The Mastery of the Air. A Record of the Achievements of Science in the Realm of Aerial Navigation.

Progress, Volume II, Issue 4, 1 February 1907, Page 120

The Mastery of the Air. A Record of the Achievements of Science in the Realm of Aerial Navigation.

Part I. According to one of the most successful aeronauts of our time, the air has been waiting since the advent of man on the earth to transport airships of his contrivance through boundless space, with the speed and grace of a bird, " in the open firmament of Heaven." This is one of the Brothers Wright, of Dayton, Ohio, who claims that he has discovered the secret of constructing the proper kind of airship. The more famous Santos Dumont makes the same claim. In a contrivance of his own he actually did fly through the air in the open firmament of heaven a distance of 235 yards, in the presence of a large number of spectators, at the rate of some ten yards per second, or 20.5 miles per hour. In a burst of triurhph this aeronaut declared, immediately after his remarkable performance, that he saw his way to building a machine which would fly a hundred miles with as much ease as his present combination of box kites accomplished the few yards of flight which constitute the accepted present record. Dumont has made up his mind that the method of harnessing the air has been discovered and is now waiting only to be developed. He is not alone. A large number of believers are offering prizes for the encouragement of that development. The Daily Mail offers a prize of £10,000 for the first successful flight from London to Manchester, 183 miles ; there is the Archdeacon prize of £2000 for flights of distances over half a mile ; the Pans prize of £10,000 — the offer of the Matin newspaper increased by public subscription to the larger figure — for a flight from London to Paris the prizes of the Adams Motor Manufacturing Company and the A utocav ioumal respectively, of £2000 and £500 to the winner of the Daily Mail prize if the machine or the motorpetrol are made in Britain. In addition, there are the Salomon and Howard de Walden prizes for flying machines of the heavier- than-air type ; the Daily Graphic's prize of £1000 for a flight of more than a mile with one or more human passengers ; and the two Challenge Cups known as the Gordon-Bennett International, and the HedgesButler. These make a substantial aggregate of encouragement. They are not the first offer, however, nor the largest yet made, for there was an offer of §200,000— £40,000— during the St. Louis Exposition, of which $100,000 was for the bes" airship — safe, manageable, and fast. The faith of these believers of the recent past and t ■* pr sent is expressed by the Figaro newspaper in perfervid terms " What a triumph ' A month ag > Santos flew ten yards. A foi tnight ago he flew seventy Yesterday he flew still further and enthusiasm knew no bounds The air is truly conquered Santos has flown Everybody will fly." With all these believers the only questions are • how soon shall we fly, and shall it be with machines that are heavier than air or with those that are lighter '

THE ANTIQLITY OT THE PROBLEM. From the ear.iest ages man has dieamt cf the conquest of the air by boldest flight. In the dawn of history, before the setting of fable Daedalus was believed to have accomplished the feat Shut up in the Island of Crete, where he had constructed for" King Minos the famous Labyrinth, this cunning workman fashioned for himself and his son Icarus each a pair of wings, with which they staited to y over the to a country of safety. The father arrived, but the son, being ambitious, neglected the paternal advice not to approach too near the sun, which would assuredly melt the wax with which his wings were fastened to his body, soared aloft, and met the fate against which he had been warned. Succeeding ages have forgotten the part of the story referring to the successful flight of the sire, preferring to perpetuate the

second as a warning against the ambition which le ds men to attempt great enterprises without cons denng adequately the strength they possess or the means they should provide for carrying them out. Throughout the ages that have succeeded Icarus has furnished the point for every tale of vaulting ambition that overleaped itself. Practical people explained the story of the flying, which they saw to be unthinkable, by substitution , they pointed to the fact that in the days of Daedalus the art of sailing over the water was as unknown as that of fiyug through the air , they declared that the great inventor invented the sail, applied it to the nearest canoe and got away in safety, losing his son < n the voyage by some accident, which in the first sailing voyage on record was not by any means difficult to imagine. Daedalus was the great builder and architect of his time ; the creator he was of the two arts, the lahentor of the fame of all the artists who had preceded him, but for lack of records had been forgotten He was credited with the making of everything wonderful known in his day. All statues of the gods of special excellence were called by his name — Daedala — nothing was regarded as impossible to him In time the myth of the wings was resolved into the fact of the sail ; and the name of Icarus remained alone of the story for the encouragement of inventors to keep on the right track They needed some encouragement of the practical kind. Antiquity and the Middle Ages are full of their endeavours to solve the problem of the air. From Archytas of Tarentum to the great Leonardo da Vinci some of the greatest intellects of mankind were devoted to the solution of this fascinating problem of nymg through the air The first named, who was eminent as geometrician and astronomer, was famous also throughout antiquity for the flying pigeon which he constructed, which probably was

some kind ot kite flown with a string. Which lemmds us that he amusement of flying kites was not unknown to the ancients. In addition, there were many who said they had seen men fly with wings of their own construction through the air But in the absence of information there can be no discussion of their testimony, and the only possibility is that something of the principle of tne p irachute must have been suspected by those who had watched the leaps ot the flying squirrel, which have in our day been measured up to forty feet. But t ey could not have made much progress, for so late as the seventeenth century there is the instance of an exhibitor who, descending from a great height in a machine much like a parachute of our time, broke his leg by falling into a barge moored on the Seine As he did not seem to have any conception of the area of parachute required to sustain his weight it is right to conclude that all his predecessors in the flying art were no better off for scientific equipment. By the time of this adventurer the only persons who were supposed to ride through the air were the witches, who were popularly thought to use broom sticks. But this scarcely belongs to the subject of airships Leonardo da Vinci, painter, poet philosopher and man of science, was conspicuous among his contemporaries for the zeal with which he devoted himself to the art of flying Drawings are extant of a contrivance which kept him employed for many years, a contrivance by wl ich a man exerting the muscles of his legs might keep a pair ot great wings in motion It was the dream ot this great man's life that one day his invention would enable men to fly like the birds through space at his will But neither he nor the large

number of persons who thought and hoped with him were learned enough in comparative anatomy to know that the superior muscular power of birds in proportion to their weight makes easy to them the problem of flight, which to man is impossible with his inferior muscular apportionment. Some of the inventors of that time, moreover, and indeed of other periods of history, were not always remarkable for proper study of means to ends. Like the artists who illustrated their ideas, they were more concerned with the magnificence of results than with the methods of producing them. There is, for instance, the project of Lara the Portuguese, (in 1670), whose proposal to build a flying-machine made him a conspicuous figure in the annals of his time. He designed a boat to be supported by four copper balls. Some gas lighter than air was to be put into these, which, thus charged, would infallibly raise the whole fabric aloft to any altitude. The diameter of these cups was to be 25 feet. But the metal employed in their construction was to be only one two-hundredth part of an inch thick. Had this genius proceeded from theoretical proposal to actual practice, his project would have had short shift, for the balls, long before the exhaustion of air in them, would have collapsed with unsatisfactory completeness. So it was with most of the inventors who were ready with the lightest hearts to undertake aerial voyages on the provocation of their ill-furnished brains. They have their place in history, however, which consists of a name merely, but little more. About Lara there is the additional distinction that he was the first to conceive the notion of getting some gas lighter than air to do the raising and sustaining required for flight through the air. His machine was wrong but his idea was right. Though the first balloon did not rise for a century after his death he was the first to evoke the idea of the balloon The attempts of man to master the air as birds do in their flight, is divided into two pirts- the part which relates to machines that are lighter than air, and that which relates to those that are heavier At the head of the former the name of Francis Lara is entitled to an honoured place

LIGHTER THAN AIR. THE BALLOON PERIOD. In the year 1783, the brothers Montgolfier gave the thoughts of inventors a new turn by their success in elevating a balloon in the air. Papermakers at Annoncay were in a position to experiment with the idea propounded by Guzman and others that if an envelope could be found for enclosing a given quantity of a gas lighter than air the envelope would rise up in the air, and the problem of flying would be solved. They turned their attention to the subject, and after various experiments managed to make a bag of paper and linen of considerable strength, and impervious to air This they contrived to get filled with air heated over a straw fire, and the heated air, being lighter, carried the envelope high up into the atmosphere, to the great wonder of a large crowd of spectators. As the air cooled, the envelope descended gradually, finding its way back to earth without shock or trouble. The brothers soon constructed a balloon of 105 feet in diameter, and the name of Montgolfier became for ever famous in connection with the art of sailing ships through the air Their balloon is number 1 of our next plate It carried no passenger or crew loomed large, rose mysteiiously, floated about majestically, and returned to earth comfortably. Speculation and experiment followed in its track with eager enterprise The first balloon was accepted as evidence of the fact that the work of ascension and suspension had at last become possible. One halt of the problem of flying was therefore solved. The solution of the other half, the propelling and direction, would be only a matter of time. Let it be understood however that though the Montgolfiers had solved the problem of the application, the idea was not thens It was Guzman, of Lisbon who had suggested that heated air might be of use

to the seekers of the secret of aerial navigation In 1760 Cavendish discovered the properties of hydrogen, inter aha the superior lightness ot that gas, and soon after him Black of Edinbuigh suggested the plan of making an envelope to enclose any gas lighter than the atmospheric an This suggestion reminds one of the idea put forward b\ Lai a in 1670 Whether it was taken fiom him or originally hit upon is a question which probably will never be settled Its settlement however at this petiod of the navigation ot the air is immaterial It is enough for all purposes that the brothers Montgolfier flew the first balloon That balloon carried a sheep, a duck, and a cock These were the first aeronauts, and they came safely back to Mother Earth Two months after the first ascent, the chemist Charles conceived the notion of substituting hydrogen gas for the heated air of the Montgolfier process The obvious advantage was that hydrogen did not like hot air, depend upon a fire to keep it up to the mark as a lifter Charles had some trouble in getting the gas into his balloon but after a little difficult\ lie succeeded and the first balloon supported b\ hydrogen went up near Pans remaining in the air for three quarters of an hour On reaching the earth the fabric was torn to pieces by the affrighted peasantry This if it does not confirm the story (now considerably doubted) of Anrlree's fate in 1898, namely that he was murdered with his companions on alighting by some superstitious natives — Esquimaux, Laplanders, Yakoots inhabitants of some part of the nm of the frozen world —

at all events gives it an air of probability The balloon of the chemist Charles was made by the brothers Robert In November, «i month later, Zambeccan discovered the advantages of oiled silk as an envelope tor the lighter gas, and since then all balloons have been constructed of that material Soon aftei the nev\ departure Zambeccan sent up a balloon which crossed the English Channel from Sandwich to the neighbourhood of Ostend, but there was nobody on board Hydrogen eventually took the place of heated air The latter was of course relied on for some little time The first human aeionaut, J Tytler ascended in a balloon inflated by heated air carr>ing the means of keeping the same hot The unfortunate Pilatre dcs Rosiers did the same thing, flying over Pans on December Ist, 1784, after ascending from Versailles Limardi followed quickly with a hydrogen balloon The rival aeronaut compromised in the struggle of the elements, and ascended with two balloons, one above the other one filled with hydrogen the other with heated air Unfortunately something going wrong with the upper balloon the gas escaped, and the fire not being alight for expanding the air of the lower balloon the whole fabric came to the ground with a sickening thud from a height of 700 feet Hydrogen after this disaster displaced its rival Before his untimely death Rosiers had flown thirt} leagues in his balloon establishing a record which the aeronauts of the day made it the obiect of their lives to beat In 1787 Blanchard crossed the Channel in a balloon, and the art of managing

balloons had begun to be fairly well understood A valve at the top of the balloon worked from the car sundry bags of ballast, and an open throat were the indispensables — the hrst for lowering by letting out gas, the second for raising by throwing weight overboard, the third for preventing the expansion of the gas at the higher altitudes from bursting the balloon The last precaution was suggested by the fate of several aeronauts whose balloons had collapsed over them after bursting from this cause In 1821 the celebrated English aeronaut, Mr Green, substituted coal gas for hydrogen, and many used it after his example. But the other gas has never gone out of use in consequence In 1830 Green travelled from London to Weilburg in Nassau in his balloon, a distance of 500 miles, and was considered very lucky to have got safely to that place. For it was well understood that the big round balloon was unwieldy, unsteerable, entirely at the mercy of the wind and not too safe in rough weather The type of that balloon is seen in figure 9 in the illustration The balloon was however, used for many purposes and no car was ever considered complete without a set of observmg-instruments The atmosphere was tested and studied at every possible altitude, and under every manageable condition Humboldt was an indefatigable observer, and the names of the most famous aeronauts were Glaisher, Coxwell Croce-Spmelh, Nadar, Godwin and the American Wise, Fissandier, Giffard, and Dupuy de Lome Of these the American Wise flew from St Louis to Jefferson, a distance of 1159 miles He conceived a project for crossing the Atlantic but fortunately for himself it came to nothing Tt was early in the history that the aeronauts discovered the difficulties of the upper air. Mention has been made of the expansion of the gas at those heights The knowledge of the effect of the atmosphere on the human constitution followed speedily. Balloons ascended to heights up to 31,500 feet Breathing proved difficult, the faces of the aeronauts grew purple, insensibility often occurred, and on one occasion of three men who went up to a height of over 25,000 feet, all became unconscious and two died This type of balloon is in use to the present day Every war office has numbers of them for purposes of observation, many aeronauts keep them for show purposes, descending from them in parachutes,* giving displays on various public occasions, putting them to a vanet\ of uses The only conspicuously serious purpose to which one of the type was put in later years was the purpose of making Andree s attempt on the North Pole This famous aeronaut had invented a system of steering the balloon by a system of drag ropes which he had experimented with in several journeys over the Baltic, all with much success He be lieved implicitly in the system But his fate contributed greatly to the encouragement of the reaction that had set in so far back as the early fifties against the round type of balloon, whose dements the aeronauts had found such abundant reason for being displeased with, reasons chiefly of unwieldiness and unsafety. One of the earliest proposals for getting over the steering difficulty was that of the Greek Stagapoulos who suggested harnessing birds to the sides ot balloons to drag them through the air He did not go into any details to show how r these novel teams could be driven as well as those which drew the renowned chariots of Venus and Queen Mab, but in the drawing which he made they seem to be doing their work fairly well Giffard — of Injector fame — was the first to devote serious attention to the much desired improvement In 1852 he elongated the shape of the balloon, making it elliptical instead of spherical constructed an example 144 feet long lv 3ft feet in diameter, fitted it with a rudder, installed a propeller and a motor, (steam) of three horse power, the weight of the motor apparatus being 4(>2 lbs In this he ascended from Pans and, the weather being calm managed to work up to a speed of between six and seven miles an hour having his balloon under some sort of command He was followed in 1872 by Dupuy de Lome Chiel Constructor of the French Nayy — a service which has always been in the van of enterprise — with a machine worked by man power taking up on the occasion of his ascent from Pans twelve men for operating the motor. The machine was 1 18 feet long by 4^ feet in diameter, and he had a success d'esiime He preferred man power, having a wholesome dread of a fiery motor working in close proximity to the hydrogen in the balloon The man power not proving economical others turned to steam, amongst them Wolfert and De Bradski who thought they could take sufficient precautions against the danger feared by their predecessor But they failed, and they lost their lives in full view of Paris Tissandier came next, in 1883 with a "Dirigible " (see figure 2) which accomplished the best

* Baldwin in 1887 descended a mile in 3i minutes with a parachute

results hitherto attained. The ■; machine^ (cigar shaped) was 90 feet long with a diameter of 29, it carried a rudder of unvarnished silk, a propeller 9 feet long, and an electric motor — the whole fabric, with stores, motor, and aeronauts, weighing 2650 lbs It managed to make seven miles against a head wind and did not manage to make any further appearance, as (so it was thought at the time) the flight had revealed some structural defects of radical character. Proceeding on the lines followed by his predecessors Giffard, Dupuy de Lome, and Tissancher, Captain Renard, of the French army, chief of the balloon department of the service, reached high water mark of that day with his celebrated "dirigible" balloon La France. In his ascent he was accompanied by his assistant Captain Krebs of the same service. His machine was more like a cigar than any of its forerunners (see hgure 3 ), it carried its propeller in front and its motor was electric, of greater power than Tissandier's The ascent was made in June 1885 Here is the account published of the same by the Tunes. " The balloon was of elliptical form and carried an electric motor, a screw and a rudder, the motive power being derived from electrical accumulators which could supply during four hours a power of ten horses. These worked the screw which served as a propeller to the apparatus. The balloon was made of light strong silk, and was covered as usual with a netting to which the car was suspended All the propelling mechanism was contained within the car, the rudder alone projecting outside like that of a boat. The car was mounted by Captain Renard, Director of the Balloon Works, and by his assistant, Captain Krebs, both engineer ofneers. On being released from the earth the balloon at once rose to a height of about 180 feet and, urged by the swift rotary movement of the screw, made a straight course for the Hermitage of Villebon, about seven miles distant as the crow flies A wind was moving against it at a speed of 18 feet per second. Captain Renard worked the propeller, Captain Krebs steered Villebon had been fixed upon as the goal of the journey, and when this place was reached Captain Krebs waved a flag as a signal that he was going to turn. The spectators were then amazed and delighted to see the balloon gracefully describe a curve of 300 metres radius and sail back to Meudon. On approaching the lawn from which the ascent had been made, the balloon descended in an oblique direction and with a steady motion, showing the engine \as completely under control Within twenty feet ot the ground the machine was eased and a rope being thrown out from the car, the balloon was hauled down and touched the earth without the slightest shock. The whole journey had occupied about forty minutes. From this account it is clear that the balloon La France had attained a speed of 21 miles an hour half of the course against a wind of 12J miles The feat caused great enthusiasm throughout the world The United States government at once commissioned fhayer, the well known aeronaut, to build 3 " dirigible " double the size, carrying double the power. The theory was simple enough It was in fact thought to be a mere question of proportion a question of lifting power. Double the lifting power, and you doubled the power camable. The orders to Thayer therefore were to build a balloon of a diameter of 60 feet with an ascending force of 70 tons, driven by compressed air A speed of 40 miles an hour was confidently expected as the result. The machine was designed according to instructions, but never built. The trouble was that Captain Renard ascertained by further experiments with La France that the machine was absolutely unmanageable m a heavy wind and nearly so in a moderately brisk breeze The French War Office built another and larger machine nearly double the size It had a motor of gasoline of 50 h.p., was said to be exceptionally manageable and altogether great things were mysteriously predicted of it on its first appearance, which would not be till the outbreak of war Then the Germans, all the critics declared, would understand the meaning of La Revanche But this redoubtable machine was never taken out into the light of day and has not been heard of for years. Since the last appearance of Captain Renard 's navigable airship there have been many, and in the hands of enthusiastic devotees But they have never, in spite of the encouragement of prize offerings enough to stimulate the dreams of avarice, advanced beyond the efficiency achieved by La Trance Her best factor of control and stability was the front propeller, and that has been followed in all the copies Renard himself, now a colonel disgusted by the demonstrations of weakness in the balloon principle of construction, has long been one of the most strmgest supporters of the system of aviation His contemporaries remained, however, staunch to the pnnciple of aerial navigation on behalf of which he had led the way with <uch hipfh hopes

By the end of the last century a host of aeronauts was competing for the lead Invention succeeded invention and trial succeeded trial The scientific journals gave great space to the chronicle of their doings, prizes were offered to stimulate their enterprise, every war office was busy and the number of aero-clubs multiplied In the first year cf the present century Count Zeppelin, of the German army, made his great effort He had headed the famous cavalry raid which opened the campaign of 1870/71 he was determined to wrest from the same enemy the empire of the air won by the efforts of Renard and the m\stenous invention that was alleged to have followed them The Kaiser looked on with approval, saying in his magnificent way that the Count had revolutionised the art of ballooning The Count's airship was built in a floating house on Lake Constance It was 420 feet long with a diameter of 28 feet , it was covered with a network of aluminium, its material was water-tight Dergamoid above, and light silk below Fashioned in cigar shape, it was divided into seventeen cojipartments, each carrying its own separate gas supply Suspended was a gangway nearly the length of the fabric, carrying two aluminium cars, each furnished with benzine motor of 10 lip with oil tanks and water ballast There were two aero propellers at the sides of the machine about the centre a rudder and a running weight for keeping the balance On the day the ship was brought out of its house it had cost the inventor and the ascent that followed cost him more. On that day, in the presence of a large crowd of spectators, the maiestic fabric rose into the air and w a'J very soon in difficulties The steering apparatus fouled one of the propellers the breakdown of a winch paralysed the running weight, and the power was found to be not nearly enough Nevertheless, after sailing some four miles, on a fairly straight course, the ship came safely to land, and as she was taken back to the floating house there were many congratulations and as many prophecies

of her future greatness But she never left that house again The trip had revealed structural defects of radical character. Attempts were made to raise funds, as the inventor's means were exhausted, but without avail , the business of investing in airships having come to be regarded as risky. The Zeppelin airship was never heard ot more, and the only subsequent news that concerned her in any way was the announcement ot her patriotic proprietor's bankruptcy. A host of rivals was m the field, the patent offices of Europe and America were busy, and men began to seriously consider whether after all they were not destined to fly, in machines ot cunning construction. Conspicuous among the crowd of aeronauts was Santos Dumont, the young and enterprising Brazilian He appeared first in the front in the same year that witnessed the failure of Zeppelin with a cigar-shaped balloon supporting a spar on which he rode after the manner of a cyclist Machine after machine did he construct until he astonished the world by flying round the Eiffel Tower and winning the Deutsch prize of £4000 He had a gasoline motor developing great power with veiy light weight a thing which seemed to realise the mechanical aspiration of " a horse-power in a watch case " and he did the distance — 3^ miles and back — m half an hour The world applauded him wildly, but he fell short of the record of Renard by t\\ o miles an hour, and he only flew half the French soldier's distance, and in subsequent efforts he had many dangerous accidents. Encouraged by the plaudits of the public of many countries he went on building on the same lines, until he was announced as a competitor for the prize offered by the authorities of the St Louis Exhibition for the best airship. He was to compete in a vessel 165 feet long by 27 feet of diameter, with a motive power ot dO hor=es This inventor was the theme of much comment at this time People seemed to thmk him capable of any feat, no matter how extraordinary He had said one authority, a very handy machine, lust the thing foi paying visits in 50 feet b\ 18 of 3h p and a speed of 10 miles an houi ram or «hine ; he was building his great omnibus an ship 157 feet by 28 he would carry a load of passengers with regularity and despatch and he would charge them by weight These and other stories went round about the young man, while he steadih plugged away at his calling In the crowd of his rivals the brothers Lebaud\ took a high place with a balloon dirigible of the inevitable cigar-shape, 185 feet by 32, driven by a 40-h p gasoline motor which, having beaten the Santos Dumont record was taken up b} the French war office, ever on the look-out for novelties of promising character The names of the rest were legion, and all were sailing airships of the old pattern which Renard had brought to a condition not seriously surpassed b\ any of his successors The new types were better framed they had very much better motors, and had attained nearer to permanency ot rigidity — the quality for lack of which balloons become flabby and refuse to «teer — but they were totally unmanageable m anything like a " breeze " The papers were full of the doings and intentions of the Marquis de Dion, of Me=srs Pillet, Robert, Girardet, Boisset, Bour gom, Francois and a host of others. Nor was England behind The honour of the flag was supported by Spencer with a machine 93 by 24 with a power of 24 horses, by Beedle with one of the same dimensions and half the power, and b\ the veteran experimenter of twenty-five years Dr.

Baiton, with a monster 170 by 40, carrying three motors of 50 h.p apiece In America the names of Baldwin, Langley, Bell and the brothers Wright towered above the crowd The four last were, however, aviators A description of the Barton air-ship is necessary, for it differed from the rest in the remarkable respect that it was designed on both the principles of aeionautics, combining the two, which had been kept separate by the inventors up to this time Barton's machine was fitted with aeroplanes as well as the gas bag of large size common to all the rest He had experimented with two models in 1899, one on the accepted principle of Renard, the other with the aeroplane exclusively, and had found them both deficient Profiting by the experience thus gained, he devised a third machine combining the two Constructing a fourth still of the model slze the respectable size of 35 feet in length — he made some experiments in the open Ihose he had previously made under the cover of the Public Hall at Beckenham answeied extremely well, the machine rising and tailing without an> expenditure of gas, and obeying its rudder and keeping direction with good line But experiments under such conditions being inconclusive, as every inventor knows by this time, he arranged a trial m the open Unfortunately the clock-work motor was not powerful enough. Still, the results obtained were encouraging Although there was but little hftmg-power in the balloon, the action of the aeroplanes caused it to ascend as it gathered way, and in ten minutes it had reached an altitude estimated by onlookers at 800 to 1000 feet it kept perfectly level, and steered well according to the set given to the rudder, nearly at right angles to the wind After going thus for about three miles the clock-work power ceased to act and the machine sailed on for another half-mile

turning round and round after the manner of the ordinary round balloon, and came safely and quietly to earth Acting on the experience thus gained, Dr Barton called m the best ballooning experts, and with their aid designed a full-sized complete airship. (See figure ) The balloon or sustaining part is designed in the form of a cigar, the largest diameter being about two-fifths from the front end, and was 180 feet long by 41 feet maximum diameter This gives a total" lifting capacity of 144,000 cubic feet or 10,080 lbs. The total capacity was 150,000 But a special chamber was reserved for air as will be seen presently, at a capacity of 12 000 Ordinary balloons filled with very carefully made hydrogen gas will lift 1200 grammes per cubic metre but It is not safe to calculate upon more than 1000, as the quality of gas varies so much With coal gas the lift is 730 grammes for a good quality, and 700 for medium It is found in practice that there exists a great necessity for preserving the external shape, especially of a cigar-shaped balloon as has been practically demonstrated lately In the balloon now described this difficulty will be greatly reduced, as nc gas is expended for descending purposes, and it may, therefore, leasonably be expected to remain in the air for a \ cry long period The subsidiary balloon is filled with air, so that when the reduction of the pressure from ascension of the airship, or from the heat of the sun's rays causes the gas to expand, the air is driven out ; and on the gas again contracting air is pumped in This plan has been, of course, used by many experimenters, the latest of whom is M Santos Dumont, who once got a bad fall because his air-pump broke down, the material buckled and the balloon collapsed. The entire uppei surface of the balloon proper is enveloped in an extra casing or chemise provided with cane stifteners

From this chemise the cai and its superstructure are suspended — the suspending cords are not shown The superstructure is made of steel, mostly of tubular section, and is constructed to carry the propellers, aeroplanes, and rudder. The ship is to be propelled by six two-bladed triple fans three on each side of the superstructure It will be observed each pair of fans is centred on a different plane to the others, in order that each shall revolve and pass through different air The balloon is protected from the fans by network screens. Each pair of fans will be driven by an oil motor, with e'ectnc ignition each motoi exercising 45 bh p Experiments recently earned out at Mr. Alexander's experimental works at Bath show

that a thrust of 25 lbs per brake h p can be obtained without excessive weight However, in this instance, the thrust is taken as 20, giving a total of 2700 lbs for the six fans There are three sets of aeroplanes, each set consisting of three, one over the other, each aeroplane having a rod in front for the pivot and a rod in the rear for raising and lowering the end by means of the links- — as shown in the diagram Fig 2 By means oi these aeroplanes the ship will be raised to any desired altitude above the point to which it would naturally rise by means of the lifting power oi the balloon, and failure of the mechanism can result in nothing more than its returning to its original point, which will be 1000 feet above the ground The deck, on which the crew can freel} walk about, is floored with a light matting and is provided with a hand-iail and netting , the fan motors are fixed to this deck, and in older that the deck shall remain always in a horizontal position a water tank is placed at each end, each tank containing about 50 gallons of watei which is kept, by means of a pump and connecting pipes, in a constant state of circulation There is also a pendulum-operated valve arranged so that, should one end of the deck drop, the pendulum shuts off the water from the lower end and pumps it to the upper tank till the level of the deck i^ restored The weight of the whole including a crew of five men, was 9600 lbs with a maximum aiea of balloon of 1320 square feet \s to the efficiency of the power, the inventor was very emphatic He said that according to Dr Smeaton's experiments the air resistance of a flat surface at 13 miles an hour is just under one pound per square foot, while the moie recent experiments ot Profe^soi Langle\ the famous aeronautical authority, (since venfied by others of competent character) show

that amount to be excessive. This pressure is of course largely reduced if the object piercing the wind is in the form of a cone, in which case the resistance is variously given as from one-third to one-fifth of that of a flat surface. Now allowing only a third for reduction for the change of shape to the conical, the resistance offered by the balloon will be under 450 lbs to a wind of 13 miles an hour. To this add the resistance of the aeroplanes, superstructures, car and contents, and the surface triction of the sides of the balloon, say 250 lbs., and we have a total resistance of under 700 lbs. But the thrust available was estimated at 2700 lbs., therefore it was not unreasonable to expect a speed exceeding 20 miles an hour. This apparently fair conclusion was supported by the experience of those present at tht trial of Dr. Schwartz s aluminium balloon, which (before the first driving belt came off — a side-light, this, on the insecurity of the balloon race) had advanced steadily against a breeze of 19 miles an hour. That machine, however, had only a 12-h.p. motor, and was of about the same weight and dimensions with a capacity of 130,500 cubic feet, 13,500 less only than the Barton balloon It was understood at the time that, should the Barton achieve in practice the estimated results, it would be purchased by the British government for war purposes. The talk about this venture considerably increased the interest taken by the ballooning world in the great trial arranged by the authorities of the Louisianian Exhibition Much was expected in the way of result. One hundred thousand dollars were offered as the first prize for the best airship flying a certain distance over an indicated course at a rate of not less than 20 miles an hour over the ground, which meant a rate of not less than 25 through the air. Fifty thousand dollars were to be divided in prizes for the victors, in certain contests between rival machines, and the balance of the offer of 200,000 dollars was devoted to the expenses of the exhibition and trials. The newspapers prepared the public to expect a great competition by publishing accounts of successful attempts of various inventors, and to enjoy the view of marvellous craft sailing at will under perfect control in sight in every part of the firmament of heaven. At one time it was announced on what appeared to be good authority that 92 competitors had entered for the big event But as the day approached the public began to see that its expectations would not be realised The fact is that as soon as the aeronautic world realised that the trials were to be less experimental than practical the conditions comprising a prescribed course the execution of

certain named evolutions, the attainment of a certain rate of speed and the return to the starting point within a specified time, tfie entries fell oft. A panic set in among the inventors , the panic grew, and when the day came for the big event not one inventor qualified Not even the ship of the famous Barton described above, or the bombastically heralded craft of Santos Dumont The former did not go to St. Louis at all. The latter arrived and was found quarters duly, in accordance with the desire of its spirited inventor, who had been the very first to signify his intention of competing But at the last moment some vandal succeeded in getting into the aerodome where the Dumont material was lying, unpacked, and slashed the gas bag so badly that it could not be repaired in time for the trial Detectives were called m and a thorough investigation was made with no other result than a general suspicion that the general panic had included Santos himself, who had therefore either slashed the gas bag himself or instructed some one else to do so, in order that he might avoid the embarrassment of a failure It was a suspicion natural enough as suspicions go. It may have been absolutely without foundation, as suspicions often are. But when the baffled aeronaut made no attempt to repair damages, and took himself and his machine back to Pans by first opportunity there were not wanting those who saw abundant confirmation of suspicion Only four exhibitors made an appearance, and it was only a factitious one, not for the prize for

the best airship, which prize they felt they could not win, but arranged merely for pleasing the disappointed public These were Baldwin, Berry, Benbow, and Francois. The last had a monster balloon with a motor of 24 h,p and a great pair of propellers, and from this machine's periormances the spectators expected much instruction. It was filled with gas only after very great difficulty, but when the hour came for cutting clear, the inventor's confidence evaporated and he declined to give the order. The balloon was described as behaving thenceforth like a hamstrung elephant On the other hand the airship of Baldwin was fairly successful, inasmuch as it made several ascensions under the direction of its "chauffeur" (if we may use the term), Knabeshuh who accomplished the feat several times of making a wide circle and returning to the balloon enclosure These flights were very interesting " This bold manner of the celestial seas," says the official pccount, " made no provision for his security, but stood upon lateral pieces of gas-pipe composing the framework of the ship, and skilfully directed her movements, exhibiting the most perfect control. By shifting the steering-blade and propeller he was able to ascend or descend at will, and similarly his ship was brought to change its course and to describe a circle, though the vessel was not thus controllable in a wind of more than seven miles an hour " The description added that the grace and beauty of these movements inspired the spectators with prophetic visions of the marvellous future awaiting the p ying people of an enterprising world But the only solid result ol the

great pnze offering was the demonstration of the lutibty of the balloon called Dirigible for practical purposes Despite these poetical effusions the reaction made itself more pronounced than ever By almost universal consent of aeronauts it was determined to return to the school of nature for direction in the art of flying through the air, and take lessons from the birds It was said that the balloon had shown only that a few in\ entors had succeeded in calm weather in wort ing on an angle with the wind and even in travelling to windward, but that they had not demonstrated the practicability of steering apparatus lighter than air under the majority of working conditions presented by the atmosphere The balloon, it must be said for it, had done good work in its day Miniature specimens had penetrated the secrets of the atmosphere to heights above 40,000 feet, bringing back the figures of seltregistenng instruments which had become scientific records Ihose of full size had given such extended opportunities of observations to soldiers that e\ery war office in the world had employed them and spent large sums in the effort to improve their efficiency The Republic of France never can forget the invaluable services of the balloon during the siege of Pans The airships of that memorable time carried the government of the Republic out of the hand of the enemy to organise the defence of the country, and maintained, in spite of vigilant hostile fire, a postal service which kept the beleagured capital

in touch with the world Finally the balloon had participated in the eternal assault on the Noith Pole It had failed as the sailing craft, the steam boat, the sledge and the Esquimaux dog had failed, but it had at any rate pro\ ed itself by itb attempt worthy of the honourable estimation accorded to it b). the world

HEAVIER THAN AIR THE PERIOD OF AVIATION Man has got back to the original plan oi seeking the secret of the air in the flight of the birds thereof The first question is of the bird to be chosen tor the master Shall it be the wide-iangmg albatross, whose majestic flight is but seldom disturbed by the beat of a wing, or the flapping heron 01 the homer pigeon whose pinions never cease from struggling or the swallow, whose dextentj is like the lightning, or the " eagle aloft " soaring in circles "to the blazing sun ' ? The difficulty of choice is accentuated by the uncertainties of science as to the exact nature of the functions of the wing in flight In a general \va> it is well understood that the foiest bird has shoit bioad wings, which enable him to swing round among the timber and the undergrowth, and to rise almost straight upwards to the shelter of the tree tops, whereas the bird of long wing when on level earth or water finds it hard to rise and can only do so at long angles \nother difficulty in the way of the discover\ of the secret of aitificial flight is the difficulty of maintaining equilibrium in practice Of this it has been well said that the air is not like the smooth level floor on which the child learns easily to walk, but is full of various inequalities ever changing

by action of unexpected and unforeseeable currents Man has as much difficulty in getting accustomed to this condition as the child would have in learning to walk on a tumbled and perpetually changing surface JVluch practice is done in many things — skating, riding -walking — in all of -which there are falls But in the air there is only one fall and it gives no experience that can be used A third difficulty is the difficulty of the start. How to rise automatically from the ground in the face of gravity in a machine heavier than air or how to dive as the birds do off a tree bough or the edge of a cliff, finding stability and velocity with immediate success ■\ fourth difficulty concerns the wing Buds use their wings for the double purpose ot sustaining and driving their flight. Ihe wing evidently requires to be of considerable area. But where is the mechanism that will convert so broad a bail into a napping propeller ? Take the wing of the albatross with its long bones and lock joint at the elbow, and its fine feather work at the end opening and shutting at will, and the minute detail of muscles ever efficient for their operation Alan wants such an instrument for his airship if he chooses wings, but the idea of setting about those details on the scale he requires and with the materials at his command is almost unthinkable from the practical point of view. Some difficulties which acted as deterrents in former times were difficulties of ignorance now dispelled It was, for example long held that the bones of birds are, like balloons, hollow and filled with hot air and it was concluded that no other sort of structure could be got to fly It is true that the bones ot birds are hollow , it is also true that the air in them is heated by the muscular exertion of the bird in flight. Michelet, the most charming and, in some respects, most correct ot all the writers on ornithology, takes the view that a bird is a species of hot-air balloon, rising from the ground and supported in flight by means ol hot-air cells in its feathers and bones. To examine this theory, take an albatross weighing 24 lbs., and treat him as of the bulk of a cubic foot — as a matter of fact his bulk is less — and let the whole of this bulk bp one huge hot-air cell \\ hat is the sustaining power ot the enclosed hot air ' \t 60° F it is 40 grains and at 100" it is in' ' But the weight to be sustained is "24 pounds' Ihe hot-air cell theory does not require an}' furthei mention The exaggerated notion of the power required for flight which long prevailed was another stumbling block for the aviator It was taken tor granted that the power to be provided for sustaining bodies must be very great , and thus the difficulty ot the problem was increased by the consideiation that power must be provided for sustaining as well as foi propulsion With this fancy Mr W P Thompson, C E dealt very neatly in the yeai 1881 in a lecture delivered befoie the Liverpool Polytecl me Society He said "Itis a common remark that a body falls at the rate of 16 feet per second, therefore we can easily calculate the power required to keep it m suspension But suppose our smallest measure of time were three seconds In three seconds a body falls 145 feet, or nine times what it does in one A similar calculation on this datum would make the power, necessary to keep a given body suspended, three times as great as w hen calculated by the other datum Therefore if the popular form of calculating this matter be correct, it depends entirely on the quantity of our smallest measure of time what power is exerted in keeping a given weight in the air, w hich is absurd If, indeed, our smallest measure of time had been a period equal to a hundredth part ot a second, half the false theories m regard to the enormous power required for flight would nevei have arisen If a heavy body were allowed to fall for the hundredth part of a second, and then arrested ; then let fall for another hundredth part of a second and then arrested as before , and so on for a hundred times, so that the body should have been free to fall during a series oi periods unitedly equal to one second, it would have onl\ fallen two inches, instead of sixteen ieet, the distance it would have fallen in a single continuous interval of one second If the period of continuity had been the thousandth part of a second, and there had been ten thousand of these periods, the total fall would have been the fiftieth of an inch and the power required to bring it back to its primary position, in other words, the powei required to keep the weight m suspension would only have been the weight multiplied by the fiftieth of fv inch per second instead of by 16 feet pei second as is the usual calculation Going a step furthei and arranging, as in the inclined plane moving at sufficient velocity, that there should be no fall at all in other words, continuous instead of intermitted arrestation, and no power is exerted in keeping the weight in suspension " These demonstrations that bodies which aie not balloons inflated with heated air can fly , and

that it is not necessary to expend any power in keeping them suspended in the air at high velocities, bring the study of the problem of aviation within more reasonable limits. Then there is the saying of Jules Verne of twentyyears ago, that it is not necessary for imitation of bird methods to be servile, as for example locomotives are not copied from hares, nor ships from fish. To the first we have put wheels which are not legs, and to the second screws which are not wings. This idea of the propeller suggested the avoidance of the difficulties of wing construction, and the sailing of the albatross suggested the aeroplane The combination of the two would, it struck many inventors, answer the two-fold purpose of the bird's wing. Moreover, the fact was well understood that the air is highly resistent — a parachute of a yard in diameter in practice not only impeded descent but made it isochronous On the other hand there was the kite, the plaything of generations • men had even crossed rivers, towed over by kites of which they held the strings. Science studied the kite. The result is given by the authority we have already quoted thus —

"In figure I a kite is shown. The ■wind blowing against it m the direction of the horizontal arrow is deflected at the same angle. If then the kite be declined at an angle of 45\ the wind is deflected vertically downwards and the kite forced upwards with equal force. Referring to the diagram (Fig 2) let E F equal the weight of the kite in pounds , B D the force of the wind on the kite in pounds , AB or BF upward force caused by the rebound of the air ; B C direction of string Completing the parallelogram we find an unbalanced power tending to raise the kite ; the kite will therefore rise till the angle DB C , becoming more acute, the quantity B G increases until it and E F

(dead weight of kite) become unitedly equal to B F (or A B), when the kite becomes stationary If, however, the wind lessens, the quantity B A diminishes, and the kite falls till the lessening quantity B G and weight of the kite E F again balance the upward force of the wind A B or B F. We see then as at an angle of 45 the wind is deflected vertically, and therefore gives the most lifting power, the tail ought to be weighted to such a degree as to cause the kite to stand at 45 — that is, heavily in a high, and lightly in a gentle breeze Also that the nearer the thing approaches the horizontal the greater is the lifting power of the kite. " Every one has doubtless played ' ducks and drakes ' (alias throwing flat stones nearly horizontally over the surface of water) and has counted the number of leaps the stones have made before sinking into the water. All skaters, too, are familiar with the fact that a man can skate with impunity over ice that a boy could not stand on without immediately breaking through In each case velocity is a very important item ; the skaters and the stones alike have not time to sink. A kite or plane traversing a stratum of air rapidly is supported in a similar way, not having time to displace each portion of the area traversed before entering a fresh portion

" Suppose a plane (A) slightly inclined moving rapidly in the direction of arrow B (Fig 3), the

wind (arrow C), meeting the under surface of the inclined plane, is diverted downwards (arrow D), displacing the air below But air cannot be suddenly displaced without causing a great resistance, therefore if the plane goes fast enough the air forms an approach to a solid surface, like the water in the case of ' ducks and drakes ' " Now a solid projected through the air should present an edge or point to the air it cleaves, but if the planes of which it is composed have an uniform angle with the perpendicular, it makes little matter how these planes are placed. Thus \, B, C and D (Fig. 4) would have approximately the

same resistance in cleaving the air point first. But A has a tendency to descend, Bto ascend. If therefore we make a combination of these (C) it will be neutral, but it has, independently of its shape, a tendency to descend by force of gravity Let us therefore give a sufficiently great preponderancy to the lower slanting plane to neutralise the gravity, the result being D Now D thus weighed would require almost exactly the force to counteract the resistence of the given speed that A would destitute of weight We thus see that provided that we can alter the shape of the object at pleasure, at a high velocity, the amount of weight within certain limits causes little or no difference to the power required. How strikingly in this point the plane or kite differs as a means of keeping a weight suspended from the voluminous balloon." There remains to consider the difficulty of making a machine rise as the bird rises for his flight. Take the albatross, which has to go some distance along the surface of the water before it gets up m the air How is a machise to be made to follow this examnle ? The question was answered for the thinking by the analogy of the hydroplane 7 hey remembered that long years ago the Canadians constructed boats which did wonderful things on their big lakes ; very strange craft of their invention beating everything that floated without being propelled by other than wind power That craft was called a " skate " It was a boat whose bottom was an inclined plane reduced to about one-third of normal width When sailing the skate showed a tendency to rise near to thf surface of the water, and in strong winds with all sail set she actually did so skimming the water with a minimum of friction which enabled her to leave everything floating miles astern But the skate was, as may well be imagined a very dangerous craft, peculiarly liable to go over The advent of steam did not help matteis, because while it made the craft safer by reason of the absence of sails, it dragged its propeller and therefore lost the superior speed For these reasons the " skate " went out of favour But its principle remains to give hints to the aviators Several of the competitors for pride of place m the invention they are seeking with such ardour have solved the problem of making their machines rise up from eaith by provoking the resistance of the air. The wing difficulty brings another in its train The question of that is raised by the question of the necessary length of the wing An albatross weighing only 24 lbs. has wings about 12 feet from tip to tip Therefore a man weighing 144 lbs ought by analoerv to have wings each 36 feet long or 72 feet in all as shown in the diagram ; and a flying-machine weighing 12 tons to take an extreme case by way of extreme illustration would require an extent of wings' of 2i miles from tip to tip The difficulty has been faced and in one case met by a proposal to supply machines with a row of wings on each side horizontally placed one

behind the other, copying nature in fact after the example of many insects. In support there is also the analogy of the long flights of the migratory birds which arrange their flights so that the birds fly in single file In this case the air compressed by the first wing rebounding upwards forms a firmer cushion for the succeeding one to act upon, until there is set up an advancing wave and an induced current Tne proposers of this expedient, however, admit that some sort of parachute arrangement would be required, capable of expansion, at need "to break the fall " The difficulty is lessened by the further consideration mentioned above that but little power is required after sustaining the body in the air in comparison with the power wanted for propelling at speed. Still as some provision must be made for the sustaining power, after the fashion of the kite, and that provision must bear some relation to the weight to be sustained, the difficulty raised by the length of the wing which acts both as sustamer and parachute is considerable The power required for sustaining is estimated at something like the ninth part of a horse-power lor 10 tons. Still the kite or parachute effect must be attended to. In practice nearly all the recent experimenters in aviation who have got their machines to rise off the ground have found that when they return to earth after their brief flights there is a great and sometimes disastrous tendency to bump. Science has proposed to get over this difficulty by the use of horizontal screws This was the theory on which Jules Verne relied for the support of his renowned " Clipper of the Clouds." Pettigrew, the well-known authority, describes a model which developed later into a favourite toy. It was a plane provided with two vertical axes, each carrying a horizontal screw These screws being set revolving in opposite directions displace quantities of air above the plane, which cause a resistance of the rest of the air in the neighbourhood, forcing the plane upwards. The toy made on this principle was operated by clockwork, which at once set the screws revolving and set up the machine The gradual expenditure of power caused the upward movement to become slower until it ceased, after which the power sufficed to retard the descent till the machine returned without harm to the earth One or two inventors have experimented in this direction. Others have preferred the use of a tail arrangement for the vertical steering In theory such a use of power (the double horizontal screws) would maintain equilibrium without fail and automatically. In practice the pressures from without would have to be taken into account. There are two centres in practice • the centre of gravity and the centre of pressure. The problem that so baffles aeronauts is the problem of reconciling these pressures, so to speak, and keeping them friendly In some thousands of gliding experiments some experimenters have managed to adjust the balance by shifting their own weight in one direction or another as need arose. There were many disasters, and besides, when working on a large practical scale, such adjustment is obviously impossible some mechanical expedient is needed, and it is imperative that it should have automatic action Some inventors of to-day make express admission to that effect These were the devices for overcoming the supposed natural law of the proportionate wing surface, which discouraged invention so greatly by its reduction to the absurd. The true answer, however, was soon found It is that there is no such law. The natural fact, demonstrated by many measurements, is that the greater the creature supported in the air, the smaller the relative supporting force. Mr. Langley, the American experimenter who built a flving-niachme ln 1896 which actually flew over half a mile, collected figures from which he obtained the following approximate results Machine with 54 sq. ft. wing sustained 30 lbs. using 1 i h p Pte-odactyl, extinct flyer, with 25 sq. ft. wing sustained 30 lbs weight, using 0.05 h.p. Condor with 10 sq ft wing sustained 17 lbs. weight, using 0 05 h p Turkey Buzzard with 5 sq ft. wing sustained 5 lbs. weight using 0 15 hp. Pigeon with 0 7 sq ft wing sustained 1 Ib. weight, using 0 012 h p Humming Bird with 0.03 sq. ft wing sustained, 0 02 tb weight, using 0 001 h p On these figures he remarked " particular attention is to be paid to the fact that, regarding the ratios of supporting surface to weight supported, these ratios are not only not the same in all the birds, but themselves differ greatly, but systematically, with the absolute weight " If we enquire how much one horse-power would support for instance supposing the ratios of sustaining surface (i c wing area) to weight to be constant, we find that one horse-power will support in The Machine 20 lbs. with 36 ft. of area or If sq. ft. to the pound.

Wild Goose 34G lbs. with 101 ft of aiea 01 0 20 sq it. to the pound. Pigeon 83 lbs. with 58 ft of area or 0 7 sq ft to the pound. Humming Bird 15 lbs. with 26 ft. or aiea of 1 73 sq. ft. to the pound. assuming the three latter to preserve the same relations on an enlarged scale. So that, broadly speaking, so far as these few examples go, the larger the creature the less relative surface and power needed for its support From the obvious mathematical law that the area of bodies in general increases as the square of the dimensions, while their weight increases as the cube, it is an appreciably plain inference that the larger the creature or machine the less the relative area of support may be (that is if we consider the mathematical relationship without reference to the question whether this diminished support is actually sufficient or not), so that we soon reach a condition where we can not imagine flight possible But this apparently mathematical consequence is not the law of Nature, for while it is found that in the larger bird a smaller area for each pound of the weight is given under the law than in the smaller bird, it is also found (what is another thing) that this smaller area is nevertheless sufficient, and that from the mathematical law just cited there does not follow the apparently obvious consequence (notable in the larger creatures like the condor, perhaps less notably m such a creature as the pterodactyl) that the bird cannot be supported While the fact is certain, the cause does not s em too clearly known. This anomaly was first noticed by M Lucy a French observer in 1868, whose tables may well be quoted in support of the above conclusion Square feet of wing surface per pound of weight Insects. Gnat .. •• .49 Dragon Fly . . • - 30 00 Ladybird ' . . . . . . 26 60 Dragon Fly (common) . . 21 60 Tipula (Daddy Longlegs) 14 50 Bee . . . . • • 5 25 Meat Fly . . • 5 60 Drone . . • 5 08 Cockchafer . 5 15 Stag Beetle (female) 4 66 Stag Beetle (Male) . . 3 75 Rhinoceros Beetle . . . 3 14 Birds. Swallow . . • . 4 82 Sparrow . . 2 72 Turtle Dove . . . . . 213 Pigeon • • 1 25

placed the apparatus to be tested and, among other things, this included surfaces disposed like wings which a ere hung from the end of the arm and dragged through the air till its resistance supported them as a kite is supported by the wind One of the first things observed was that if it took a certain strain to sustain a properlydisposed weight while it was stationary in the air, then not only to suspend it but to advance it rapidly at the same time took less strain than in the first case A. plate of brass weighing one pound, foi instance was hung from the end of the arm by a spring which w^as drawn out till it registered one pound weight when the arm was still, When the arm was in motion with the, spring pulling the plate after it, it might naturally be thought that as it was drawn faster the pull would be greater , but the contrary was observed , toi under these circumstances the spring contracted till it registered less than one ounce When the speed increased to that of a bird the brass plate seemed to float on the air , and not only this, but taking into consideration both the strain and the velocity, it was found that absolutely less power was spent to make the plate move fast than slow, a result which seemed very extraordinary, since in all methods of land and water transport a high speed costs much more power than a slow one for the same distance " These experiments were continued for three years with the general conclusion that by simply moving nn\ given weight of this form fast enough in a horizontal path it was possible to sustain it with less than one-twentieth of the power that Newton's rule called for Langley's final remark was " The first stage of the investigation had shown how much or rather how little power was needed in theory for the horizontal flight of a given weight " Obviously the next stage to be entered upon would be to show how to procure this power with as little weight as possible, and having it how by its means to acquire this horizontal flight in practice In other words, how to acquire the art of flying He indicated the line. A kite in a calm, when sinking for want of sufficient wind to keep it Hying, may be restored by a strong pull on the cord of control Place the pull on board the kite and you will see the kite fly The stronger the pull and the quicker the motion, the heavier the kite may be made. Such are the conditions of flying It is established as beyond doubt that this is the easiest form of locomotion The flight of an eagle has been measured by two theodolites set on an accurately measured base line at 100 miles an hour , pigeons have been known to fly at a rate of 80 miles an hour from Cologne to Pans. Sea gulls and albatrosses keep up a flight of from 12 to 20 miles an hour for days as they circle round a ship , butterflies and insects scarcely eat anything in the perfect state, yet are they ever on the wing No land animal could journey from Cologne to Pans without stopping, at any pace at all, let alone the tremendous speed of these carrier pigeons, whose flight is marvellous, however much may be allowed m the wav of assistance from gales of wind. As for the other feats of the birds above mentioned, which are their ordinary habits, such achievements are unthinkable in the case of any land animal. \dd the story as authentic as astounding, of the albatross caught one day in the Southern Ocean and liberated with a record label, and recaptured twelve days later at a point 3150 miles distant from the point of liberation. If that bird flew straight he averaged nearly 1 1 miles an hour for every hour of the time But he had to range for his food and to sleep, and probably flew double the

distance. What does it mean except that far less power is exerted in flying than in running ? The air is the more penetrable element in comparison with water, as is proved by the bullet which is stopped by water but flies freely through the air. But what shall be said of the difference between the results of earth and air travel ? That brings us back to the starting-point of this article namely the saying of a distinguished aeionaut, one of those perhaps destined to solve the problem of flight, in our time, that the air is waiting to be harnessed to the behests of man. The birds of the air, by making use of the resistance and the other properties of their element, have done the harnessing for themselves Having thus indicated the difficulties ot the problem and reviewed some of the main principles involved, we pass on to the history of the struggle of man for its solution, by the use of machines which, like the birds that fly, are heavier than air The Duke of Argyll said "We all know that a bird is never buoyant. A bird is immensely he ivier than the air. We all know that the moment a bird is shot it falls to the earth , and it must necessarily do it, because one of the essential mechanical principles of flight is weight, without which there can be no momentum, and no mature force capable of moving through atmospheric currents " t

THE STORY OF ANDREE AND HIS BALLOON. The fruitless expedition of the Andree balloon ended the career of the round balloon begun a century before by Montgolfier. Therefore the right place for the story of the former is between the chapters devoted respectively to the balloomsts and the aviators. Andree, who conceived the idea of reaching the North Pole in a balloon, was a Swedish civil engineer of considerable ability and determination, who had paid great attention to aeronautics and become very proficient in the art During his experience of three years of flying over Sweden, Noiway, and the Baltic, he had brought to some perfection — as far as it went — his idea of steering balloons by means of guide ropes trailing on ground or water, astern. When he determined to apply the new system to the navigation of the Arctic ocean, no difficulty was iound in raising the funds, M Nobel and three others subscribing between them the necessary £7000. The project was simplicity itself A balloon was to be constructed of extra strength with a buoyancy of some two months ; it was to be provisioned for several months, provided with collapsible boat in case of accidents, inflated with gas (hydrogen) at some point near the Arctic circle, wait for a south wind, and sail off. What next, was left vague Before the balloon there would be (after the Pole) Greenland, Alaska, and Siberia. If fate took them to the tremendous ice-cap of the first it would be certain death to all But Andree reasoned that the numerous glaciers of this region, quickly cooling the air about them at sea level as they do, always produce air currents in the lower planes radiating outwards in all directions, and as it was proposed to keep the balloon within 300 feet of sea level, there was no danger of a compulsory lourney to the inhospitable shores of Greenland The choice would be, therefore, between^ Alaska and Siberia. With good luck the balloon might one day find itself sailing through the Golden Gate with the whole population of 'Frisco staring agape , with bad it might be landing in the midst of the swamps of the umnhabitated part of eastern Siberia The balloon was prepared to float m the air for fifty-five days. A good deal might happen in fifty-five days. And a good deal did. It is only part of it that we know. The rest — shall we

know it before Ice pack and Tundra give up their dead ? The balloon was made of Pongee silk, of a capacity of 176,582 cubic feet Most of this material was used in fourfold thickness and all was of more than double the strength — as tested by the Nordenfelt company's engineers — stipulated for by the caretul aeronaut Provided with an envelope for protec tion against the snow , with all seams made strongei , by a special cement, than the material itself ot the balloon ; with valves of improved design , and a great tearing rent for emptying the balloon rapidly in case of accidental dragging , with guide ropes trailing astern and giving contiol within fair limits before the wind, and a car and platform below carrying four months provisions and arms and ammunition, which Andree used to refer to in his optimistic way — no one but an optimist of the most inveterate would have undertaken such a venture — as " an unlimited supply of concentrated meat,"* this balloon was the strongest and the best equipped the world has ever seen There is only one thing more amazing than the truly amazing prudential genius shown in every detail of its design and execution. It is that the possessor ot such an abnormal gift of wariness should have trusted himself to a south wind in a region where a south wind is the rarest thing. It was not for want of warning of the fact, for the whole summer of 1896 was wasted at Danes' Island near Spitzbergen, waiting lor the southerly which never came. It was not till the next season that the aeronauts got away, and then not till July, when most of the season had gone by — so capricious are the winds from the south in that quarter of the world How in that second season the balloon was got once again to the starting place, how with its weight and bulk it was safely navigated by the intrepid sailors of the Swedish navy through the rough waters and the ice floes between the ship and the landing-place, how the shed built for it the previous season was renewed , how the gas generating plant was set up with every improvement known to the chemistry of the time for its purification , how special precautions were taken to prevent damage from the swaying inevitable to

so great a mass while being let out of its cover, and how at last it was launched, all this would take too long to tell. The representative of Lachambre, who built the balloon, was there and has told the story m warm and earnest words. It was the 11th of July 1897 Andree had been all the morning considering the weather with the

* Nansen left the Fram with three months' provision and lived on the ice for sixteen months on the above " concentration."

tween two hills apart a lessening ball moves swiftly towards the northern horizon, and is lost Before it are the Sea, the Ice Field, the Unknown "13th July. —12.30 p.m. —82 2 N. —15 5 E — Good journey eastwards. 10 South All goes well on board This is the third message sent by pigeon — Andree " Out of that Unknown, that is all that ever came back from them It was brought by a carrier pigeon caught and killed by a Norway fisherman The pigeon was one of thirty-two carried for purpose of communication Why did not any of the others bring a message ? They would have had to fly 1600 to 2000 miles Pigeons do not fly so far as a rule but a pigeon m 1905 started from a point in Alaska for San Francisco, and was picked up in an exhausted condition at Havre, in Montana, 3100 miles distant These no doubt perished in the northern wastes All we know of the expedition is that on the third day out the treacherous south wind had left it travelling east in the desperate hope of a change to better conditions How desperate, we may judge fiom the fact that the travellers who had nothing else to rely on knew that they had waited in vain a whole season the year before for a south wind RIP

HENSON'S FLYING mCH»E The thing most noteworthy about this invention is its date It was patented in the year 1842 The fact will considerably astonish those who have followed the preceding description of the laws governing the flight of bodies heavier than an Henson anticipated nearly everything in the way of principle though in detail he was as far behind as one might expect from one who, besides living half

it would be found that in a short time they would act sufficiently upon the air to cause the machine to leave the incline and proceed in any desired direction. These propellers were fan paddle wheels working at the sides of the machine. This machine was never flown, though it was heard of again the next year as the machine of Henson and Strmgfellow (see illustration). But whatever happened to it, its design was too remarkable to be passed over in silence. The design was the forerunner, the core, so to speak, of the inventions of the present day. Our illustration is from the copy supplied by the inventor to the Patent Office.

langley's aerodrome, 1896. This machine, the name of which signifies the runner of the air, as seen in the illustration, bears a resemblance to the flying-machine of Henson, which was patented fifty-four years earlier. It was the outcome of the experiments of Langley which have been detailed above, and it was several years in the hands of the inventor before it could be trusted to the air. Langley began with kites and proceeded gradually to tne complete model. Very many attempts to fly the latter failed on account of the difficulties of launching Fortunately the launching was done overwater, for which reason the machine never sustained any damage in its numerous falls Finally it was launched from a house-boat in a secluded part of the Potomac River 20 miles from Washington, from a height of 20 feet Dr. Graham Bell was present and took an instantaneous photograph of the flight that followed He described it as rising steadily in half circles of about 100 yards m diameter and flying at the rate of 25 miles an hour, under direction

wind blowing fresh from the south Would it last ? He decided in his own mind that it would. He left it to his two companions to say what they thought of it, the case being too serious for any interference with their unfettered discretion They thought it would last There was a scene at parting Friends shaking hands, the travellers leaving last words for loved ones far away, tears were falling, voices trembled In the midst of it the voice of the commander was heard " Stnndberg ' Volkmar ' Let us go " The three aeronauts took their places, on the platform under the straining balloon tugging at its ropes The decisive moment had come " One ' Two ' Cut ' " cries the commander in Swedish The seamen cut the ropes and the balloon rose majestically, sailing out of the shed. The first peril was in the very gateway A gust of wind descended upon them from the mountain and the balloon, being encumbered with ropes, did not rise any further, and presently was seen to be rushing down towards sea level The sailors hurry to the boats for a rescue which they think is imperative Fortunately the balloon slows down, just touches the water, and, rising up once more, sails off " The balloon at an altitude of 164 feet," it is the narrative of the builder, who is watching the behaviour of his craft, " speeds rapidly awa} The guide ropes glide over the water, making a very perceptible wake which is visible from the starting-point like the track made by a ship We exchange last signals with our friends Soon we can no longer distinguish them, but we see that they are setting their sails on the bamboo mast There is a change of direction the balloon ls-travel-hng straight to the north at between 18 and 22 miles an hour. If the wind hold they will be at the pole in two days." There was a line of hills in the distance between the exnlorers and the Pole The balloon travelling steadily on clears the top , stands out grey against the blue sky a moment ; and is gone Then be-

a centurj ago, did not bring his invention into practice Here is his own description, taken from the records oi the Patent Office "If any light and flat or nearly flat stone be thrown edgewise in a slightly inclined position, the same will rise in the air till the force exerted is expended, when the article thrown will descend : and it will be readity conceived that if the article possessed in itself a continuous power or force equal to that used in throwing it, the article would continue to ascend so long as the forward part of the surface was upwards in respect to the hinder part, and that such an article, when the power was stopped, or when the inclination was reversed, would descend by gravity only, or by gravity aided by the force of the power contained in the article, if power be contained, thus imitating the flight of a bud." The machine (see illustration) was designed to represent a bird with wings and tail. The bird's body was a car carrying a steam engine of 40 h.p . the wings were outstretched above the body, each made of a light strong framework of bamboo or other wood hollowed, covered with oiled silk, and the tail was arranged for raiding or lowering the plane of flight The wings were carried on two masts rising out of the car and braced to them, "making the whole one trussed beam of light construction." To supplement the steering of the tail, which was to act vertically only, there was a vertical rudder to do the lateral steering. The function of the wings was confined to that which is performed by the wings of the bird, when it is skimming through the air at speed, and they were to exercise a retarding power in descent after the manner of the parachute The inventor, however, relied entirely on the tail action for bringing the machine down at such a flat incline that impact with the earth would be entirely without shock. For starting the machine he preferred an inclined plane like the side of a hill, and he proposed to allow the machine to run foiward down the incline, the propellers being fir<;t set in motion. He thought

Screech owl Sparrow hawk Black owl Goshawk S. owl Glossy Ibis Raven Kite Fish hawk Scavenger vulture Turkey buzzard . . White pelican Flamingo Griffon vulture . . Condor Eared vulture Weight lbs. 0 33 0 336 0.619 0.641 0.67 0.806 1 34 1.41 2 80 3.83 5.6 6.66 6.34 16 52 16 52 17.76 Wing surface sq ft 0 776 0.69 0 92 0 84 1 50 1 24 2 50 3.02 3.01 3.65 5.33 6 32 3 50 11 38 9 80 11.90 ft of Wing surface per Ib. 2 35 2 05 1 49 1.31 2 24 1 54 1 87 2 14 1 08 0 95 0 95 0 95 0.55 0.68 0 59 0 68

Mouillard's table (in L' Empire de Vaiv) may also be quoted —