Читать книгу Balloons, Airships, and Flying Machines - Gertrude Bacon - Страница 4

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During the time of which we are speaking there was living in London a famous chemist named Henry Cavendish. He was the son of a nobleman, and a very rich man; but he shut himself up entirely from the world, and devoted his whole time and energies to the study of science. So afraid was he of being interrupted in his work that he lived the life of a hermit, commanding his servants to keep out of his sight on pain of dismissal, and ordering his dinner daily by means of a note placed on the hall table. In the year 1760—twenty-two years before the Montgolfier brothers began their experiments—this eccentric man had discovered what was then known as “inflammable air,” but what we now call hydrogen gas.

Cavendish’s experiments proved that hydrogen is the lightest of all known substances, being about fourteen times lighter than atmospheric air; and soon after he had made known his researches, it occurred to a certain Dr. Black of Edinburgh that if a sufficiently thin and light bladder were filled with this “inflammable air” it would rise upwards. Dr. Black even went so far as to order a special bladder to be prepared for the purpose; but by the time it was ready he was busy with other work, and the experiment was never made; otherwise it is extremely probable that the honour of inventing the balloon would have been won for this country, and not for France.

A little later Tiberius Cavallo, an Italian chemist living in England, came yet nearer to the great invention, for he filled a number of soap-bubbles with the newly discovered gas, and saw them float high into the air. He did not, however, think at the time that his experiments would lead to any practical result, and so the matter dropped entirely, until the world was suddenly electrified by the tidings of the wonderful hot-air balloon invented by the brothers Montgolfier at Annonay.

The news of this discovery recalled to the minds of many the almost forgotten experiments of the past, and it was forthwith suggested that balloons might be inflated with hydrogen gas more successfully than with hot air. It was resolved immediately to put this theory to the test. A large subscription to defray expenses was raised in Paris without difficulty, for men’s minds were keen on the new-found art of sailing the sky; and M. Charles, Professor of Experimental Philosophy, and two brothers, the Messrs. Roberts, well-known mechanicians, were appointed to construct a suitable balloon and inflate it by the new method.

But they were immediately confronted with a difficulty. Hydrogen being the lightest and most subtle of gases, they were at a loss to know of what material to make their balloon, to prevent the gas escaping. After several failures they eventually constructed a bag of a special kind of silk, and coated it all over with a varnish made of indiarubber dissolved in turpentine. As they found great difficulty in manufacturing large quantities of hydrogen, they were forced to make their bag a comparatively small one, about thirteen feet in diameter. On the 25th of August 1783 the bag was successfully filled, and the ascent was made in Paris in the presence of an enormous crowd. The little balloon rose upwards with immense rapidity, until it was lost to sight in the clouds. Ascending yet higher, it presently burst, and came to the earth in a village, fifteen miles away, after a voyage of three-quarters of an hour.

Attack on the First Charlier Balloon.

In the field where the balloon fell a party of peasants were at work; at its approach they fled in abject terror. From a safe distance they watched the strange new monster settle to earth and lie prone, and then they cautiously drew nearer to inspect it. The silk still heaved with the escaping gas, and the countrymen were fully convinced that an actual living creature of mysterious nature lay before them. One man seized his gun and fired full at it, and then supposing it to be mortally wounded, they all rushed in with flails and pitchforks to complete its destruction, finally tying it to the tail of a horse, who galloped with it all over the country, tearing it to shreds. It was small wonder that after such an occurrence the French Government issued a proclamation to the people, telling them that these aeronautical experiments were to be repeated, and warning them not to be alarmed if they saw a balloon in the air, since it was a perfectly harmless machine filled with gas, and incapable of injuring any one.

This event took place about three months after the first public ascent of the hot-air balloon. The new craft was immediately called a “Charlier,” after its inventor, and to distinguish it from the “Montgolfier.” There followed various exhibitions of the rival airships, and after the voyage of Pilâtre de Rozier and the Marquis D’Arlandes, Messrs. Charles and Roberts resolved also to hazard an ascent in a balloon inflated with hydrogen.

A new machine was therefore constructed, which differed in many important details from all others which had previously been made. It was twenty-seven feet in diameter, of varnished silk, and over it was spread a net of cordage. Instead of a gallery to carry the passengers, as in the “Montgolfier,” a car shaped like a boat was suspended from the net with ropes and hung a few feet below the balloon. A valve to let out the gas was also provided, and the voyagers carried in their car ballast and a barometer to indicate their height. It will thus be seen that this new balloon was in all practical details the same as the balloon of the present day.

The ascent took place on the 17th of December in Paris. Stephen Montgolfier was present, and launched a small hot-air balloon, which amused the onlookers and indicated the direction of the wind. Then MM. Charles and Roberts stepped into the car, and the balloon being liberated, they were immediately carried up to a height of 6000 feet, where a glorious panorama of Paris and the adjacent country was spread out before their delighted vision. After staying aloft about a couple of hours they descended to earth again, and Roberts got out of the car. Charles decided to continue the voyage awhile by himself, and, lightened of his companion’s weight, the balloon this time rose to 10,500 feet. The sun had by this time set upon the earth, but at this height Charles saw it rise once more and set a second time. The thermometer fell far below freezing-point, and he was benumbed with cold and felt violent pains in his ears. When at his greatest elevation he was obliged to pull the valve to prevent the balloon from bursting, and eventually descended without mischance about seven miles from where Roberts had left him.

It would be well now to describe a little more fully the way in which the “Montgolfier” and “Charlier” balloons were inflated. Each of the rival methods had its advantages and also its disadvantages. In the case of the hot-air balloon a shallow pit was dug, in which a quick-burning fire of chopped wool and straw was lighted, and the bag simply suspended over it. The inflation was thus rapid, and its cost comparatively small; the great drawback being that as the bag was of very light material, it ran considerable risk of being ignited by the fire; and all the while it was filling it was the uncomfortable duty of an unfortunate attendant to stand actually inside, roasted with the heat and choked with the smoke, armed with a paddle with which to beat out the flames whenever the bag caught alight.

Filling a Hot-Air Balloon.

This danger of fire was done away with in the method of filling with hydrogen gas. The balloon, suspended from aloft as before, was connected by hose-pipes with a number of casks containing iron or zinc filings upon which dilute sulphuric acid was poured. The effect of mixing these substances together is to set up a brisk chemical action, in the course of which hydrogen gas is given off. In this case the hydrogen thus liberated came through the pipes and filled the balloon. The great disadvantages of this method of filling—which, it may here be mentioned, is occasionally employed at the present day—are the long time it occupies, the great labour entailed, and the enormous expense.

Filling a Hydrogen Gas Balloon.

It is said that when Roberts and Charles returned from their adventurous voyage they were immediately arrested and thrown into prison by order of the King, who considered it his duty to put a stop to his subjects risking their lives in such dangerous enterprises. Public opinion was too strong for him, however, and the two heroes were quickly released, and Charles was rewarded by a pension of £200 a year for life. This newly discovered art of sailing the heavens had indeed fired popular imagination to an extraordinary degree. Probably no invention has ever aroused greater enthusiasm. Not only all France but all the civilised world went wild with excitement for the time. Most extravagant statements were made and written. A new kingdom, it was declared, had been given to mankind to conquer; voyages might be made to the moon and stars, and now it would even be possible to take Heaven itself by storm!

Ascent after ascent took place with the “Montgolfier” and the “Charlier,” both in France and in other countries; nor was it long before the balloon made its appearance in England. In August of the next summer (1784) a Mr Tytler of Edinburgh made some short voyages in a hot-air balloon of his own manufacture, and in the following month a much more adventurous attempt was successfully carried out in London by a young Italian of the name of Vincent Lunardi.

Lunardi was at this time secretary to the Neapolitan Ambassador. He was keenly interested in the subject of ballooning, and presently became fired with a desire to repeat in England those aerial experiments which were creating such a sensation on the Continent. He was only a poor man, and great difficulties stood in the way of accomplishing his object. He had to excite public interest in his venture, to collect subscriptions to defray the cost of his balloon, which was to be a “Charlier,” and to find a suitable site in London for the inflation and ascent. He met with disappointments and disasters enough to discourage a less enthusiastic man, but at length, after many troubles, on the 15th of September his balloon was ready and in process of filling in the grounds of the Honourable Artillery Company, in the city, where 150,000 people had assembled to witness the new wonder.

Vincent Lunardi.

Still Lunardi’s trials were not at an end. The balloon was advertised to ascend at a certain hour; but the supply of gas was insufficient, so that when the time came it was only partially filled, and a long delay ensued. The vast crowd—more than half inclined to believe the whole thing an imposture—began to grow very impatient and unruly, and it was only the presence of the Prince of Wales, afterwards George the Fourth, which kept them in restraint for another hour while the filling continued.

Even then the balloon was not full; but Lunardi felt he could wait no longer. He left behind him the companion who was to have accompanied him, substituted a smaller and lighter car, jumped inside and severed the ropes. Instantly the balloon rose high over the delighted city, as the crowd, led by the Prince himself, rent the air with their cheers. Wild was the excitement in every quarter. At Westminster King George the Third was in conference with Mr. Pitt and his other chief Ministers of State, but when it was known that Lunardi was in the sky the King exclaimed, “Gentlemen, we may resume our deliberations at pleasure, but we may never see poor Lunardi again!” and with one accord they adjourned to watch his progress through telescopes. Tradesmen rushed out of their shops, business men from their offices, even judge and jury from their courts.

Lunardi’s Balloon.

Lunardi continued his voyage over the town into the country beyond. His balloon apparently attained a considerable height, for he found that the condensed moisture round the neck had frozen, and the gas, which to begin with had only two-thirds filled the balloon, presently expanded so much that he was obliged to untie the mouth to relieve the strain. He had taken up with him as companions a dog and a cat. The cat was very ill at ease in the cold of the upper regions, and he resolved to put her out; so, coming down to the ground, he handed her to a country woman standing in a field. Throwing out ballast, he then rose again and continued his voyage for some distance, eventually descending in a meadow near Ware. Some labourers were at work on the spot, but they at first refused to come near him, and a young woman was the first whom he could induce to help him out of his car. A stone with a long inscription, set up in a meadow in the parish of Standon, near Ware, marks to this day the place where the first of all English balloons touched ground.

The following year witnessed a yet bolder enterprise. Blanchard, a French aeronaut, and Dr. Jeffries, an American, determined on an attempt to cross the Channel. On a winter’s day, early in 1785, they had their balloon inflated with hydrogen at Dover and boldly cast off to sea. The cold air appeared to chill the gas more than they had foreseen, and long before they were across the Channel their balloon began settling down upon the water. They threw out all their ballast, then a number of books they were carrying, then their anchor, extra ropes, and other gear. Still it seemed very doubtful whether they would reach the French coast, and as a last resort they began even to throw away their clothes to lighten the balloon. Fortunately at this moment the balloon shot up into the air again, and eventually brought them down in safety near the forest of Guiennes.

So far, although several hundred ascents had been made, and in spite of the many and great dangers of the new-found art and the inexperience of the early voyagers, no fatal accident had marred the delight of sailing the skies. Disasters, however, were soon to come. It is sad to relate that the earliest to fall a victim was the brave Pilâtre de Rozier himself, the first of all men to go aloft in a balloon. Fired with a desire to emulate Blanchard and Jeffries, he decided that he himself would cross the Channel, this time from France to England; and to avoid, as he imagined, the cooling of the gas, which had so nearly proved disastrous on the previous occasion, he hit on the extraordinary idea of combining the principles of both the “Montgolfier” and “Charlier” balloons, and suspending a fire balloon beneath another filled with hydrogen gas. It seems a remarkable thing to us now that no one in those days saw the awful danger of such a combination. The inevitable happened. When the balloon was high in the air the furnace of the hot-air machine set fire to the highly inflammable hydrogen, a fearful explosion followed, and De Rozier and his companion were dashed to pieces.