The Dominion of the Air by J. M. BaconThe Story of Aerial Navigation (page 5)

lon. We are at an altitude of 600 metres. All well.–Andree, Svedenborg, Frankel.’ “

Commenting on the first message, Mr. Percival Spencer says:–“I cannot place reliance upon the accuracy of either the date or else the lat. and long. given, as I am confident that the balloon would have travelled a greater distance in two days.” It should be noted that Dane’s Island lies in 79 degrees 30 minutes north lat. and 10 degrees 10 minutes east long.

Mr. Spencer’s opinion, carefully considered and expressed eighteen months afterwards, will be read with real interest:–

“The distance from Dane’s Island to the Pole is about 750 miles, and to Alaska on the other side about 1,500 miles. The course of the balloon, however, was not direct to the Pole, but towards Franz Josef Land (about 600 miles) and to the Siberian coast (another 800 miles). Judging from the description of the wind at the start, and comparing it with my own ballooning experience, I estimate its speed as 40 miles per hour, and it will, therefore, be evident that a distance of 2,000 miles would be covered in 50 hours, that is two days and two hours after the start. I regard all theories as to the balloon being capable of remaining in the air for a month as illusory. No free balloon has ever remained aloft for more than 36 hours, but with the favourable conditions at the northern regions (where the sun does not set and where the temperature remains equable) a balloon might remain in the air for double the length of time which I consider ample for the purpose of Polar exploration.”

A record of the direction of the wind was made after Andree’s departure, and proved that there was a fluctuation in direction from S.W. to N.W., indicating that the voyagers may have been borne across towards Siberia. This, however, can be but surmise. All aeronauts of experience know that it is an exceedingly difficult manoeuvre to keep a trail rope dragging on the ground if it is desirable to prevent contact with the earth on the one hand, or on the other to avoid loss of gas. A slight increase of temperature or drying off of condensed moisture may–indeed, is sure to after a while–lift the rope off the ground, in which case the balloon, rising into upper levels, may be borne away on currents which may be of almost any direction, and of which the observer below may know nothing. As to the actual divergence from the wind’s direction which a trail rope and side sail might be hoped to effect, it may be confidently stated that, notwithstanding some wonderful accounts that have gone abroad, it must not be relied on as commonly amounting to much more than one or, at the most, two points.

Although it is to be feared that trustworthy information as to the ultimate destination of Andree’s balloon may never be gained, yet we may safely state that his ever famous, though regrettable, voyage was the longest in duration ever attained. At the end of 48 hours his vessel would seem to have been still well up and going strong. The only other previous voyage that had in duration of travel approached this record was that made by M. Mallet, in 1892, and maintained for 36 hours. Next we may mention that of M. Herve, in 1886, occupying 24 1/2 hours, which feat, however, was almost equal led by the great Leipzig balloon in 1897, which, with eight people in the car, remained up for 24 1/4 hours, and did not touch earth till 1,032 miles had been traversed.

The fabric of Andree’s balloon may not be considered to have been the best for such an exceptional purpose. Dismissing considerations of cost, goldbeaters’ skin would doubtless have been more suitable. The military balloons at Aldershot are made of this, and one such balloon has been known to remain inflated for three months with very little loss. It is conceivable, therefore, that the chances of the voyagers, whose ultimate safety depended so largely upon the staying power of their aerial vessel, might have been considerably increased.

One other expedient, wholly impracticable, but often seriously discussed, may be briefly referred to, namely, the idea of taking up apparatus for pumping gas into metal receivers as the voyage proceeds, in order to raise or lower a balloon, and in this way to prolong its life. Mr. Wenham has investigated the point with his usual painstaking care, and reduced its absurdity to a simple calculation, which should serve to banish for good such a mere extravagant theory.

Suppose, he says, the gas were compressed to one-twentieth part of its bulk, which would mean a pressure within its receiver of 300 lbs. per square inch, and that each receiver had a capacity of 1 cubic foot, while for safety sake it was made of steel plates one-twentieth of an inch thick, then each receiver would weigh 10 lbs., and to liberate 1,000 feet clearly a weight of 500 lbs. would have to be taken up. Now, when it is considered that 1,000 cubic feet of hydrogen will only lift 72 lbs., the scheme begins to look hope less enough. But when the question of the pumping apparatus, to be worked by hand, is contemplated the difficulties introduced become yet more insuperable. The only feasible suggestion with respect the use of compressed gas is that of taking on board charged cylinders under high pressure, which, after being discharged to supply the leakage of the balloon could, in an uninhabited country, be cast out as ballast last. It will need no pointing out, however, that such an idea would be practically as futile as another which has gravely been recommended, namely, that of heating the gas of the balloon by a Davy lamp, so as to increase its buoyancy at will. Major Baden-Powell has aptly described this as resembling “an attempt to warm a large hall with a small spirit lamp.’

In any future attempt to reach the Pole by balloon it is not unreasonable to suppose that wireless telegraphy will be put in practice to maintain communication with the base. The writer’s personal experience of the possibilities afforded by this mode of communication, yet in its infancy, will be given.

CHAPTER XXV. THE MODERN AIRSHIP–IN SEARCH OF THE LEONIDS.

In the autumn of 1898 the aeronautical world was interested to hear that a young Brazilian, M. Santos Dumont, had completed a somewhat novel dirigible balloon, cylindrical in shape, with conical ends, 83 feet long by 12 feet in diameter, holding 6,500 cubic feet of gas, and having a small compensating balloon of 880 cubic feet capacity. For a net was substituted a simple contrivance, consisting of two side pockets, running the length of the balloon, and containing battens of wood, to which were affixed the suspension cords, bands being also sewn over the upper part of the balloon connecting the two pockets. The most important novelty, however, was the introduction of a small petroleum motor similar to those used for motor tricycles.

The inventor ascended in this balloon, inflated with pure hydrogen, from the Jardin d’Acclimatation, Paris, and circled several times round the large captive balloon in the Gardens, after which, moving towards the Bois de Boulogne, he made several sweeps of 100 yards radius. Then the pump of the compensator caused the engine to stop, and the machine, partially collapsing, fell to the ground. Santos Dumont was somewhat shaken, but announced his intention of making other trials. In this bold and successful attempt there was clear indication of a fresh phase in the construction of the airship, consisting in the happy adoption of the modern type of petroleum motor. Two other hying machines were heard of about this date, one by Professor Giampietre, of Pavia, cigar-shaped, driven by screws, and rigged with masts and sails. The other, which had been constructed and tested in strict privacy, was the invention of a French engineer, M. Ader, and was imagined to imitate the essential structure of a bird. Two steam motors of 20-horse power supplied the power. It was started by being run on the ground on small wheels attached to it, and it was claimed that before a breakdown occurred the machine had actually raised itself into the air.

Of Santos Dumont the world was presently to know more, and the same must be said of another inventor, Dr. Barton, of Beckenham, who shortly completed an airship model carrying aeroplanes and operated by clockwork. In an early experiment this model travelled four miles in twenty-three minutes.

But another airship, a true leviathan, had been growing into stately and graceful proportions on the shores of the Bodenzee in Wurtemberg, and was already on the eve of completion. Count Zeppelin, a lieut.-general in the German Army, who had seen service in the Franco-German War, had for some years devoted his fortune and energy to the practical study of aerial navigation, and had prosecuted experiments on a large scale. Eventually, having formed a company with a large capital, he was enabled to construct an airship which in size has been compared to a British man-of-war. Cigar-shaped, its length was no less than 420 feet, and diameter 40 feet, while its weight amounted to no more than 7,250 lbs. The framework, which for lightness had been made of aluminium, was, with the object of preventing all the gas collecting at one end of its elongated form, subdivided into seventeen compartments, each of these compartments containing a completely fitted gas balloon, made of oiled cotton and marvellously gas tight. A steering apparatus was placed both fore and aft, and at a safe distance below the main structure were fixed, also forward and aft, on aluminium platforms, two Daimler motor engines of 16-horse power, working aluminium propellers of four blades at the rate of 1,000 revolutions a minute. Finally, firmly attached to the inner framework by rods of aluminium, were two cars of the same metal, furnished with buffer springs to break the force of a fall. The trial trip was not made till the summer following–June, 1900–and, in the meanwhile, experiments had gone forward with another mode of flight, terminating, unhappily, in the death of one of the most expert and ingenious of mechanical aeronauts.

Mr. Percy S. Pilcher, now thirty-three years of age, having received his early training in the Navy, retired from the Service to become a civil engineer, and had been for some time a partner in the firm of Wilson and Pilcher. For four or five years he had been experimenting in soaring flight, using a Lilienthal machine, which he improved to suit his own methods. Among these was the device of rising off the ground by being rapidly towed by a line against the wind.

At the end of September he gave an exhibition at Stamford Park before Lord Bray and a select party of friends–this in spite of an unsuitable afternoon of unsteady wind and occasional showers. A long towing line was provided, which, being passed round pulley blocks and dragged by a couple of horses, was capable of being hauled in at high speed. The first trial, though ending in an accident, was eminently satisfactory. The apparatus, running against the wind, had risen some distance, when the line broke, yet the inventor descended slowly and safely with outstretched wings. The next trial also commenced well, with an easy rise to a height of some thirty feet. At that point, however, the tail broke with a snap, and the machine, pitching over, fell a complete wreck. Mr. Pilcher was found insensible, with his thigh broken, and though no other serious injury was apparent, he succumbed two days afterwards without recovering consciousness. It was surmised that shrinkage of the canvas of the tail, through getting wet, had strained and broken its bamboo stretcher.

This autumn died Gaston Tissandier, at the age of fifty-six; and in the month of December, at a ripe old age, while still in full possession of intellectual vigour, Mr. Coxwell somewhat suddenly passed away. Always keenly interested in the progress of aeronautics; he had but recently, in a letter to the Standard, proposed a well-considered and practical method of employing Montgolfier reconnoitring balloons, portable, readily inflated, and especially suited to the war in South Africa. Perhaps the last letters of a private nature penned by Mr. Coxwell were to the writer and his daughter, full of friendly and valuable suggestion, and more particularly commenting on a recent scientific aerial voyage, which proved to be not only sensational, but established a record in English ballooning.

The great train of the November meteors, known as the Leonids, which at regular periods of thirty-three years had in the past encountered the earth’s atmosphere, was due, and over-due. The cause of this, and of their finally eluding observation, need only be very briefly touched on here. The actual meteoric train is known to travel in an elongated ellipse, the far end of which lies near the confines of the solar system, while at a point near the hither end the earth’s orbit runs slantingly athwart it, forming, as it were, a level crossing common to the two orbits, the earth taking some five or six hours in transit. Calculation shows that the meteor train is to be expected at this crossing every thirty-three and a third years, while the train is extended to such an enormous length–taking more than a year to draw clear–that the earth must needs encounter it ere it gets by, possibly even two years running. There could be no absolute certainty about the exact year, nor the exact night when the earth and the meteors would foregather, owing to the uncertain disturbance which the latter must suffer from the pull of the planetary bodies in the long journey out and home again among them. As is now known, this disturbing effect had actually dispersed the train.

The shower, which was well seen in 1866, was pretty confidently expected in 1899, and to guard against the mischance of cloudy weather, it was arranged that the writer should, on behalf of the Times newspaper, make an ascent on the right night to secure observations. Moreover, it was arranged that he should have, as chief assistant, his own daughter, an enthusiastic lady aeronaut, who had also taken part in previous astronomical work.

Unfortunately there were two nights, those of November 14th and 15th, when the expected shower seemed equally probable, and, taking counsel with the best authorities in the astronomical world, it seemed that the only course to avoid disappointment would be to have a balloon filled and moored in readiness for an immediate start, either on the first night or on the second.

This settled the matter from the astronomical side, but there was the aeronautical side also to be considered. A balloon of 56,000 cubic feet capacity was the largest available for the occasion, and a night ascent with three passengers and instruments would need plenty of lifting power to meet chance emergencies. Thus it seemed that a possible delay of forty-eight hours might entail a greater leakage of gas than could be afforded.

The leakage might be expected chiefly to occur at the valve in the head of the balloon, it being extremely difficult to render any form of mechanical valve gas tight, however carefully its joints be stopped with luting. On this account, therefore, it was determined that the balloon should be fitted with what is known as a solid or rending valve, consisting simply of balloon fabric tied hard and fast over the entire upper outlet, after the fashion of a jam pot cover. The outlet itself was a gaping hole of over 2 feet across; but by the time its covering had been carefully varnished over all leakage was sufficiently prevented, the one drawback to this method being the fact that the liberation of gas now admitted of no regulation. Pulling the valve line would simply mean opening the entire wide aperture, which could in no way be closed again.

The management of such a valve consists in allowing the balloon to sink spontaneously earthwards, and when it has settled near the ground, having chosen a desirable landing place, to tear open the so-called valve once and for all.

This expedient, dictated by necessity, seeming sufficient for the purpose at hand, preparations were proceeded with, and, under the management of Mr. Stanley Spencer, who agreed to act as aeronaut, a large balloon, with solid valve, was brought down to Newbury gas works on November 14th, and, being inflated during the afternoon, was full and made snug by sundown. But as the meteor radiant would not be well above the horizon till after midnight, the aeronautical party retired for refreshment, and subsequently for rest, when, as the night wore on, it became evident that, though the sky remained clear, there would be no meteor display that night. The next day was overcast, and by nightfall hopelessly so, the clouds ever thickening, with absence of wind or any indication which might give promise of a change. Thus by midnight it became impossible to tell whether any display were in progress or not. Under these circumstances, it might have been difficult to decide when to make the start with the best show of reason. Clearly too early a start could not subsequently be rectified; the balloon, once off, could not come back again; while, once liberated, it would be highly unwise for it to remain aloft and hidden by clouds for more than some two hours, lest it should be carried out to sea.

Happily the right decision under these circumstances was perfectly clear. Other things being equal, the best time would be about 4 a.m., by which period the moon, then near the full, would be getting low, and the two hours of darkness left would afford the best seeing. Leaving, then, an efficient outlook on the balloon ground, the party enjoyed for some hours the entertainment offered them by the Newbury Guildhall Club, and at 4 a.m. taking their seats in the car, sailed up into the calm chilly air of the November night.

But the chilliness did not last for long. A height of 1,500 feet was read by the Davy lamp, and then we entered fog–warm, wetting fog, through which the balloon would make no progress in spite of a prodigal discharge of sand. The fact was that the balloon, which had become chilled through the night hours, was gathering a great weight of moisture from condensation on its surface, and when, at last, the whole depth of the cloud, 1,500 feet, had been penetrated, the chill of the upper air crippled the balloon and sent her plunging down again into the mist, necessitating yet further expenditure of sand, which by this time had amounted to no less than 3 1/2 cwt. in twenty minutes. And then at last we reached our level, a region on the upper margin of the cloud floor, where evaporation reduced the temperature, that had recently been that of greenhouse warmth, to intense cold.

That evaporation was going on around us on a gigantic scale was made very manifest. The surface of the vast cloud floor below us was in a perfect turmoil, like that of a troubled sea. If the cloud surface could be compared to anything on earth it most resembled sea where waves are running mountains high. At one moment we should be sailing over a trough, wide and deep below us, the next a mighty billow would toss itself aloft and vanish utterly into space. Everywhere wreaths of mist with ragged fringes were withering away into empty air, and, more remarkable yet, was the conflict of wind which sent the cloud wrack flying simply in all directions.

For two hours now there was opportunity for observing at leisure all that could be made of the falling meteors. There were a few, and these, owing to our clear, elevated region, were exceptionally bright. The majority, too, were true Leonids, issuing from the radiant point in the “Sickle,” but these were not more numerous than may be counted on that night in any year, and served to emphasise the fact that no real display was in progress. The outlook was maintained, and careful notes made for two hours, at the end of which time the dawn began to break, the stars went in, and we were ready to pack up and come down.

But the point was that we were not coming down. We were at that time, 6 a.m., 4,000 feet high, and it needs no pointing out that at such an altitude it would have been madness to tear open our huge rending valve, thus emptying the balloon of gas. It may also be unnecessary to point out that in an ordinary afternoon ascent such a valve would be perfectly satisfactory, for under these circumstances the sun presently must go down, the air must grow chill, and the balloon must come earthward, allowing of an easy descent until a safe and suitable opportunity for rending the valve occurred; but now we knew that conditions were reversed, and that the sun was just going to rise.

And then it was we realised that we were caught in a trap. From that moment it was painfully evident that we were powerless to act, and were at the mercy of circumstances. By this time the light was strong, and, being well above the tossing billows of mist, we commanded an extended view on every side, which revealed, however, only the upper unbroken surface of the dense cloud canopy that lay over all the British Isles. We could only make a rough guess as to our probable locality. We knew that our course at starting lay towards the west, and if we were maintaining that course a travel of scarcely more than sixty miles would carry us out to the open sea. We had already been aloft for two hours, and as we were at an altitude at which fast upper currents are commonly met with, it was high time that, for safety, we should be coming down; yet it was morally certain that it would be now many hours before our balloon would commence to descend of its own accord by sheer slow leakage of gas, by which time, beyond all reasonable doubt, we must be carried far out over the Atlantic. All we could do was to listen intently for any sounds that might reach us from earth, and assure us that we were still over the land; and for a length of time such sounds were vouchsafed us–the bark of a dog, the lowing of cattle, the ringing trot of a horse on some hard road far down.

And then, as we were expecting, the sun climbed up into an unsullied sky, and, mounting by leaps and bounds, we watched the cloud floor receding beneath us. The effect was extremely beautiful. A description written to the Times the next morning, while the impression was still fresh, and from notes made at this period, ran thus:–” Away to an infinitely distant horizon stretched rolling billows of snowy whiteness, broken up here and there into seeming icefields, with huge fantastic hummocks. Elsewhere domes and spires reared themselves above the general surface, or an isolated Matterhorn towered into space. In some quarters it was impossible to look without the conviction that we actually beheld the outline of lofty cliffs overhanging a none too distant sea.” Shortly we began to hear loud reports overhead, resembling small explosions, and we knew what these were–the moist, shrunken netting was giving out under the hot sun and yielding now and again with sudden release to the rapidly expanding gas. It was, therefore, with grave concern, but with no surprise, that when we next turned to the aneroid we found the index pointing to 9,000 feet, and still moving upwards.

Hour after hour passed by, and, sounds having ceased to reach us, it remains uncertain whether or no we were actually carried out to sea and headed back again by contrary currents, an experience with which aeronauts, including the writer, have been familiar; but, at length, there was borne up to us the distant sound of heavy hammers and of frequent trains, from which we gathered that we were probably over Bristol, and it was then that the thought occurred to my daughter that we might possibly communicate with those below with a view to succour. This led to our writing the following message many times over on blank telegraph forms and casting them down:– “Urgent. Large balloon from Newbury travelling overhead above the clouds. Cannot descend. Telegraph to sea coast (coast-guards) to be ready to rescue.–Bacon and Spencer.”

While thus occupied we caught the sound of waves, and the shriek of a ship’s siren. We were crossing a reach of the Severn, and most of our missives probably fell in the sea. But over the estuary there must have been a cold upper current blowing, which crippled our balloon, for the aneroid presently told of a fall of 2,000 feet. It was now past noon, and to us the turn of the tide was come. Very slowly, and with strange fluctuations, the balloon crept down till it reached and became enveloped in the cloud below, and then the end was near. The actual descent occupied nearly two hours, and affords a curious study in aerostation. The details of the balloon’s dying struggles and of our own rough descent, entailing the fracture of my daughter’s arm, are told in another volume.*

We fell near Neath, Glamorganshire, only one and a half miles short of the sea, completing a voyage which is a record in English ballooning–ten hours from start to finish.

* “By Land and Sky,” by the Author.

CHAPTER XXVI. RECENT AERONAUTICAL EVENTS.

The first trial of the Zeppelin air ship was arranged to take place on June 30th, 1900, a day which, from absence of wind, was eminently well suited for the purpose; but the inflation proved too slow a process, and operations were postponed to the morrow. The morrow, however, was somewhat windy, causing delay, and by the time all was in readiness darkness had set in and the start was once more postponed. On the evening of the third day the monster craft was skilfully and successfully manoeuvred, and, rising with a very light wind, got fairly away, carrying Count Zeppelin and four other persons in the two cars. Drifting with the wind, it attained a height of some 800 or 900 feet, at which point the steering apparatus being brought into play it circled round and faced the wind, when it remained stationary. But not for long. Shortly it began to descend and, sinking gradually, gracefully, and in perfect safety, in about nine minutes it reached and rested on the water, when it was towed home.

A little later in the month, July, another trial was made, when a wind was blowing estimated at sixteen miles an hour. As on the previous occasion, the direct influence of the sun was avoided by waiting till evening hours. It ascended at 8 p.m., and the engines getting to work it made a slow progress of about two miles an hour against the wind for about 3 1/2 miles, when one of the rudders gave way, and the machine was obliged to descend.

On the evening of October 24th of the same year, in very calm weather and with better hope, another ascent was made. On this occasion, however, success was frustrated by one of the rear rudders getting foul of the gear, followed by the escape of gas from one of the balloons.

Another and more successful trial took place in the same month, again in calm atmosphere. Inferior gas was employed, and it would appear that the vessel had not sufficient buoyancy. It remained aloft for a period of twenty minutes, during which it proved perfectly manageable, making a graceful journey out and home, and returning close to its point of departure. This magnificent air ship, the result of twenty years of experiment, has since been abandoned and broken up; yet the sacrifice has not been without result. Over and above the stimulus which Count Zeppelin’s great endeavour has given to the aeronautical world, two special triumphs are his. He has shown balloonists how to make a perfectly gas-tight material, and has raised powerful petroleum motors in a balloon with safety.

In the early part of 1900 it was announced that a member of the Paris Aero Club, who at the time withheld his name (M. Deutsch) offered a prize of 100,000 francs to the aeronaut who, either in a balloon or flying machine, starting from the grounds of the Aero Club at Longchamps, would make a journey round the Eiffel Tower, returning to the starting place within half an hour. The donor would withdraw his prize if not won within five years, and in the meanwhile would pay 4,000 francs annually towards the encouragement of worthy experimenters.

It was from this time that flying machines in great variety and goodly number began to be heard of, if not actually seen. One of the earliest to be announced in the Press was a machine invented by the Russian, Feedoroff, and the Frenchman, Dupont. Dr. Danilewsky came forward with a flying machine combining balloon and aeroplane, the steering of which would be worked like a velocipede by the feet of the aeronaut.

Mr. P. Y. Alexander, of Bath, who had long been an enthusiastic balloonist, and who had devoted a vast amount of pains, originality, and engineering skill to the pursuit of aeronautics, was at this time giving much attention to the flying machine, and was, indeed, one of the assistants in the first successful launching of the Zeppelin airship. In concert with Mr. W. G. Walker, A.M.I.C.E., Mr. Alexander carried out some valuable and exhaustive experiments on the lifting power of air propellers, 30 feet in diameter, driven by a portable engine. The results, which were of a purely technical nature, have been embodied in a carefully compiled memoir.

An air ship now appeared, invented by M. Rose, consisting of two elongated vessels filled with gas, and carrying the working gear and car between them. The machine was intentionally made heavier than air, and was operated by a petrol motor of 12-horse power.

It was now that announcements began to be made to the effect that, next to the Zeppelin air ship, M. Santos Dumont’s balloon was probably attracting most of the attention of experts. The account given of this air vessel] by the Daily Express was somewhat startling. The balloon proper was compared to a large torpedo. Three feet beneath this hangs the gasoline motor which is to supply the power. The propeller is 12 feet in diameter, and is revolved so rapidly by the motor that the engine frequently gets red hot. The only accommodation for the traveller is a little bicycle seat, from which the aeronaut will direct his motor and steering gear by means of treadles. Then the inclination or declination of his machine must be noted on the spirit level at his side, and the 200 odd pounds of ballast must be regulated as the course requires.

A more detailed account of this navigable balloon was furnished by a member of the Paris Aero Club. From this authority we learn that the capacity of the balloon was 10,700 cubic feet. It contained an inner balloon and an air fan, the function of which was to maintain the shape of the balloon when meeting the wind, and the whole was operated by a 10-horse power motor capable of working the screw at 100 revolutions per minute.

But before the aerial exploits of Santos Dumont had become famous, balloons had again claimed public attention. On August 1st Captain Spelterini, with two companions, taking a balloon and 180 cylinders of hydrogen to the top of the Rigi and ascending thence, pursued a north-east course, across extensive and beautiful tracts of icefield and mountain fastnesses unvisited by men. The descent, which was difficult and critical, was happily manoeuvred. This took place on the Gnuetseven, a peak over 5,000 feet high, the plateau on which the voyagers landed being described as only 50 yards square, surrounded by precipices.

On the 10th of September following the writer was fortunate in carrying out some wireless telegraphy experiments in a balloon, the success of which is entirely due to the unrivalled skill of Mr. Nevil Maskelyne, F.R.A.S., and to his clever adaptation of the special apparatus of his own invention to the exigencies of a free balloon. The occasion was the garden party at the Bradford meeting of the British Association, Admiral Sir Edmund Fremantle taking part in the voyage, with Mr. Percival Spencer in charge. The experiment was to include the firing of a mine in the grounds two minutes after the balloon had left, and this item was entirely successful. The main idea was to attempt to establish communication between a base and a free balloon retreating through space at a height beyond practicable gun shot. The wind was fast and squally, and the unavoidable rough jolting which the car received at the start put the transmitting instrument out of action. The messages, however, which were sent from the grounds at Lister Park were received and watched by the occupants of the car up to a distance of twenty miles, at which point the voyage terminated.

On September 30th, and also on October 9th, of this year, took place two principal balloon races from Vincennes in connection with the Paris Exposition. In the first race, among those who competed were M. Jacques Faure, the Count de la Vaulx, and M. Jacques Balsan. The Count was the winner, reaching Wocawek, in Russian Poland, a travel of 706 miles, in 21 hours 34 minutes. M. Balsan was second, descending near Dantzig in East Prussia, 757 miles, in 22 hours. M. Jacques Faure reached Mamlitz, in East Prussia, a distance of 753 miles.

In the final race the Count de la Vaulx made a record voyage of 1,193 miles, reaching Korosticheff, in Russia, in 35 hours 45 minutes, attaining a maximum altitude of 18,810 feet. M. J. Balsan reached a greater height, namely, 21,582 feet, travelling to Rodom, in Russia, a distance of 843 miles, in 27 hours 25 minutes.

Some phenomenal altitudes were attained at this time. In September, 1898, Dr. Berson, of Berlin, ascended from the Crystal Palace in a balloon inflated with hydrogen, under the management of Mr. Stanley Spencer, oxygen being an essential part of the equipment. The start was made at 5 p.m., and the balloon at first drifted south-east, out over the mouth of the Thames, until at an altitude of 10,000 feet an upper current changed the course to southwest, the balloon mounting rapidly till 23,000 feet was reached, at which height the coast of France was plainly seen. At 25,000 feet both voyagers were gasping, and compelled to inhale oxygen. At 27,500 feet, only four bags of ballast being left, the descent was commenced, and a safe landing was effected at Romford.

Subsequently Dr. Berson, in company with Dr. Suring, ascending from Berlin, attained an altitude of 34,000 feet. At 30,000 feet the aeronauts were inhaling oxygen, and before reaching their highest point both had for a considerable time remained unconscious.

In 1901 a new aeroplane flying machine began to attract attention, the invention of Herr Kress. A novel feature of the machine was a device to render it of avail for Arctic travel. In shape it might be compared to an iceboat with two keels and a long stem, the keels being adapted to run on ice or snow, while the boat would float on water. Power was to be derived from a petrol motor.

At the same period M. Henry Sutor was busy on Lake Constance with an air ship designed also to float on water. Then Mr. Buchanan followed with a fish-shaped vessel, one of the most important specialities of which consisted in side propellers, the surfaces of which were roughened with minute diagonal grooves to effect a greater grip on the air.

No less original was the air ship, 100 feet long, and carrying 18,000 cubic feet of gas, which Mr. W. Beedle was engaged upon. In this machine, besides the propellers for controlling the horizontal motion, there was one to regulate vertical motion, with a view of obviating expenditure of gas or ballast.

But by this time M. Santos Dumont, pursuing his hobby with unparalleled perseverance, had built in succession no less than six air ships, meeting with no mean success, profiting by every lesson taught by failures, and making light of all accidents, great or small. On July 15th, 1901, he made a famous try for the Deutsch prize in a cigar-shaped balloon, 110 feet long, 19,000 cubic feet capacity, carrying a Daimler oil motor of 15-horse power. The day was not favourable, but, starting from the Parc d’Aerostation, he was abreast of the Eiffel Tower in thirteen minutes, circling round which, and battling against a head wind, he reached the grounds of the Aero Club in 41 minutes from the start, or 11 minutes late by the conditions of the prize. A cylinder had broken down, and the balance of the vessel had become upset.

Within a fortnight–July 29th–in favourable weather, he made another flight, lasting fifteen minutes, at the end of which he had returned to his starting ground. Then on August 8th a more momentous attempt came off. Sailing up with a rapid ascent, and flying with the wind, Santos Dumont covered the distance to the Tower in five minutes only, and gracefully swung round; but, immediately after, the wind played havoc, slowing down the motor, at the same time damaging the balloon, and causing an escape of gas. On this Santos Dumont, ascending higher into the sky, quitted the car, and climbed along the keel to inspect, and, if possible, rectify the motor, but with little success. The balloon was emptying, and the machine pitched badly, till a further rent occurred, when it commenced falling hopelessly and with a speed momentarily increasing.

Slanting over a roof, the balloon caught a chimney and tore asunder; but the wreck, also catching, held fast, while the car hung helplessly down a blank wall. In this perilous predicament great coolness and agility alone averted disaster, till firemen were able to come to the rescue.

The air ship was damaged beyond repair, but by September 6th another was completed, and on trial appeared to work well until, while travelling at speed, it was brought up and badly strained by the trail rope catching in trees.

Early in the next month the young Brazilian was aloft again, with weather conditions entirely in his favour; but again certain minor mishaps prevented his next struggle for the prize, which did not take place till the 19th. On this day a light cross wind was blowing, not sufficient, however, seriously to influence the first stage of the time race, and the outward journey was accomplished with a direct flight in nine minutes. On rounding the tower, however, the wind began to tell prejudicially, and the propeller became deranged. On this, letting his vessel fall off from the wind, Santos Dumont crawled along the framework till he reached the motor, which he succeeded in again setting in working order, though not without a delay of several minutes and some loss of ground. From that point the return journey was accomplished in eight minutes, and the race was, at the time, declared lost by 40 seconds only.

The most important and novel feature in the air ships constructed by Santos Dumont was the internal ballonet, inflated automatically by a ventilator, the expedient being designed to preserve the shape of the main balloon itself while meeting the wind. On the whole, it answered well, and took the place of the heavy wire cage used by Zeppelin.

M. de Fonvielle, commenting on the achievements of Santos Dumont, wrote:–“It does not appear that he has navigated his balloon against more than very light winds, but in his machinery he has shown such attention to detail that it may reasonably be expected that if he continues to increase his motive power he will, ere long, exceed past performances.”

Mr. Chanute has a further word to say about the possibility of making balloons navigable. He considers that their size will have to be great to the verge of impracticability and the power of the motor enormous in proportion to its weight. As to flying machines, properly so called, he calculates the best that has been done to be the sustaining of from 27 lbs. to 55 lbs. per horse power by impact upon the air. But Mr. Chanute also argues that the equilibrium is of prime importance, and on this point there could scarcely be a greater authority. No one of living men has given more attention to the problem of “soaring,” and it is stated that he has had about a thousand “slides” made by assistants, with different types of machine, and all without the slightest accident.

Many other aerial vessels might be mentioned. Mr. T. H. Bastin, of Clapham, has been engaged for many years on a machine which should imitate bird flight as nearly as this may be practicable.

Baron Bradsky aims at a navigable balloon on an ambitious scale. M. Tatin is another candidate for the Deutsch prize. Of Dr. Barton’s air ship more is looked for, as being designed for the War Office. It is understood that the official requirements demand a machine which, while capable of transporting a man through the air at a speed of 13 miles an hour, can remain fully inflated for 48 hours. One of the most sanguine, as well as enterprising, imitators of Santos Dumont was a fellow countryman, Auguste Severo. Of his machine during construction little could be gathered, and still less seen, from the fact that the various parts were being manufactured at different workshops, but it was known to be of large size and to be fitted with powerful motors. This was an ill-fated vessel. At an early hour on May 12th of this year, 1902, all Paris was startled by a report that M. Severo and his assistant, M. Sachet had been killed while making a trial excursion. It appears that at daybreak it had been decided that the favourable moment for trial had arrived. The machinery was got ready, and with little delay the air vessel was dismissed and rose quietly and steadily into the calm sky. The Daily Mail gives the following account of what ensued:–

“For the first few minutes all went well, and the motor seemed to be working satisfactorily. The air ship answered the helm readily, and admiring exclamations rose from the crowd…. But as the vessel rose higher she was seen to fall off from the wind, while the aeronauts could be seen vainly endeavouring to keep her head on. Then M. Severo commenced throwing out ballast…. All this time the ship was gradually soaring higher and higher until, just as it was over the Montparnasse Cemetery, at the height of 2,000 feet, a sheet of flame was seen to shoot up from one of the motors, and instantly the immense silk envelope containing 9,000 cubicfeet of hydrogen was enveloped in leaping tongues of fire…. As soon as the flames came in contact with the gas a tremendous explosion followed, and in an instant all that was left of the air ship fell to the earth.” Both aeronauts were dashed to pieces. It was thought that the fatality was caused through faulty construction, the escape valve for the gas being situated only about nine feet from the motor. It was announced by Count de la Vaulx that during the summer of 1901 he would attempt to cross the Mediterranean by a balloon, provisioned for three weeks, maintaining communication with the coast during his voyage by wireless telegraphy and other methods of signalling. He was to make use of the “Herve Deviator,” or steering apparatus, which may be described as a series of cupshaped plates dipping in the water at the end of a trail rope. By means of controlling cords worked from the car, the whole series of plates could be turned at an angle to the direction of the wind, by which the balloon’s course would be altered. Count de la Vaulx attempted this grand journey on October 12th, starting from Toulon with the intention of reaching Algiers, taking the precaution, however, of having a cruiser in attendance. When fifty miles out from Marseilles a passing steamer received from the balloon the signal, “All’s well”; but the wind had veered round to the east, and, remaining persistently in this quarter, the Count abandoned his venture, and, signalling to the cruiser, succeeded in alighting on her deck, not, however, before he had completed the splendid and record voyage of 41 hours’ duration.

CHAPTER XXVII. THE POSSIBILITIES OF BALLOONS IN WARFARE.

Clearly the time has not yet arrived when the flying machine will be serviceable in war. Yet we are not without those theorisers who, at the present moment, would seriously propose schemes for conveying dynamite and other explosives by air ship, or dropping them over hostile forces or fortresses, or even fleets at sea. They go yet further, and gravely discuss the point whether such warfare would be legitimate. We, however, may say at once, emphatically, that any such scheme is simply impracticable. It must be abundantly evident that, so far, no form of dirigible air ship exists which could be relied on to carry out any required manoeuvre in such atmospheric conditions as generally prevail. If, even in calm and favourable weather, more often than not motors break down, or gear carries away, what hope is there for any aerial craft which would attempt to battle with such wind currents as commonly blow aloft?

And when we turn to the balloon proper, are chances greatly improved? The eminently practical aeronaut, John Wise, as was told in Chapter XII., prepared a scheme for the reduction of Vera Cruz by the agency of a balloon. Let us glance at it. A single balloon was to suffice, measuring 100 feet in diameter, and capable of raising in the gross 30,000 lbs. To manoeuvre this monstrous engine he calculates he would require a cable five miles long, by means of which he hoped, in some manner, to work his way directly over the fortress, and to remain poised at that point at the height of a mile in the sky. Once granted that he could arrive and maintain himself at that position, the throwing out of combustibles would be simple, though even then the spot where they would alight after the drop of a mile would be by no means certain. It is also obvious that a vast amount of gas would have to be sacrificed to compensate for the prodigal discharge of ballast in the form of missiles.

The idea of manoeuvring a balloon in a wind, and poising it in the manner suggested, is, of course, preposterous; and when one considers the attempt to aim bombs from a moving balloon high in air the case becomes yet more absurd. Any such missile would partake of the motion of the balloon itself, and it would be impossible to tell where it would strike the earth.

To give an example which is often enough tried in balloon travel when the ground below is clear. A glass bottle (presumably empty) is cast overboard and its fall watched. It is seen not to be left behind, but to keep pace with the balloon, shrinking gradually to an object too small to be discerned, except when every now and then a ray of sunlight reflected off it reveals it for a moment as it continues to plunge downwards. After a very few seconds the impression is that it is about to reach the earth, and the eye forms a guess at some spot which it will strike; but the spot is quickly passed, and the bottle travels far beyond across a field, over the further fence, and vastly further yet; indeed, inasmuch as to fall a mile in air a heavy body may take over twenty seconds–and twenty seconds is long to those who watch–it is often impossible to tell to two or three fields where it will finally settle.

All this while the risk that a balloon would run of being riddled by bullets, shrapnel, or pom-poms has not been taken into account, and as to the estimate of this risk there is some difference of opinion. The balloon corps and the artillery apparently approach the question with different bias. On the one hand, it is stated with perfect truth that a free balloon, which is generally either rising or falling, as well as moving across country, is a hard object to hit, and a marksman would only strike it with a chance or blundering shot; but, on the other hand let us take the following report of three years ago.

The German artillery had been testing the efficiency of a quick-firing gun when used against a balloon, and they decided that the latter would have no chance of escape except at night. A German kite-balloon was kept moving at an altitude of 600 metres, and the guns trained upon it were distant 3,000 metres. It was then stated that after the third discharge of the rapid firing battery the range was found, when all was at once over with the balloon; for, not only was it hit with every discharge, but it was presently set on fire and annihilated.

But, in any case, the antique mode of keeping a balloon moored at any spot as a post of observation must be abandoned in modern warfare. Major Baden-Powell, speaking from personal experience in South Africa, has shown how dangerous, or else how useless, such a form of reconnaissance has become. “I remember,” he says, “at the battle of Magersfontein my company was lying down in extended order towards the left of our line. We were perfectly safe from musketry fire, as we lay, perhaps, two miles from the Boer trenches, which were being shelled by some of our guns close by. The enemy’s artillery was practically silent. Presently, on looking round, I descried our balloon away out behind us about two miles off. Then she steadily rose and made several trips to a good height, but what could be seen from that distance? When a large number of our troops were ranged up within 800 yards of the trenches, and many more at all points behind them, what useful information could be obtained by means of the balloon four miles off?”

The same eminent authority insists on the necessity of an observing war balloon making short ascents. The balloon, in his opinion, should be allowed to ascend rapidly to its full height, and with as little delay as possible be hauled down again. Under these conditions it may then be well worth testing whether the primitive form of balloon, the Montgolfier, might not be the most valuable. Instead of being made, as the war balloon is now, of fragile material, and filled with costly gas difficult to procure, and which has to be conveyed in heavy and cumbersome cylinders, a hot air balloon could be rapidly carried by hand anywhere where a few men could push their way. It is of strong material, readily mended if torn, and could be inflated for short ascents, if not by mere brush wood, then by a portable blast furnace and petroleum.

But there is a further use for balloons in warfare not yet exploited. The Siege of Paris showed the utility of free balloons, and occasions arise when their use might be still further extended. The writer pointed out that it might have been very possible for an aeronaut of experience, by choosing the right weather and the right position along the British lines, to have skilfully manoeuvred a free balloon by means of upper currents, so as to convey all-important intelligence to besieged Mafeking, and he proved that it would have sufficed if the balloon could have been “tacked” across the sky to within some fifteen miles of the desired goal.

The mode of signalling which he proposed was by means of a “collapsing drum,” an instrument of occasional use in the Navy. A modification of this instrument, as employed by the writer, consisted of a light, spherical, drum-shaped frame of large size, which, when covered with dark material and hung in the clear below the car of a lofty balloon, could be well seen either against blue sky or grey at a great distance. The so-called drum could, by a very simple contrivance, readily worked from the car, be made to collapse into a very inconspicuous object, and thus be capable of displaying Morse Code signals. A long pause with the drum extended–like the long wave of a signalling flag–would denote a “dash,” and a short pause a “dot,” and these motions would be at once intelligible to anyone acquainted with the now universal Morse Code system.

Provided with an apparatus of the kind, the writer made an ascent from Newbury at a time when the military camps were lying on Salisbury Plain at a distance of nearly twenty miles to the south-west. The ground wind up to 2,500 feet on starting was nearly due north, and would have defeated the attempt; again, the air stream blowing above that height was nearly due east, which again would have proved unsuitable. But it was manifestly possible to utilise the two currents, and with good luck to zig-zag one’s course so as to come within easy signalling distance of the various camps; and, as a matter of fact, we actually passed immediately over Bulford Camp, with which we exchanged signals, while two other camps lay close to right and left of us. Fortune favouring us, we had actually hit our mark, though it would have been sufficient for the experiment had our course lain within ten miles right or left.

Yet a further use for the balloon in warfare remains untried in this country. Acting under the advice of experts in the Service, the writer, in the early part of the present year, suggested to the Admiralty the desirability of experimenting with balloons as a means of detecting submarine engines of war. It is well known that reefs and shoals can generally be seen from a cliff or mast head far more clearly than from the deck or other position near the surface of the water. Would not, then, a balloon, if skilfully manoeuvred, serve as a valuable post of observation? The Admiralty, in acknowledging the communication, promised to give the matter their attention; but by the month of June the Press had announcements of how the self-same experiments had been successfully carried through by French authorities, while a few days later the Admiralty wrote, “For the present no need is seen for the use of a captive balloon to detect submarines.”

Among many and varied ballooning incidents which have occurred to the writer, there are some which may not unprofitably be compared with certain experiences already recorded of other aeronauts. Thunderstorms, as witnessed from a balloon, have already been casually described, and it may reasonably be hoped that the observations which have, under varying circumstances, been made at high altitudes may throw some additional light on this familiar, though somewhat perplexing, phenomenon.

To begin with, it seems a moot point whether a balloon caught in a thunderstorm is, or is not, in any special danger of being struck. It has been argued that immunity under such circumstances must depend upon whether a sufficiently long time has elapsed since the balloon left the earth to allow of its becoming positively electrified by induction from the clouds or by rain falling upon its surface. But there are many other points to be considered. There is the constant escape of gas from the mouth; there is the mass of pointed metal in the anchor; and, again, it is conceivable that a balloon rapidly descending out of a thunderstorm might carry with it a charge residing on its moistened surface which might manifest itself disastrously as the balloon reached the earth.

Instances seem to have been not infrequent of balloons encountering thunderstorms; but, unfortunately, in most cases the observers have not had any scientific training, or the accounts which are to hand are those of the type of journalist who is chiefly in quest of sensational copy.

Thus there is an account from America of a Professor King who made an ascent from Burlington, Iowa, just as a thunderstorm was approaching, with the result that, instead of scudding away with the wind before the storm, he was actually, as if by some attraction, drawn into it. On this his aim was to pierce through the cloud above, and then follows a description which it is hard to realise:–“There came down in front of him, and apparently not more than 50 feet distant, a grand discharge of electricity.” Then he feels the car lifted, the gas suddenly expands to overflowing, and the balloon is hurled through the cloud with inconceivable velocity, this happening several times, with tremendous oscillations of the car, until the balloon is borne to earth in a torrent of rain. We fancy that many practical balloonists will hardly endorse this description.

But we have another, relating to one of the most distinguished aeronauts, M. Eugene Godard, who, in an ascent with local journalists, was caught in a thunderstorm. Here we are told–presumably by the journalists–that “twice the lightning flashed within a few yards of the terror-stricken crew.”

Once again, in an ascent at Derby, a spectator writes:–“The lightning played upon the sphere of the balloon, lighting it up and making things visible through it.” This, however, one must suppose, can hardly apply to the balloon when liberated.

But a graphic description of a very different character given in the “Quarterly Journal of the Royal Meteorological Society” for January, 1901, is of real value. It appears that three lieutenants of the Prussian Balloon Corps took charge of a balloon that ascended at Berlin, and, when at a height of 2,300 feet, became enveloped in the mist, through which only occasional glimpses of earth were seen. At this point a sharp, crackling sound was heard at the ring, like the sparking of a huge electrical machine, and, looking up, the voyagers beheld sparks apparently some half-inch thick, and over two feet in length, playing from the ring. Thunder was heard, but–and this may have significance–only before and after the above phenomenon.

Another instructive experience is recorded of the younger Green in an ascent which he made from Frankfort-on-the-Maine. On this occasion he relates that he encountered a thunderstorm, and at a height of 4,400 feet found himself at the level where the storm clouds were discharging themselves in a deluge. He seems to have had no difficulty in ascending through the storm into the clear sky above, where a breeze from another quarter quickly carried him away from the storm centre.

This co-existence, or conflict of opposite currents, is held to be the common characteristic, if not the main cause, of thunderstorms, and tallies with the following personal experience. It was in typical July weather of 1900 that the writer and his son, accompanied by Admiral Sir Edmund Fremantle and Mr. Percival Spencer, made an evening ascent from Newbury. It had been a day of storms, but about 5 p.m., after what appeared to be a clearing shower, the sky brightened, and we sailed up into a cloudless heaven. The wind, at 3,000 feet, was travelling at some thirty miles an hour, and ere the distance of ten miles had been covered a formidable thunder pack was seen approaching and coming up dead against the wind. Nothing could be more evident than that the balloon was travelling rapidly with a lower wind, while the storm was being borne equally rapidly on an upper and diametrically opposite current. It proved one of the most severe thunderstorms remembered in the country. It brooded for five hours over Devizes, a few miles ahead. A homestead on our right was struck and burned to the ground, while on our left two soldiers were killed on Salisbury Plain. The sky immediately overhead was, of course, hidden by the large globe of the balloon, but around and beneath us the storm seemed to gather in a blue grey mist, which quickly broadened and deepened till, almost before we could realise it, we found ourselves in the very heart of the storm, the lightning playing all around us, and the sharp hail stinging our faces.

The countrymen below described the balloon as apparently enveloped by the lightning, but with ourselves, though the flashes were incessant, and on all sides, the reverberations of the thunder were not remarkable, being rather brief explosions in which they resembled the thunder claps not infrequently described by travellers on mountain heights.

The balloon was now descending from a double cause: the weight of moisture suddenly accurnulated on its surface, and the very obvious downrush of cold air that accompanied the storm of pelting hail. With a very limited store of ballast, it seemed impossible to make a further ascent, nor was this desirable. The signalling experiments on which we were intent could not be carried on in such weather. The only course was to descend, and though this was not at once practicable, owing to Savernake Forest being beneath us, we effected a safe landing in the first available clearing.

As has been mentioned, Mr. Glaisher and other observers have recorded several remarkable instances of opposite wind currents being met with at moderate altitudes. None, however, can have been more noteworthy or surprising than the following experience Of the writer on Whit Monday of 1899. The ascent was under an overcast sky, from the Crystal Palace at 3 p.m., at which hour a cold drizzle was settling in with a moderate breeze from the east. Thus, starting from the usual filling ground near the north tower, the balloon sailed over the body of the Palace, and thence over the suburbs towards the west till lost in the mist. We then ascended through 1,500 feet of dense, wetting cloud, and, emerging in bright sunshine, continued to drift for two hours at an average altitude of some 3,000 feet; 1,000 feet below us was the ill-defined, ever changing upper surface of the dense cloud floor, and it was no longer possible to determine our course, which we therefore assumed to have remained unchanged. At length, however, as a measure of prudence, we determined to descend through the clouds sufficiently to learn something of our whereabouts, which we reasonably expected to be somewhere in Surrey or Berks. On emerging, however, below the cloud, the first object that loomed out of the mist irnmediately below us was a cargo vessel, in the rigging of which our trail rope was entangling itself. Only by degrees the fact dawned upon us that we were in the estuary of the Thames, and beating up towards London once again with an cast wind. Thus it became evident that at the higher level, unknown to ourselves, we had been headed back on our course, for two hours, by a wind diametrically opposed to that blowing on the ground.

Two recent developments of the hot-air war balloon suggest great possibilities in the near future. One takes the form of a small captive, carrying aloft a photographic camera directed and operated electrically from the ground. The other is a self-contained passenger balloon of large dimensions, carrying in complete safety a special petroleum burner of great power. These new and important departures are mainly due to the mechanical genius of Mr. J. N. Maskelyne, who has patented and perfected them in conjunction with the writer.

CHAPTER XXVIII. THE CONSTITUTION OF THE AIR.

Some fair idea of the conditions prevailing in the upper air may have been gathered from the many and various observations already recorded. Stating the case broadly, we may assert that the same atmospheric changes with which we are familiar at the level of the earth are to be found also at all accessible heights, equally extensive and equally sudden.

Standing on an open heath on a gusty day, we may often note the rhythmic buffeting of the wind, resembling the assault of rolling billows of air. The evidence of these billows has been actually traced far aloft in balloon travel, when aeronauts, looking down on a wind-swept surface of cloud, have observed this surface to be thrown into a series of rolls of vapour, which were but vast and veritable waves of air. The interval between successive crests of these waves has on one occasion been estimated at approximately half a mile. We have seen how these air streams sometimes hold wide and independent sway at different levels. We have seen, too, how they sometimes meet and mingle, not infrequently attended with electrical disturbance

Through broad drifts of air minor air streams would seem often literally to “thread” their way, breakng up into filaments or wandering rills of air. In the voyage across Salisbury Plain lately described, while the balloon was being carried with the more sluggish current, a number of small parachutes were dropped out at frequent intervals and carefully watched. These would commonly attend the balloon for a little while, until, getting into some minor air stream, they would suddenly and rapidly diverge at such wide angles as to suggest that crossing our actual course there were side paths, down which the smaller bodies became wafted.

On another occasion the writer met with strongly marked and altogether exceptional evidence of the vehemence and persistence of these minor aerial streamlets. It was on an occasion in April weather, when a heavy overcast sky blotted out the upper heavens. In the cloud levels the wind was somewhat sluggish, and for an hour we travelled at an average speed of a little over twenty miles an hour, never higher than 3,000 feet. At this point, while flying over Hertfordshire, we threw out sufficient ballast to cause the balloon to rise clear of the hazy lower air, and coming under the full influence of the sun, then in the meridian, we shot upwards at considerable speed, and soon attained an altitude of three miles. But for a considerable portion of this climb–while, in fact, we were ascending through little less than a mile of our upward course–we were assailed by impetuous cross currents, which whistled through car and rigging and smote us fairly on the cheek. It was altogether a novel experience, and the more remarkable from the fact that our main onward course was not appreciably diverted.

Then we got above these currents, and remained at our maximum level, while we floated, still at only a moderate speed, the length of a county. The descent then began, and once again, while we dropped through the same disturbed region, the same far-reaching and obtrusive cross-current assailed us. It was quite obvious that the vehement currents were too slender to tell largely upon the huge surface of the balloon, as it was being swept steadily onwards by the main wind, which never varied in direction from ground levels up to the greatest height attained.

This experience is but confirmation of the story of the wind told by the wind gauges on the Forth Bridge. Here the maximum pressure measured on the large gauge of 300 square feet is commonly considerably less than that on the smaller gauge, suggesting that the latter must be due to threads of air of limited area and high velocity.

Further and very valuable light is thrown on the peculiar ways of the wind, now being considered, by Professor Langley in the special researches of his to which reference has already been made. This eminent observer and mathematician, suspecting that the old-fashioned instruments, which only told what the wind had been doing every hour, or at best every minute, gave but a most imperfect record, constructed delicate gauges, which would respond to every impulse and give readings from second to second.

In this way he established the fact that the wind, far from being a body of even approximate uniformity, is under most ordinary conditions irregular almost beyond conception. Further, that the greater the speed the greater the fluctuations, so that a high wind has to be regarded as “air moving in a tumultuous mass,” the velocity at one moment perhaps forty miles an hour, then diminishing to an almost instantaneous calm, and then resuming.” In fact, in the very nature of the case, wind is not the result of one simple cause, but of an infinite number of impulses and changes, perhaps long passed, which are preserved in it, and which die only slowly away.”

When we come to take observations of temperature we find the conditions in the atmosphere above us to be at first sight not a little complex, and altogether different in day and night hours. From observations already recorded in this volume–notably those of Gay Lussac, Welsh, and Glaisher–it has been made to appear that, in ascending into the sky in daytime, the temperature usually falls according to a general law; but there are found regions where the fall of temperature becomes arrested, such regions being commonly, though by no means invariably, associated with visible cloud. It is probable, however, that it would be more correct not to interpret the presence of cloud as causing manifestation of cold, but rather to regard the meeting of warm and cold currents as the cause of cloud.

The writer has experimented in the upper regions with a special form of air thermometer of great sensibility, designed to respond rapidly to slight variations of temperature. Testing this instrument on one occasion in a room of equable warmth, and without draughts, he was puzzled by seeing the index in a capillary tube suddenly mounting rapidly, due to some cause which was not apparent, till it was noticed that the parlour cat, attracted by the proceedings, had approached near the apparatus. The behaviour of this instrument when slung in the clear some distance over the side of the balloon car, and carefully watched, suggests by its fitful, sudden, and rapid changes that warmer currents are often making their way in such slender wandering rills as have been already pictured as permeating the broader air streams. During night hours conditions are reversed. The warmer air radiated off the earth through the day has then ascended. It will be found at different heights, lying in pools or strata, possibly resembling in form, could they be seen, masses of visible cloud.

The writer has gathered from night voyages instructive and suggestive facts with reference to the ascent of air streams, due to differences of temperature, particularly over London and the suburbs, and it is conceivable that in such ascending streams may lie a means of dealing successfully with visitations of smoke and fog.

One lesson taught by balloon travel has been that fog or haze will come or go in obedience to temperature variations at low levels. Thus thick haze has lain over London, more particularly over the lower parts, at sundown. Then through night hours, as the temperature of the lower air has become equalised, the haze has completely disappeared, but only to reassert itself at dawn.

A description of the very impressive experience of a night sail over London has been reserved, but should not be altogether omitted. Glaisher, writing of the spectacle as he observed it nearly forty years ago, describes London seen at night from a balloon at a distance as resembling a vast conflagration. When actually over the town, a main thoroughfare like the Commercial Road shone up like a line of brilliant fire; but, travelling westward, Oxford Street presented an appearance which puzzled him. “Here the two thickly studded rows of brilliant lights were seen on either side of the street, with a narrow, dark space between, and this dark space was bounded, as it were, on both sides by a bright fringe like frosted silver.” Presently he discovered that this rich effect was caused by the bright illumination of the shop lights on the pavements.”

London, as seen from a balloon on a clear moonlight night in August a year ago (1901), wore a somewhat altered appearance. There were the fairy lamps tracing out the streets, which, though dark centred, wore their silver lining; but in irregular patches a whiter light from electric arc lamps broadened and brightened and shone out like some pyrotechnic display above the black housetops. Through the vast town ran a blank, black channel, the river, winding on into distance, crossed here and there by bridges showing as bright bands, and with bright spots occasionally to mark where lay the river craft. But what was most striking was the silence. Though the noise of London traffic as heard from a balloon has diminished of late years owing to the better paving, yet in day hours the roar of the streets is heard up to a great height as a hard, harsh, grinding din. But at night, after the last ‘bus has ceased to ply, and before the market carts begin lumbering in, the balloonist, as he sails over the town, might imagine that he was traversing a City of the Dead.

It is at such times that a shout through a speaking trumpet has a most startling effect, and more particularly a blast on a horn. In this case after an interval of some seconds a wild note will be flung back from the house-tops below, answered and re-answered on all sides as it echoes from roof to roof–a wild, weird uproar that awakes suddenly, and then dies out slowly far away.

Experiments with echoes from a balloon have proved instructive. If, when riding at a height, say, of 2,000 feet, a charge of gun-cotton be fired electrically 100 feet below the car, the report, though really as loud as a cannon, sounds no more than a mere pistol shot, possibly partly owing to the greater rarity of the air, but chiefly because the sound, having no background to reflect it, simply spends itself in the air. Then, always and under all conditions of atmosphere soever, there ensues absolute silence until the time for the echo back from earth has fully elapsed, when a deafening outburst of thunder rises from below, rolling on often for more than half a minute. Two noteworthy facts, at least, the writer has established from a very large number of trials: first, that the theory of aerial echoes thrown back from empty space, which physicists have held to exist constantly, and to be part of the cause of thunder, will have to be abandoned; and, secondly, that from some cause yet to be fully explained the echo back from the earth is always behind its time.

But balloons have revealed further suggestive facts with regard to sound, and more particularly with regard to the varying acoustic properties of the air. It is a familiar experience how distant sounds will come and go, rising and falling, often being wafted over extraordinary distances, and again failing altogether, or sometimes being lost at near range, but appearing in strength further away. A free balloon, moving in the profound silence of the upper air, becomes an admirable sound observatory. It may be clearly detected that in certain conditions of atmosphere, at least, there are what may be conceived to be aerial sound channels, through which sounds are ,momentarily conveyed with abnormal intensity. This phenomenon does but serve to give an intelligible presentment of the unseen conditions existing in the realm of air.

It would be reasonable to suppose that were an eye so constituted as to be able to see, say, cumulus masses of warmer air, strata mottled with traces of other gases, and beds of invisible matter in suspension, one might suppose that what we deem the clearest sky would then appear flecked with forms as many and various as the clouds that adorn our summer heavens.

But there is matter in suspension in the atmosphere which is very far from invisible, and which in the case of large towns is very commonly lying in thick strata overhead, stopping back the sunlight, and forming the nucleus round which noisome fogs may form. Experimenting with suitable apparatus, the writer has found on a still afternoon in May, at 2,000 feet above Kingston in Surrey, that the air was charged far more heavily with dust than that of the London streets the next day; and, again, at half a mile above the city in the month of August last dust, much of it being of a gross and even fibrous nature, was far more abundant than on grass enclosures in the town during the forenoon of the day following.

An attempt has been made to include England in a series of international balloon ascents arranged expressly for the purpose of taking simultaneous observations at a large number of stations over Europe, by which means it is hoped that much fresh knowledge will be forthcoming with respect to the constitution of the atmosphere up to the highest levels accessible by balloons manned and unmanned. It is very much to be regretted that in the case of England the attempt here spoken of has rested entirely on private enterprise. First and foremost in personal liberality and the work of organisation must be mentioned Mr. P. Y. Alexander, whose zeal in the progress of aeronautics is second to none in this country. Twice through his efforts England has been represented in the important work for which Continental nations have no difficulty in obtaining public grants. The first occasion was on November 8th, 1900, when the writer was privileged to occupy a seat in the balloon furnished by Mr. Alexander, and equipped with the most modern type of instruments. It was a stormy and fast voyage from the Crystal Palace to Halstead, in Essex, 48 miles in 40 minutes. Simultaneously with this, Mr. Alexander dismissed an unmanned balloon from Bath, which ascended 8,000 feet, and landed at Cricklade. Other balloons which took part in the combined experiment were two from Paris, three from Chalais Meudon, three from Strasburg, two from Vienna, two from Berlin, and two from St. Petersburg.

The section of our countrymen specially interested in aeronautics–a growing community–is represented by the Aeronautical Society, formed in 1865, with the Duke of Argyll for president, and for thirty years under the most energetic management of Mr. F. W. Brearey, succeeding whom as hon. secs. have been Major Baden-Powell and Mr. Eric S. Bruce. Mr. Brearey was one of the most successful inventors of flying models. Mr. Chanute, speaking as President of the American Society of Civil Engineers, paid him a high and well-deserved compliment in saying that it was through his influence that aerial navigation had been cleared of much rubbish and placed upon a scientific and firm basis.

Another community devoting itself to the pursuit of balloon trips and matters aeronautical generally is the newly-formed Aero Club, of whom one of the most prominent and energetic members is the Hon. C. S. Rolls.

It had been announced that M. Santos-Dumont would bring an air ship to England, and during the summer of the present year would give exhibitions of its capability. It was even rumoured that he might circle round St. Paul’s and accomplish other aerial feats unknown in England. The promise was fulfilled so far as bringing the air ship to England was concerned, for one of his vessels which had seen service was deposited at the Crystal Palace. In some mysterious manner, however, never sufficiently made clear to the public, this machine was one morning found damaged, and M. Santos-Dumont has withdrawn from his proposed engagements.

In thus doing he left the field open to one of our own countrymen, who, in his first attempt at flight with an air ship of his own invention and construction, has proved himself no unworthy rival of the wealthy young Brazilian.

Mr. Stanley Spencer, in a very brief space of time, designed and built completely in the workshops of the firm an elongated motor balloon, 75 feet long by 20 feet diameter, worked by a screw and petrol motor. This motor is placed in the prow, 25 feet away from, and in front of, the safety valve, by which precaution any danger of igniting the escaping gas is avoided. Should, however, a collapse of the machine arise from any cause, there is an arrangement for throwing the balloon into the form of a parachute. Further, there is provided means for admitting air at will into the balloon, by which the necessity for much ballast is obviated.

Mr. Spencer having filled the balloon with pure hydrogen, made his first trial with this machine late in an evening at the end of June. The performance of the vessel is thus described in the Westminster Gazette:–“The huge balloon filled slowly, so that the light was rapidly failing when at last the doors of the big shed slid open and the ship was brought carefully out, her motor started, and her maiden voyage commenced. With Mr. Stanley Spencer in the car, she sailed gracefully down the football field, wheeled round in a circle–a small circle, too–and for perhaps a quarter of an hour sailed a tortuous course over the heads of a small but enthusiastic crowd of spectators. The ship was handicapped to some extent by the fact that in their anxiety to make the trial the aeronauts had not waited to inflate it fully, but still it did its work well, answered its helm readily, showed no signs of rolling, and, in short, appeared to give entire satisfaction to everybody concerned–so much so, indeed, that Mr. Stanley Spencer informed the crowd after the ascent that he was quite ready to take up any challenge that M. Santos Dumont might throw down.” Within a few weeks of this his first success Mr. Spencer was able to prove to the world that he had only claimed for his machine what its powers fully justified. On a still September afternoon, ascending alone, he steered his aerial ship in an easy and graceful flight over London, from the Crystal Palace to Harrow.

CHAPTER XXIX. CONCLUSION.

The future development of aerostation is necessarily difficult to forecast. Having reviewed its history from its inception we have to allow that the balloon in itself, as an instrument of aerial locomotion, remains practically only where it was 120 years ago. Nor, in the nature of the case, is this to be wondered at. The wind, which alone guides the balloon, is beyond man’s control, while, as a source of lifting power, a lighter and therefore more suitable gas than hydrogen is not to be found in nature.

It is, however, conceivable that a superior mode of inflation may yet be discovered. Now that the liquefaction of gases has become an accomplished fact, it seems almost theoretically possible that a balloonist may presently be able to provide himself with an unlimited reserve of potential energy so as to be fitted for travel of indefinite duration. Endowed with increased powers of this nature, the aeronaut could utilise a balloon for voyages of discovery over regions of the earth which bar man’s progress by any other mode of travel. A future Andree, provided with a means of maintaining his gas supply for six weeks, need have no hesitation in laying his course towards the North Pole, being confident that the winds must ultimately waft him to some safe haven. He could, indeed, well afford, having reached the Pole, to descend and build his cairn, or even to stop a week, if he so desired, before continuing on his way.

But it may fairly be claimed for the balloon, even as it now is, that a great and important future is open to it as a means for exploring inaccessible country. It may, indeed, be urged that Andree’s task was, in the very nature of the case, well nigh impracticable, and his unfortunate miscarriage will be used as argument against such a method of exploration. But it must always be remembered that in Andree’s case the rigours of climate which he was compelled to face were the most serious of all obstacles to balloon travel. The extreme cold would not only cause constant shrinkage of the gas, but would entail the deposition of a weight of moisture, if not of snow, upon the surface of the balloon, which must greatly shorten its life.

It would be entirely otherwise if the country it were sought to explore were in lower latitudes, in Australia, or within the vast unknown belt of earth lying nearer the equator. The writer’s scheme for exploring the wholly unknown regions of Arabia is already before the public. The fact, thought to be established by the most experienced aeronauts of old times, and already referred to in these pages, that at some height a strong west wind is to be found blowing with great constancy all round the globe, is in accordance with the view entertained by modern meteorologists. Such a wind, too, may be expected to be a fairly fast wind, the calculation being that, as a general rule, the velocity of currents increases from the ground at the rate of about three miles per hour for each thousand feet of height; thus the chance of a balloon drifting speedily across the breadth of Arabia is a strong one, and, regarded in this light, the distance to be traversed is certainly not excessive, being probably well within the lasting power of such a balloon as that employed by Andree. If, for the sake of gas supply, Aden were chosen for the starting ground, then 1,200 miles E.N.E. would carry the voyager to Muscat; 1,100 miles N.E. by E. would land him at Sohar; while some 800 miles would suffice to take him to the seaboard if his course lay N.E. It must also be borne in mind that the Arabian sun by day, and the heat radiated off the desert by night, would be all in favour of the buoyancy of the balloon.

But there are other persistent winds that, for purposes of exploration, would prove equally serviceable and sure. From time immemorial the dweller on the Nile has been led to regard his river in the light of a benignant deity. If he wished to travel down its course he had but to entrust his vessel to the stream, and this would carry him. If, again, he wished to retrace his course, he had but to raise a sail, and the prevalent wind, conquering the flood, would bear him against the stream. This constant north wind, following the Nile valley, and thence trending still southward towards Uganda, has been regarded as a means to hand well adapted for the exploration of important unsurveyed country by balloon. This scheme has been conceived and elaborated by Major B.F.S. Baden-Powell, and, so far, the only apparent obstacle in the way has proved the lack of necessary funds.

It will be urged, however, that for purposes of exploration some form of dirigible balloon is desirable, and we have already had proof that where it is not sought to combat winds strongly opposed to their course such air ships as Santos-Dumont or Messrs. Spencer have already constructed acquit themselves well; and it requires no stretch of imagination to conceive that before the present century is closed many great gaps in the map of the world will have been filled in by aerial survey.

But, leaving the balloon to its proper function, we turn to the flying machine properly so called with more sanguine hopes of seeing the real conquest of the air achieved. It was as it were but yesterday when the air ship, unhampered by huge globes of gas, and controlled by mechanical means alone, was first fairly tried, yet it is already considered by those best able to judge that its ultimate success is assured.

This success rests now solely in the hands of the mechanical engineer. He must, and surely can, build the ship of such strength that some essential part does not at the critical moment break down or carry away. He may have to improve his motive power, and here, again, we do not doubt his cunning. Motor engines, self-contained and burning liquid fuel, are yet in their infancy, and the extraordinary emulation now existing in their production puts it beyond doubt that every year will see rapid improvement in their efficiency.

We do not expect, nor do we desire, that the world may see the fulfilment of the poet’s dream, “Argosies of magic sails” or “Airy navies grappling in the central blue.” We would not befog our vision of the future with any wild imaginings, seeking, as some have done, to see in the electricity or other hidden power of heaven the means for its subjugation by man; but it is far from unreasonable to hope that but a little while shall pass, and we shall have more perfect and reliable knowledge of the tides and currents in the vast ocean of air, and when that day may have come then it may be claimed that the grand problem of aerial navigation will be already solved.