Chapter III: General Rule (7)

Night-flying is one of the most hazardous duties of the aviator, the chief danger being in the difficulty of making a safe landing. Night-landing fields are, as a rule, well illuminated by flood-lights, but near the front this was not always advisable or safe, and, owing to the difficulty of judging the distance of the machine above the ground in the darkness, accidents were by no means uncommon. In order to minimize this danger there was developed the “wing-tip flare,” which consists of a small cylinder of magnesium material in a metallic holder, one of which is fitted under each lower wing of the plane. The flares are ignited by an electric current and are controlled by push-buttons, one for each flare, in the pilot’s cockpit. In making a night-landing, when the pilot judges the plane to be but a few feet above the ground, he presses one of the buttons. The flare instantly ignites and for about fifty seconds burns with a light of approximately 20,000 candle-power, which, reflected on the ground by the under surface of the wing, enables the pilot to judge his distance and effect his landing without trouble.

The requirements of night-bombing have led to the development of a new and very interesting form of pyrotechnic known as the “airplane flare.” This flare, which weighs thirty-five pounds, is contained in a cylindrical case of sheet-iron about four feet long and five inches in diameter. The flare consists of an illuminating charge, capable of giving 32,000 candle-power for approximately ten minutes, which is attached to a silk parachute twenty feet in diameter. The cylinder is attached to the airplane by a light release mechanism similar to those used for holding bombs. On the end of the cylinder is a small pinwheel, which, revolved by the rush of air as the released cylinder hurtles downward, ignites the illuminating charge and at the same time detonates a small black-powder charge sufficient to eject the flare and its tightly rolled parachute from the case. The parachute immediately opens and the burning flare descends very slowly, illuminating a large area of territory underneath almost as brightly as though it were day. These flares were used particularly for night-bombing raids, the pilots thus being enabled to illuminate the objectives so that they could accurately drop their bombs. On several occasions, when raiding airplanes were met by heavy fire from the enemy’s antiaircraft batteries, it was found that the light from these flares was so dazzling as to make it impossible for the gunners to take accurate aim. So wide is the radius illuminated by these flares, and so intense their light, that it has been found possible by their aid to obtain aero photographs of excellent detail even on the darkest nights. I can personally vouch for the amazing brilliancy of these flares, for I saw one dropped by the Germans during one of their air-raids on Paris in the summer of 1918. It apparently landed on the Pont Alexandre III or in the Seine, yet both banks of the river, the façades of the Grand and the Petit Palais, and the Champ Elysées for several blocks in both directions were almost as bright as though illuminated by a midday sun. Standing alone in the Cours de la Reine, I had the feeling that the Kaiser’s eye was on me and that, having discovered me, he intended to drop upon me one of his steel visiting-cards. The brilliancy and unexpectedness of the glare reminded me of boyhood days in the Thousand Islands, when the captain of the _Island Wanderer_, making his nightly excursions amid the clustered, cottage-dotted isles, took keen delight in suddenly turning the beam of his powerful search-light upon some affectionate pair love-making on the shore.

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It has been said that the airplane is the eye of the army, and it is equally true that the camera is the eye of the airplane. Nothing more strikingly emphasizes the enormous importance attached to pictures taken from the air, showing the progress of the operations, than the fact that, during the offensive in the Argonne, the American photographic sections made _one hundred thousand aero photographs of the battle-lines in four days_.

As aerial photography was an entirely new military subject at the outbreak of the war in 1914, there were no precedents to act as guides, nor was there any special apparatus in existence. Consequently, the entire art of aerial photography was developed and brought to its present state of perfection by the Allies under the incentive of military necessity and after the war had begun. As trench warfare made aerial photography not only important but vital to the success of any proposed operations, the changes and improvements in the apparatus employed came with incredible rapidity, practices employed one week becoming obsolete the next. By April, 1917, the British Air Service alone had issued approximately 280,000 prints, and this number was equalled, if not surpassed, by the French _Section Photographique_. At the beginning of the war it was possible to fly at low altitudes and secure reasonably satisfactory pictures with such cameras, plates, and lenses as were then available. But as antiaircraft artillery was developed, the planes were forced to climb higher to keep out of their range, and owing to the necessity for longer-focus lenses, special plates, and color filters to overcome the haze existing between the camera and the earth, photography at these high altitudes became increasingly difficult.

When the United States entered the war the British, French, and Italians were using plates exclusively and we followed their lead, it not being until some months later that we turned to films. At this time the British were using 4 × 5 plates, and cameras equipped with lenses of from 8 to 12 inch focus. Instead of making contact prints from these negatives, enlargements 6½ × 8½ were made on glossy paper, it being claimed that this process gave greater control in printing. Whether the British system really had all the advantages claimed for it is open to question, but in any event we adopted it and followed it through the first nine months of the war. The great masters of photography in Rochester were by no means content to let another nation set the pace for the United States, however, and in January, 1918, a concern in that city completed a very remarkable aero camera, radically different from anything which had been seen in Europe up to that time, which was promptly adopted by the War Department. This camera, which took an 18-cm. by 24-cm. picture, had a focal length of 20 inches, held a roll of film on which 100 successive exposures could be made, and weighed only 35 pounds. Its most novel feature was the “vacuum back,” consisting of a perforated sheet which extended across the top of the chamber and over the face of which the film passed. A slight air-suction, produced by a Venturi tube placed where it would catch the rush of air past the plane, served to hold the film absolutely flat—for the slightest curvature of its surface would play havoc with the perspective of a picture taken from a height, say, of 10,000 feet. This ingenious instrument was driven by an electric motor which changed the film and automatically set the shutter, the observer having only to start the machinery going and regulate its speed according to the rate of travel of the airplane in order to obtain a series of pictures forming a continuous photograph of the territory over which the machine was passing.

Another picturesque phase of aerial photography of which the public was permitted to know next to nothing was the so-called “gun camera,” the invention of Thornton Pickard, of Altringham, England. This camera, which was designed for the purpose of training aerial gunners, imitated as closely as possible a Marlin aircraft machine-gun, and in order to make a picture it was necessary for the operator to go through the same movements as in firing a Marlin gun. The picture was made through a circular graticule synchronized with the sight on the fixed machine-gun, so if the film, upon being developed, showed that the gunner had scored a “hit” with the camera, he would have been equally successful with an actual machine-gun. The gun cameras as developed in the United States were of two kinds: one, using a regular Brownie film, took one picture each time the trigger was pulled; the other, which was virtually a motion-picture camera so constructed as to exactly replace the magazine on a Lewis gun, gave a “burst” of exposure with a rapidity equalling that of a machine-gun firing a burst of shots, and was used for training aviators in the handling of their flexibly mounted Lewis guns. The resulting film, or bromide print, consisted of a string of silhouettes of the supposed enemy plane, each with an image of the gun-sights superimposed to show where the gun was held, with reference to the target, at the instant the picture was taken.

The enormous numbers of pictures taken from the skies necessitated a corresponding development and manufacture of travelling dark rooms, seventy-five complete units of these machines being built and shipped overseas. These consisted of mobile photo laboratories, having all the equipment necessary for the rapid production of prints in the field, for when important operations are in progress it is imperative that the aero photographs reach the staff at the earliest possible moment after they are taken. The dark rooms, which were mounted on trucks, were equipped with apparatus for generating the current used in the lamps and enlargers, while trailers were fitted with sinks, tanks, enlarging cameras, and other necessary photographic apparatus. The fact should not be overlooked, moreover, that provision had to be made for training the vast and for the most part inexperienced personnel of the photographic sections in the countless new and peculiar phases of taking pictures from the skies.

In considering the development of military aeronautics it must be borne in mind that the maximum altitudes attained by airplanes increased enormously during the war. In 1914 the record for altitude was 26,246 feet, or slightly less than five miles. By January, 1919, the record had been raised to 30,500 feet, an increase of more than four-fifths of a mile. In 1915 the Western Front pilots worked at 7,000 feet without fear of attack from the ground, and few machines flew at heights of more than 10,000 feet. In fact, the “ceiling” with the early equipment was about 12,000 feet. In the closing months of the war, however, as a result of the development of the antiaircraft artillery, it became necessary for aviators to climb to 15,000 feet over the enemy lines, and tactics of the air made that machine safest which could fly highest.

Now it may not have occurred to you that the higher you ascend the greater becomes the decrease in atmospheric pressure. At 19,000 feet the pressure of the atmosphere is one-half the pressure at sea-level. That means that a given amount of air in the lungs of an aviator flying at that height gives only half the oxygen that it would were he on the ground. It is, then, the lack of oxygen, and not, as many suppose, the low pressure itself, which makes men weak and slow of action at high altitudes. Though these facts have been determined by medical research, it is a curious phase of the flyer’s psychology that most aviators laugh at the idea. Yet any one who has crossed the Rockies or ascended one of the Alpine peaks by funicular has noticed that as the altitude increases the breathing becomes quicker and deeper, the heart beats faster and faster. But though the pilot may, as he asserts, continue to feel perfectly fit and well, he is not as efficient as when near the ground. His reactions become slower, he is less prompt to judge distances, to aim his guns, to fire, to manœuvre his plane—and this despite the fact that he is usually quite unconscious of any impairment of his faculties. He will feel dizzy but perfectly happy—autointoxication, I believe the doctors call it—whereas, as a matter of fact, he has lost his judgment; and if he attempts to stay at these altitudes he will gradually pass into a condition of partial and sometimes total unconsciousness, lose control of his machine, and come crashing to the earth.

The imperative necessity of maintaining flyers at the highest possible efficiency was brought home to the aviation authorities through studying the reports of English air-casualties during the first year of the war. The records divided these as follows: 2 per cent were due to the enemy, 8 per cent were due to the plane, and 90 per cent were due to the men, which clearly indicated that something was radically wrong with the personnel and that prompt action was necessary. A thorough study of the situation disclosed the fact that practically all of the flying personnel was suffering from what is known to scientists as oxygen fatigue, caused by flying for many hours a day at high altitudes where there was not enough oxygen to feed the body. As a result of this discovery, Lieutenant-Colonel Dreyer, of the Royal Army Medical Corps, designed an oxygen apparatus for use by the British air forces, the manufacture of which was immediately begun in Paris. So pressing was the need for these apparatus that an automobile was kept waiting at the plant where they were being manufactured to rush each one to the front as soon as it was finished.

An original model of this apparatus was brought to the United States shortly after we entered the war, but as it was made entirely by hand, it had to be redesigned to meet our manufacturing conditions. The perfected oxygen equipment, as used in the American Air Service, consists of a small tank, or tanks, according to the amount of oxygen carried, a pressure device, a face-mask covering the mouth and nose, and a tube connecting the mask with the oxygen reservoir. The American mask has combined with it the interphone whereby the pilot and observer can converse with each other while in the air and, in certain cases, the receiver of the radio telephone. In May, 1918, six complete apparatus were sent overseas by special messenger to be tried out under battle conditions, and when the war ended 5,000 had been manufactured and accepted. All American military planes flying at an altitude of over 10,000 feet are now fitted for the installation of oxygen equipment. This includes day-bombing, pursuit, and chase planes, and a percentage of night-bombing and observation machines. So much importance was attached by the military authorities to supplying our flying-men with oxygen that a special oxygen division was organized and sent to France for the purpose of installing the apparatus in the planes. Yet, as I have previously remarked, the flyers themselves persist in regarding the apparatus, probably because of the discomfort involved in wearing it, with amused scepticism.

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Of all the inventions which have sprung from the war, none is more amazing, to my way of thinking, than the radio telephone. Think of standing on the ground and holding a conversation in a normal tone of voice with an aviator so high in the sky that you cannot see his airplane with the naked eye. Think of it! Before we entered the war, any one save a handful of enthusiastic scientists would have ridiculed such a suggestion, yet to-day, at any one of a score of flying-fields, you can sit at an office desk and converse with aviators in the clouds as easily as though you were sitting opposite them at a dinner-table.

The pilot and observer are able to talk to each other through the same instrument by means of which they communicate with the ground.

_Photograph by Signal Corps, U. S. A._]

_Photograph by Signal Corps, U. S. A._]

One of the most remarkable inventions of the war. This instrument not only ascertains the altitude and position of an airplane but by means of an electric connection automatically sets the sights on the antiaircraft gun.]

The enormous advantage which such an invention would give to the army possessing it was early recognized by certain electrical engineers and a few scientifically minded officers of the Signal Corps, and, as a result of their enthusiasm, before the first contingent sailed for France work had been begun on the development of a radiotelephone set for airplanes. There is no necessity of recounting the innumerable experiments and heart-breaking failures before the first real successes were obtained. So far as the radio part of the problem was concerned, a solution was had in a comparatively short time. But working this apparatus in a swift-moving and terrifically noisy airplane was quite a different matter, it was quickly discovered, from working it under ordinary conditions on the ground, the roar of the engine and the rushing air making it impossible to hear one’s own voice, much less the weak signals of the receiver. One of the first problems to be solved, therefore, was to design a head-set which would exclude these noises while at the same time permitting the voice of the telephone to be heard. The answer was found in a form of aviator’s helmet fitting the head so closely as to exclude virtually all extraneous sounds save those coming through telephone-receivers inserted in the helmet so as to fit the ears. No sooner was this problem solved, however, than another one demanded solution. A means had been devised for protecting the receivers from outside noises—but how about the _transmitter_? Every one knows how sensitive the ordinary telephone-transmitter is to extraneous sounds, so it does not require much imagination to picture how impossible it would be for the aviator to make his voice heard in a transmitter alongside a 200 horse-power airplane engine. But a brilliant series of experiments, conducted largely by Mr. J. P. Minton, of the Western Electric Company, resulted in a form of telephone-transmitter or microphone which possessed the remarkable quality of being insensible to engine and wind noises and at the same time highly responsive to the tones of the voice. With these two elements in hand it was thought that the problem was solved, but three more months of unremitting work were required to perfect the apparatus to a state where it was practicable for use by others than experts. At last everything was ready, however, and in December, 1917, the officials of the Aircraft Production Board and the joint Army and Navy Technical Boards announced that they would witness an exhibition of the apparatus at the Moraine Flying-Field at Dayton. Two days before the date set for the demonstration a group of the engineers and mechanics who had been working over the problem almost night and day during the preceding six months descended, with many cases of paraphernalia, on the Ohio town. Only the enthusiasts who for the preceding half-year had spent their days working over the problem and their nights dreaming of it believed that the exhibition would prove successful. Every one else was sceptical. The plan was to have two planes, both carrying radio sets, in the air at the same time, while the visiting officials listened in at a ground-station located on the top of a near-by hill. That night the inventors and their assistants congregated in a room of the hotel where they were staying and worked out a scenario and held a rehearsal of the morrow’s programme. A famous electrical expert represented one plane and a young engineer represented the other, while the inventors, sitting in the middle of the room, gave them their orders and sent them sailing over beds, chairs, and tables as it was hoped their planes would manœuvre in the clouds the next day. No one slept very well that night. The morning was cold and dismal, in keeping with the spirits of all concerned. Upon the arrival of the exalted ones, among whom were several of the foremost scientists and inventors of America, they were shown the apparatus installed in the two planes and were told what it was expected to do. They were then escorted up to the little station on the hill, where a loud-speaking receiver had been connected with the wireless apparatus, so that all could hear without the use of head-sets. The planes left the ground, and after what seemed an interminable length of time, there came from the receiver the first faint sounds which indicated that they were ready to perform. The officials, with their coat-collars about their ears, appeared only mildly interested and several gave unmistakable signs of being bored. Suddenly, without the slightest warning, out of the horn of the loud-speaker came the words: “_Hello, ground-station! This is Plane Number One speaking. Do you get me all right?_” The bored expressions on the faces of the officials changed to expressions of amazement tinged with awe. Instead of the confusing dash-dot-dash which they associated with wireless, here was a human voice coming out of space clear and distinct—yet the speaker was two miles in the air. Soon the same signal came from the other plane and the exhibition was on. Under command from the ground the planes were manœuvred all over that part of the country. They climbed and volplaned and circled. They were sent on scouting expeditions and reported what they saw as they travelled through the air. Continuous conversation was carried on, even when the planes were out of sight, and finally, upon command, they came tearing down the skies like two huge homing pigeons and landed where directed. From that moment the radio telephone was sold to the government. It was no longer a question as to whether it would work, but how soon and in what quantity its manufacture could be started.

The primary object of the airplane telephone is to make it possible for the commander of an air-squadron to control the movement of his men in the air just as a drill-sergeant directs the evolutions of a platoon on the ground. For this purpose extra-long range is not required or, indeed, desired, the distance over which they can talk being purposely limited to two or three miles, so that the enemy cannot overhear except when actually engaged in combat. Then it does not matter.

Neither my space nor my knowledge of electrical engineering are sufficient to permit of explaining in detail the working of the radio telephone. It is enough to say that a wind-driven generator supplies electric current to a couple of vacuum tubes mounted in a box filled with coils and condensers. These tubes transform the dynamo current into a high-frequency alternating current which is fed out into space through the antenna. This antenna consists of a copper wire about 200 feet long, which with a lead weight on the end trails out behind the airplane when it is in flight. Normally this wire is wound up on a reel, being let out and wound in as occasion demands. With the special form of telephone-transmitter already described, the words of the aviator are impressed on this wire, the electric waves thus set in motion radiating out into space, where they are picked up by similar antennæ either on other planes or on masts on the ground. The receiving process is the exact reverse of that used in sending, other vacuum tubes taking the high-frequency current from the antenna and transforming it so that it can be heard in the form of speech in the telephone fitted in the aviator’s helmet or in the loud-speaking horn on the ground. That is about as near as I can come to explaining the radio telephone without writing a book.

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One of boyhood’s most joyous recollections is that of “balloon day” at the county fair, when the great yellow spheroid in the middle of the race-track enclosure slowly filled (oh, so slowly, it seemed!), bulged, tugged at its moorings, and at last rose majestically skyward, the aeronaut, a lithe figure in spangled tights, waving down to the sea of upturned faces as he swung at ease in his cobweb-like trapeze. But, though the recollection of the balloonist’s skill and daring remains sharp and clear in our minds, so much space has been devoted in the war books and the news despatches to the exploits of the aviators that we seem to have completely lost sight of the no less hazardous work of those daring souls who, day after day, in heat and cold, in snow and drenching rain, sat huddled in their frail baskets under the swaying gas-bags, often a mile above the ground, and through their glasses watched what the enemy was doing, heedless of the repeated attempts made by the enemy’s gunners and flyers to bring them down. Though they have received practically no share of the publicity and praise which has been showered upon the flying-men, the officers and men of the Balloon Section of the Air Service deserve from the public its deepest gratitude and appreciation. The perilous nature of their work is shown by the fact that in the last six weeks of the war twenty-one American balloons were lost, six being destroyed by shell-fire and fifteen by enemy planes. Its importance is emphasized by the fact that the Germans gave official credit to their aviators of _one and a half planes for every balloon brought down_.

Those daring souls who day after day sat huddled in their frail baskets and through their glasses watched what the enemy was doing.]

_Photograph by U. S. Air Service._]

At the beginning of the war the artillery-fire of the Allies was directed for the most part by airplanes. Their work, however, left much to be desired. Though the plane observers could locate targets fairly well, they frequently lost touch with their batteries through the difficulty of sending and receiving wireless or visual signals from the swiftly moving craft. Thus there came into use the captive balloon, which by the end of the war had practically replaced the airplane as a director of gun-fire wherever possible, thus making the artillery infinitely more efficient than ever before. Sitting comfortably aloft, the observer in the basket of a kite-balloon had the whole panorama of his particular station spread beneath him like a map in bas-relief, being able to detect, with the aid of powerful glasses, anything transpiring within a radius of ten miles or more. He was constantly in touch with his batteries by telephone and could not only give the gunners, by means of co-ordinated maps, the exact location of their target and the effect of their bursting shells, but could keep the staff informed of enemy troop movements, airplane activities, and preparations for impending attacks. The balloonist became, indeed, a veritable sentinel of the skies, hovering over the battle-lines with the persistency and the keen, long-range vision of a hawk. He played a less spectacular part in the great drama than the airplane scout or fighter in the latter’s free and dazzling flights, but his duties were scarcely less important. Nor did he suffer from ennui during his stays aloft. When a kite-balloon went up along the battle-front it at once became the subject of the keenest attention by the enemy because it was known to be up on business and was certain to be the cause of damage unless it was forced down. Long-range, high-velocity guns were trained on it and, from the upper levels of the air, planes came swooping down upon it in their attempts to dash through the screen of shells from the antiaircraft guns and put an incendiary bullet into the sausage-shaped, elephant-colored gas-bag which so insolently defied them. And a bullet which got home meant the instant ignition of the highly inflammable hydrogen, the quick destruction of the balloon and, perhaps, the occupants of the basket as well, unless they could get away in their parachute. From the moment the gas leaped into flame until the fall of the balloon was rarely over fifteen or twenty seconds, so quick thinking and quick work was called for if the men in the basket were to jump to safety. The pilot of the airplane could dodge and swerve and slip away from the guns by a hundred shrewd devices; not so the pilot of the kite-balloon anchored to its windlass. He had to carry on his abstruse mathematical calculations unconcernedly, his spare moments being enlivened by watching the flash of an enemy gun on a distant hill and then waiting twenty or thirty seconds for the whining messenger of death to reach him, pondering, meanwhile, on the accuracy of that particular gunner. As a matter of fact, few direct shell-hits on a balloon were recorded during the war, most of the balloons which were brought down having been accounted for by incendiary bullets from diving planes. Just as some sportsmen devote their energies to moose and elk and grizzlies while others specialize on smaller game, so some of the airplane pilots made a specialty of hunting “sausages,” and at this thrilling and highly perilous sport became amazingly expert. When the Crown Prince’s assaults on Verdun were at their height, I saw eight French aviators start out to bring down eight German balloons. Within less than thirty minutes seven of the _drachen_ had come down in flames—which shows that a balloonist was not a good life-insurance risk. The average life of an observation balloon on the Western Front was estimated to be about fifteen days. Sometimes it lasted only a few minutes. There is a record of an American balloon passing unscathed through the whole period of American activity on a busy sector, but it was generally considered that a balloon which has seen five or six months of ordinary non-war service has done its duty and is unsafe because of the deterioration of the fabric.

In August, 1914, Germany had perhaps a hundred kite or “sausage” balloons, France and England a very few. The German type was known as the “Drachen,” and consisted of a gas-cylinder of rubberized cloth about sixty-five feet long and twenty-seven feet in diameter, with hemispherical ends. For stability a lobe, about a third of the diameter of the cylinder, was attached to the underbody of the gas-bag and curved up around the end. This lobe, made of a lighter fabric than the bag itself, automatically filled with air as the balloon ascended and acted as a rudder to hold the balloon in line. For further stability three tail-cups, one behind the other, with mouths open to the wind, were attached to the rear of the balloon.

While the Drachen balloon was a rather clumsy affair and proved unstable in high winds, its importance as an adjunct to the artillery was early recognized by the Allies, for the results of its work daily became more apparent. Though the armies of France, England, Italy, and the United States made repeated experiments in an attempt to evolve a type which should possess greater stability and permit of higher altitudes being attained, it remained for Captain Caquot, of the French Army, to produce a balloon which possessed both of these qualities, his name now being used as a designation for the type which he invented and which was in general used by the Allied armies during the last year of the war. The Caquot received its greatest compliment from Germany when her army adopted this type of balloon and discarded the Drachen.

The Caquot is an elongated gas-bag, ninety-three feet long and twenty-eight feet in its widest diameter, made of rubberized cotton cloth and sharply streamlined. Hydrogen gas is the ascensive power used, lifting the cable, two men, basket, and all other equipment to a maximum altitude, in the best weather conditions, of over 5,000 feet. It has a balloonet, or air-chamber, within the main body of the gas-envelope, which as the balloon ascends fills automatically with air through a simple scoop placed under the nose of the balloon. The air and gas chambers are separated by a diaphragm of cloth. When the balloon is fully inflated this diaphragm rests on the underbody of the gas-envelope, there being no air in the balloonet. When the balloon descends, minus the several hundred feet of hydrogen which has escaped into the air, it would lose its shape and grow flabby, a condition of considerable potential danger, were it not for the balloonet, or air-chamber, coming into play. As the air is driven in through the scoop, precisely as an air-scoop fixed in the port-hole of an ocean liner brings air into a cabin, the diaphragm rises and takes up the lost bulk in the gas-envelope above. In other words, the escaping gas is replaced by air by means of what amounts to an elastic air-envelope below the gas-envelope. Is that quite clear? Three lobes of rubberized fabric give stability to the balloon. They are filled automatically by the wind, if it blows, and, expanding to their full capacity, act as rudders to hold the balloon steady. If there is no wind there is, of course, no need for the lobes and they hang loosely, like elephants’ ears, Caquots frequently being called “elephants” because of these drooping lobes.

The lobes of rubberized fabric give stability to the balloon. They are filled automatically by the wind, if it blows, and, expanding to their full capacity, act as rudders to hold the balloon steady.]

As accurately spaced as the pips on a card; as picturesque as a flock of geese southwardly bound.]

When the United States entered the war we were practically without this type of aircraft, the only balloon possessed by our military forces on the Mexican border having been the gift of an Akron rubber company to the Ohio National Guard. In April, 1917, the whole production of military balloons in the United States was not over two or three a month, but at the request of the government the various rubber manufacturers went whole-heartedly into the business of production, so that when the war ended we were producing ten balloons a day. Up to November 11 there had been produced for the United States Army alone 1,025 balloons of all types, 642 of these being the final Type R Observation Balloon. Propaganda and target balloons were likewise developed and produced, as were new-type parachutes, canvas balloon hangars, and 1,221,582 feet of steel cable—a sufficient length of single-strand, specially manufactured wire to more than reach around the globe.

One of the chief difficulties which had to be overcome was the question of a sufficient supply of cotton cloth of proper strength and texture, for balloon cloth was practically unknown in this country when we entered the war. In order to keep up with the balloon schedule of the War Department, the manufacturers required millions of yards of a very high-grade cloth with a weave of 140 threads to the inch both ways. At first the wastage due to imperfect balloon cloth was enormous, frequently running as high as 60 per cent, but by care and effort this was reduced to perhaps 10 per cent in total from the loom to the balloon. The wastage was largely caused by “slubs,” knots, and other imperfections of weaving, which prevented an even surface for rubberizing and consequently impaired the strength and gas-holding qualities of the cloth. Hundreds of inspectors, both factory and government employees, were necessary to get an approximately perfect fabric, and all had to be developed for this work. Indeed, the making of balloon cloth in the United States amounted to the development of an entirely new industry, for which thousands of men had to be specially trained for months. It will give you a better conception of the magnitude of this new industry, perhaps, when I tell you that to make ten balloons a day it was necessary for the cotton-mills to weave about 600,000 yards of this special balloon cloth a month, and this required 3,200 looms. It is a tribute to the skill of the American weavers that reports from the front stated that the American fabric burnt very much more slowly than that made in Europe, thus giving the observer more time to get away in his parachute and minimizing the danger of the burning balloon falling on him.

Everything connected with the kite-balloon presented more or less of a problem because it was new. The mobile windlass, for example, by which the balloon was let up and pulled down on its cable, had to be developed from nothing. But the genius of the American manufacturer overcame this difficulty as it did every other in the manufacture of instruments for war. Though steam was the motive power first used for balloon windlasses, before the close of the war American ingenuity had developed both gas and electric windlasses which were thoroughly efficient. The mobile windlass could move on the road under its own power at a speed of twenty miles an hour, and could tow a balloon in the air at the rate of five miles an hour, or even better if necessity demanded. The gasoline windlass has made a record pull-down of 1,600 feet a minute, bringing down its balloon at a speed more than _three times that of the fastest passenger-elevator_.

A sufficient supply of hydrogen gas was, at the beginning, another of the balloon problems. Hydrogen, before the war, was a by-product in the manufacture of commercial oxygen, and only a small quantity was used in this country. But the sudden demand for millions of cubic feet of this gas was promptly met by the establishment of government plants and the expansion of privately owned ones. Though by far the greater part of the gas used in balloons at home and abroad was made at permanent supply stations and shipped to the points where it was needed, in steel cylinders, an extremely ingenious type of portable generator was developed for the manufacture of hydrogen in the field. When these portable hydrogen generators were unnecessary or unavailable, the gas shipped from long distances was stored in high-pressure cylinders or “nurse balloons,” the latter being simply huge bags of rubberized fabric, each with a capacity of 5,000 cubic feet of hydrogen, which were used in the same way as the ordinary steel gasometers to be seen in any American city.

Hydrogen is itself an inflammable gas, and when mixed with air or oxygen is dangerously explosive. It has, therefore, always been a source of great concern to balloonists, who had long dreamed of a non-inflammable, non-explosive gas, sufficiently light to function as does hydrogen. It was known that helium was such a gas, but it was, until very recently, so scarce and costly that its use in balloons had scarcely been given a serious thought. Not more than 100 cubic feet of helium had ever been produced up to the time we started our balloon programme, and it was valued at $1,700 a cubic foot. Scientific investigators in the employ of the government discovered about this time, however, that certain natural gases in the United States contained limited quantities of helium, and the problem then resolved itself into one of extracting the helium from these gases in sufficient quantities, and at a sufficiently low cost, to make practical its use. Funds were forthcoming and, under the supervision of the Navy Department and the Bureau of Mines, the process of gas liquefaction was put into operation, with the result that on the day of the Armistice there were on the docks, ready for shipment overseas, 147,000 cubic feet of helium with a pre-war value of a quarter of a billion dollars. Plants were under construction which, had the war continued, would have produced 50,000 cubic feet of this gas a day at a cost of approximately ten cents per cubic foot. The importance of this discovery cannot be overestimated, for it marks the opening of a new era in lighter-than-airship navigation. In war it will make the incendiary bullet, which has caused the destruction of countless balloons, a joke. The only way to bring down a balloon filled with helium will be literally to tear it apart by a direct hit with a high-explosive shell. Under peace conditions, it opens up undreamed-of possibilities in the development of new types of dirigible airships, as the danger from lightning, static electricity, and sparks of any kind has been entirely eliminated. To cross the Atlantic in a helium-filled balloon will be safer, so far as danger from fire is concerned, than to cross the continent in a train.

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Do you remember that hot September afternoon at the county fair when you sat perched on the white-washed race-track fence, your face turned skyward, and watched with fascinated eyes the tiny yellow globule, high, high in the blue, which you had seen rise from the ground half an hour before as a giant gas-balloon? And do you remember how, as you watched, the band in the grand stand suddenly stopped playing and an awed hush fell upon the crowd, and you saw a tiny something detach itself from the yellow globule and drop into space, at first falling with sickening speed, then slower, still slower, until the object, which you knew was a man in pink tights (though sometimes, in order to heighten the sensation, it was a young and, of course, beautiful woman), landed quite gently in a distant field? In those days we little dreamed that the strange, umbrella-like contrivance which brought the aeronaut safely to earth would ever be used for any other purpose than to thrill the admission-paying multitudes, but the emergencies and necessities provoked by the Great War turned things with which we were all familiar to unfamiliar uses, as, for example, when it converted a farm tractor into a fighting-tank. Thus it was that the observers came to use parachutes to escape from their burning balloons just as the inmates of an office-building dash down the iron fire-escapes when somebody shouts “Fire!”

At first the individual or one-man parachute was used to insure the escape of the observer in the basket from his burning balloon, but though the man escaped, the valuable maps and records were lost. In order to save these records there was invented the basket parachute. This was considerably larger in diameter than the individual parachute, and when cut away brought the basket with all that it contained—men, records, instruments, everything—safely and quickly to the ground. All the observer had to do was to pull a cord and he started downward. It was easier than stepping into an elevator and saying: “Ground floor, please.” Amazingly few fatalities occurred in the hundreds of cases in which the individual and basket parachutes were used in actual war service or in training. I heard of one balloon observer who was forced to make four parachute jumps in a single day, and of another who made three in four hours, two balloons being burned over his head. Thirty parachute jumps were made by American observers during the Argonne offensive alone. Yet the safety of the parachute is demonstrated beyond all question by the fact that during the entire time the American forces were in the field only one death occurred as the direct result of a parachute drop, and in that particular instance the burning balloon fell directly on top of the open parachute, setting it on fire and allowing the observer to fall the rest of the distance to the earth.

The basket parachute brings men, instrument, and records safely to the ground.]

“By means of a machine known as the Ruggles ‘Orientator,’ he could, while on the ground, be put through every possible evolution experienced in actual flying.”]

It is interesting to note that the use of parachutes is relatively new compared even with ballooning. The man who developed the parachute and who first descended safely to earth by its means—Thomas S. Baldwin—now holds a major’s commission in the American Air Service, and during the war had direct charge of the inspection of all army balloons and parachutes. As the result of a life spent in performing aerial exploits of all kinds, under all conditions and in all parts of the world, Major Baldwin knows what is and what is not safe, so that when a balloon or parachute was sent into action the observer always had the satisfaction of knowing that the world’s most famous balloonist had given it his O. K.

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Speaking of parachute jumps reminds me of an incident which actually occurred on one of the American sectors toward the close of the war. Despite the fact that only one American balloonist lost his life in making a parachute jump—and in that case the fatality was caused by the burning balloon falling on and setting fire to the parachute—a very considerable element of risk is involved in the performance. In fact, it became the custom to recommend a man making a parachute jump for the Distinguished Service Cross, or, if he was operating with the French, for the Croix de Guerre.

Just before the opening of the Argonne offensive an observation balloon over the American lines was attacked by a German plane and sent down in flames, the observer escaping by means of his parachute.

“You’ll get the D. S. C. all right,” his friends greeted him, as he disentangled himself from the parachute harness.

“We’re sending up another balloon in a few minutes,” said the commanding officer. “Want to try it again?”

“Surest thing you know, sir,” replied the grinning youngster.

But before the second balloon had been in the air an hour another enemy plane swooped down upon it, like a hawk on a chicken-yard, and it too burst into flame. Again the observer floated to safety beneath his parachute.

“I guess I’ve got that D. S. C. copper-riveted this time,” he remarked; but, when a third balloon ascended, he was in the basket. Once more a German plane came tearing down the skies, a stream of bullets ripped the silken gas-bag, and for the third time that day the observer reached the earth by the parachute route.

“You’ll probably get the Croix de Guerre as well as the D. S. C.,” his friends assured him. “The French are strong for this sort of thing. They may even give you the Legion of Honor.”

Treading on air, the youngster returned to balloon headquarters. Tacked on the bulletin-board in the hallway was a General Order. He paused to glance at it. This is what he read:

“It is hereby directed that the custom of recommending officers making parachute jumps for the Distinguished Service Cross or other decorations be discontinued.”

Though the question of providing proper clothing for our flying-men and balloon observers did not loom large when compared with the vast problems involved in the production of engines, spruce, balloon cloth, bombs, and machine-guns, it was nevertheless an exceedingly important one, for an aviator cannot do his work if he is cold, and it is always bitterly cold in the higher air-lanes. A man flying at 20,000 feet, say, suffers more from the cold than he would on the ice-fields at the North Pole. Aviators are commissioned officers, and when not at work wear the regular uniform, which, as in the case of all officers, is furnished by the officer himself. But the clothing required for work in the air, being of a highly special character and very expensive, is loaned to the flyers by the government. In view of this, it is a source of satisfaction to know that it was frankly admitted on the front that our flyers were by far the best and most efficiently equipped of any nation.

After many tests and much development, the following outfit was devised: On the head was worn, in moderate weather, first a woollen hood, or helmet, so designed as to fit closely over the entire head and shoulders. In extremely cold weather, or for high-flight work, there was worn a silk hood of like design and double thickness, having between its layers an electrically heated unit connected by copper-wire cables extending through the suit proper with the generator on the engine of the plane. Over this silk hood was worn a soft-leather helmet lined with fur, the face was entirely covered with a wool-lined leather mask, and the eyes were protected by goggles. When it was necessary for the aviator to use the radiotelephone, however, the fur-lined helmet was replaced by the radio helmet, a leather affair somewhat similar in design to the other but so fashioned as to contain the receivers of a wireless telephone. For high-flight work, in addition to the above equipment, a rubber oxygen mask, which contained a transmitter permitting the wearer to speak as well as hear by wireless, was also worn. This mask was attached by a flexible tube to a tank of oxygen carried in the plane, being so arranged that it automatically fed the aviator with the amount of oxygen required for the altitude at which he was flying.

Over the body was worn a one-piece flying suit of waterproof, airproof material, reaching from throat to feet, buttoned tightly at wrists and ankles, and lined throughout with fur. Through these suits, between the fur and the outer coverings, were placed wire cables terminating in snap-fasteners at neck, wrists, and ankles, to which could be attached silk-covered wires leading to other electrical heating units in the helmets, gloves, and moccasins, all of which were warmed by a current drawn from the generator on the engine. Hence, though our aviators not infrequently flew in a temperature of thirty degrees below zero, they were as warm and comfortable as though they were sitting before a log fire at home—much more comfortable, in fact, than were their relatives and friends in America on the fireless Sundays which made uncomfortable the first winter of the war. On his hands the aviator wore, in addition to the electrically heated gloves, a pair of muskrat gauntlets extending nearly to the elbow; on his feet, over the electrically heated moccasins, another pair of moccasins, lined with sheepswool, reaching almost to the knees. It is scarcely necessary to add that our air-fighters spent more time in dressing than does a chorus-girl in a comic opera, and that when they were dressed they looked like a cross between an Arctic explorer and a deep-sea diver.

The question of obtaining the fur for lining this clothing presented a perplexing problem, for there were required vast quantities of pelts or skins of extreme warmth and sufficiently strong to withstand rough usage, but not too bulky or heavy. After considerable investigation it was found that these requirements were met by the skin of the Nuchwang dog, which inhabits one of the provinces of north China, though I have no doubt that sable or ermine would have answered the purpose equally well had cost been no consideration. The demands of the American Air Service required practically all of these skins that could be had in China and necessitated the lifting of an embargo to bring them into the United States, which, thanks to the co-operation of the War Trade Board, was obtained. The last purchase before the Armistice was signed called for 500,000 of these dog-skins. A strange thing, was it not, that the lust for power of one William Hohenzollern, late of Berlin and Potsdam, should bring about, among countless other things, the slaughter of half a million dogs in far-off China? Though figures are, as a rule, dry things, the magnitude of the Air Service’s clothing problem can be better appreciated by my giving a few of them. The work in hand for air-clothing when the Armistice was signed involved upward of $5,000,000. Fifty thousand fur-lined flying suits at $36.25; over a 100,000 leather helmets at $4.50; a like number of leather coats at prices ranging from $10 to $30, and 80,000 goggles at $3.50 a pair reflect the major items and explain how the government spent some of the money which you paid for your Liberty Bonds.

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Though in this chapter I have attempted to sketch the manifold phases of America’s preparation for obtaining supremacy in the sky, I have purposely left until the last the most important phase of all—the flying-men themselves. The personnel side of the Air Service, including the selection, training, organization, and operation of the flying forces, developed, within the year following America’s declaration of war, into one of the most remarkable educational systems in this or any other country, with a larger student body and a more diverse curriculum than any university in the world. Teaching men to fly, to send messages by wireless, to operate machine-guns in the air, to gauge the effectiveness of artillery-fire by its bursts, to read and make maps, to operate gas-engines, and to travel hundreds of miles by compass; teaching other men to read the enemy’s strategy from aerial photographs, and still others to repair instruments, ignition systems, propellers, airplane wings, and motors, required a vast network of schools and flying-fields, a huge force of instructors, many of whom themselves had to be trained, and an amazing mass of equipment and curricula.