments, his voluminous writings, and above all his friendly and intelligent interest in the work of other and younger men won him a host of disciples in other lands who took up the work that dropped from his lifeless hands.

[Ill.u.s.tration: Lilienthal's Glider.]

In England Percy S. Pilcher emulated the Lilienthal glides, and was at work on a motor-propelled machine when he was killed by the breakage of a seemingly unimportant part of his machine. He was on the edge of the greater success, not to that moment attained by anyone, of building a true airplane propelled by motor. Many historians think that to Lilienthal and Pilcher is justly due the t.i.tle "the first flying men." But Le Bris, a French sailor, utterly without scientific or technical equipment, as far back as 1854 had accomplished a wonderful feat in that line. While on a cruise he had watched an albatross that followed his ship day after day apparently without rest and equally without fatigue. His imagination was fired by the spectacle and probably having never heard of the punishment that befell the Ancient Mariner, he shot the albatross. "I took the wing," he wrote later, "and exposed it to the breeze, and lo, in spite of me, it drew forward into the wind; notwithstanding my resistance it tended to rise. Thus I had discovered the secret of the bird. I comprehend the whole mystery of flight."

A trifle too sanguine was sailor Le Bris, but he had just the qualities of imagination and confidence essential to one who sets forth to conquer the air. Had he possessed the accurate mind, the patience, and the pertinacity of the Wrights he might have beaten them by half a century. As it was he accomplished a remarkable feat, though it ended in somewhat laughable failure. He built an artificial bird, on the general plan of his albatross. The wings were not to flap, but their angles to the wind were controlled by a system of levers controlled by Le Bris, who stood up in the basket in the centre. To rise he required something like the flying start which the airplanes of to-day get on their bicycle wheels before leaving the ground. As Le Bris had no motor this method of propulsion was denied him, so he loaded the apparatus in a cart, and fastened it to the rail by a rope knotted in a slip knot which a jerk from him would release. As they started men walked beside the cart holding the wings, which extended for twenty-five feet on either side. As the horses speeded up these a.s.sistants released their hold. Feeling the car try to rise under his feet Le Bris cast off the rope, tilted the front end of the machine, and to his joy began to rise steadily into the air. The spectators below cheered madly, but a note of alarm mingled with their cheers, and the untried aviator noticed a strange and inexplicable jerking of his machine. Peering down he discovered, to his amaze, a man kicking and crying aloud in deadly fear. It was evident that the rope he had detached from the cart had caught up the driver, who had thus become, to his intense dismay, a partner in the inventor's triumph.

Indeed it is most possible that he contributed to that triumph for the ease and steadiness with which the machine rose to a height estimated at three hundred feet suggests that he may have furnished needed ballast--acted in fact as the tail to the kite. Humanity naturally impelled Le Bris to descend at once, which he did skilfully without injuring his involuntary pa.s.senger, and only slightly breaking one of the wings.

[Ill.u.s.tration: U. & U.

_A German War Zeppelin._]

Had Le Bris won this success twenty years later his fame and fortune would have been secure. But in 1854 the time was not ripe for aeronautics.

Le Bris was poor. The public responded but grudgingly to his appeals for aid. His next experiment was less successful--perhaps for lack of the carter--and he ultimately disappeared from aviation to become an excellent soldier of France.

[Ill.u.s.tration: Photo by Press Ill.u.s.trating Service.

_A French Observation Balloon Seeking Submarines._]

Perhaps had they not met with early and violent deaths, the Lilienthals and Pilcher might have carried their experiments in the art of gliding into the broader domain of power flight. This however was left to the two Americans, Orville and Wilbur Wright, who have done more to advance the art of navigating the air than all the other experimenters whose names we have used. The story of the Wright brothers is one of boyhood interest gradually developed into the pa.s.sion of a lifetime. It parallels to some degree the story of Santos-Dumont who insisting as a child that "man flies" finally made it a fact. The interest of the Wrights was first stimulated when, in 1878, their father brought home a small toy, called a "helicopter,"

which when tossed in the air rose up instead of falling. Every child had them at that time, but curiously this one was like the seed which fell upon fertile soil. The boys went mad, as boys will, on the subject of flying. But unlike most boys they nurtured and cultivated the pa.s.sion and it stayed with them to manhood. From helicopters they pa.s.sed to kites, and from kites to gliders. By calling they were makers and repairers of bicycles, but their spare time was for years devoted to solving the problem of flight. In time it became their sole occupation and by it they won a fortune and world-wide fame. Their story forms a remarkable testimony to the part of imagination, pertinacity, and courage in winning success.

After years of tests with models, and with kites controlled from the ground, the brothers had worked out a type of glider which they believed, in a wind of from eighteen to twenty miles an hour, would lift and carry a man. But they had to find a testing ground. The fields near their home in Ohio were too level, and their firm unyielding surface was not attractive as a cushion on which to light in the event of disaster. Moreover the people round about were getting inquisitive about these grown men "fooling around" with kites and flying toys. To the last the Wrights were noted for their dislike of publicity, and it is entirely probable that the sneering criticisms of their "level headed" and "practical" neighbours had a good deal to do with rooting them in this distaste.

Low steep hills down the sides of which they could run and at the proper moment throw themselves upon their glider; a sandy soil which would at least lessen the shock of a tumble; and a vicinage in which winds of eighteen miles an hour or more is the normal atmospheric state were the conditions they sought. These they found at a little hamlet called Kitty-Hawk on the coast of North Carolina. There for uncounted centuries the tossing Atlantic had been throwing up its snowy sand upon the sh.o.r.e, and the steady wind had caught it up, piled it in windrows, rolled it up into towering hills, or carried it over into the dunes which extended far inland. It was a lonely spot, and there secure from observation the Wrights pitched their camp. For them it was a midsummer's holiday. Not at first did they decide to make aviation not a sport but a profession. To their camp came visitors interested in the same study, among them Chanute, a well-known experimenter, and some of his a.s.sociates. They had thought to give hours at a time to actual flight. When they closed their first season, they found that all their time spent in actual flight footed up less than an hour. Lilienthal, despite all he accomplished, estimated that he, up to a short time before his death, spent only about five hours actually in the air. In that early day of experimentation a glide covering one hundred feet, and consuming eight or ten seconds, was counted a triumph.

[Ill.u.s.tration: Chanute's Glider.]

But the season was by no means wasted. Indeed such was the estimate that the Wrights put upon it that they folded their tents determined that when they returned the year following it would be as professionals, not amateurs. They were confident of their ability to build machines that would fly, though up to that time they had never mounted a motor on their aircraft.

In the clear hot air of a North Carolina midsummer the Wrights used to lie on their backs studying through gla.s.ses the methods of flight of the great buzzards--filthy scavenger birds which none the less soaring high aloft against a blue sky are pictures of dignity and grace.

Bald eagles, ospreys, hawks, and buzzards give us daily exhibitions of their powers [wrote Wilbur Wright]. The buzzards were the most numerous, and were the most persistent soarers.

They apparently never flapped except when it was absolutely necessary, while the eagles and hawks usually soared only when they were at leisure. Two methods of soaring were employed. When the weather was cold and damp and the wind strong the buzzards would be seen soaring back and forth along the hills or at the edge of a clump of trees. They were evidently taking advantage of the current of air flowing upward over these obstructions. On such days they were often utterly unable to soar, except in these special places. But on warm clear days when the wind was light they would be seen high in the air soaring in great circles.

Usually, however, it seemed to be necessary to reach a height of several hundred feet by flapping before this style of soaring became possible. Frequently a great number of them would begin circling in one spot, rising together higher and higher till finally they would disperse, each gliding off in whatever direction it wished to go. At such times other buzzards only a short distance away found it necessary to flap frequently in order to maintain themselves. But when they reached a point beneath the circling flock they began to rise on motionless wings. This seemed to indicate that rising columns of air do not exist everywhere, but that the birds must find them. They evidently watch each other and when one finds a rising current the others quickly make their way to it. One day when scarce a breath of wind was stirring on the ground we noticed two bald eagles sailing in circling sweeps at a height of probably five hundred feet. After a time our attention was attracted to the flashing of some object considerably lower down. Examination with a field-gla.s.s proved it to be a feather which one of the birds had evidently cast. As it seemed apparent that it would come to earth only a short distance away, some of our party started to get it. But in a little while it was noted that the feather was no longer falling, but on the contrary was rising rapidly. It finally went out of sight upward. It apparently was drawn into the same current in which the eagles were soaring and was carried up like the birds.

It was by such painstaking methods as these, coupled with the mathematical reduction of the fruits of such observations to terms of angles and supporting planes, that the Wrights gradually perfected their machine. The first airplane to which they fitted a motor and which actually flew has been widely exhibited in the United States, and is to find final repose in some public museum.

Study it as you will you can find little resemblance in those rectangular rigid planes to the wings of a bird. But it was built according to deductions drawn from natural flight.

[Ill.u.s.tration: Photo by Paul Thompson.

_A German Taube Pursued by British Planes._]