Читать книгу Harper's New Monthly Magazine, No. IX.—February, 1851.—Vol. II. - Various - Страница 10

(Continued from page 173.)

In the history of aeronautics, the name of Mr. Charles Green, who first turned his attention to the art in 1821, occupies a prominent place. To him the art is indebted for the introduction of carbureted-hydrogen, or coal gas, as the means of inflating balloons. Great as was the improvement effected by the substitution of hydrogen gas for rarefied air, there are serious disadvantages connected with the use of that gas. In the first place, it is procured at vast expense; and, in the second place, it is difficult to obtain it in sufficient quantity, several days of watchful anxiety having been often expended in the vain endeavor to generate a sufficiency of the gas, which, on account of the subtilty of its particles, and its strong affinity for those of the surrounding atmosphere, continued to escape almost as fast as it was produced. Perplexed at the outset with these difficulties and inconveniencies, which had not only rendered experiments comparatively rare, but even threatened the art with premature extinction, Mr. Green conceived that if coal gas, which is much cheaper and can be generated with much greater facility than hydrogen, could be employed for the purpose of inflation, an important object would be gained. To put the truth of his theory to the test, he prepared a balloon, which he inflated with coal gas, and made a successful ascent from the Green Park, on the day of the coronation of George IV. He has subsequently made some hundreds of ascensions from the metropolis, and various other parts of the empire, with balloons so inflated; and, from the year 1821, coal gas has been very generally used in experiments of this nature. Besides its economy and easy production, it has the advantage of being more easily retained than hydrogen, which, for the reasons already given, is much more readily dissipated.

The ingenuity of Mr. Green has been exerted with the view of discovering other improvements in the art of aerial navigation. One great obstacle to the successful practice in the art is, the difficulty of maintaining the power of the balloon for any length of time undiminished in its progress through the air. It is ascertained by the uniform experience of aeronauts, that, between the earth and two miles above the level of the sea, a variety of currents exist, some blowing in one direction and some in another; and when the aeronaut has risen to the elevation where he meets with a current that will waft him in the desired direction, it is of importance for him to be able to preserve that elevation. But the balloon, in consequence of the increase or diminution of weight to which it is liable from a variety of causes, will not keep at that altitude. The great changes which are constantly taking place in the weight of the atmosphere, the deposition of humidity on the surface of the balloon, and its subsequent evaporation by the rise of temperature, the alternate heating and cooling of the gaseous contents of the balloon, according as it may be exposed to the action of the solar rays or screened from them by the interposition of clouds, not to advert to other agencies, less known though not less powerful, all combine in making the machine at one time to ascend and at another to descend. Thus it may be removed out of a favorable into an adverse current. To overcome this difficulty, and enable the aeronaut to keep the balloon at the same level without expending its power, by discharging gas from the valve to lower it, or by casting out a portion of the ballast to raise it – processes which must in time waste the whole power of the largest balloon, and bring it to the earth – Mr. Green suggested the contrivance of a rope of sufficient length and material trailing on the ground beneath, and if over the sea, the rope is to be tied to a vessel filled with liquid ballast, which floats on the surface. This rope will act as a drag on the balloon, when, from any of the causes we have referred to, it tends to rise, for, in that case, it will draw up a portion of the rope, and, by thus adding to its weight, will be impeded in its upward course; and, on the other hand, when, from opposite causes, it tends to descend, it will, during every foot of its descent, have its weight, and consequently its descending tendency, diminished, by throwing on the earth the labor of supporting an additional portion of the rope. This, however, at best, is a clumsy contrivance, and there are various objections to its practical utility. It could hardly be practicable on land, on account of the damage and danger that would be occasioned by the entanglement of the rope in trees and buildings; and at great elevations above the earth, the weight of the rope would become so considerable as to require for its support a large portion of the ascending power of any balloon.

In the United States, many aerial voyages have been performed. The first of these was made by a Frenchman, M. Blanchard, in Jan., 1793, from Philadelphia, at which General Washington was a spectator. Gillio and Robertson, both Europeans, were the next after Blanchard. No Americans were engaged in the business until Mr. Durant, an ingenious citizen of New York, took it up after Robertson. He made a number of aerial excursions, and was shortly followed by new adventurers in the art, among whom the most celebrated is Mr. Wise, a piano-forte maker in Philadelphia, who in 1835 betook himself to the trade of ascending in balloons, and who up to this date has made upward of a hundred ascents.

Mr. Wise is entitled to the merit of having carefully studied and mastered the scientific principles of aeronautics, and he is among the most enthusiastic of his profession. While admitting that the art has advanced but little since its first discovery, compared with other sciences, he anticipates from it, if perseveringly cultivated by men of genius, the most splendid results, adopting, as the motto on the title-page of his work, the couplet from Shakspeare:

"There are more things in heaven and earth, Horatio,

Than are dreamt of in your philosophy."

Some of his feats have been daring enough, and others still more perilous he is willing to undertake.

Not long after commencing the practice of his new profession, Mr. Wise resolved to test the practicability of descending in safety with the balloon, after it had burst, at the elevation of a mile or two. It would then, he conceived, form a parachute, and, from the resistance it would meet with from the atmosphere in its descent, would gently let him down to the earth. Having prepared a balloon of cambric muslin, which he coated with his newly-invented varnish, he ascended, as had been advertised, from Easton, in Pennsylvania, on the 11th of August, 1838, at a few minutes before two o'clock, afternoon, with the full determination of making the experiment, though he had concealed his intention both from the public and from his personal friends. He carried up with him two parachutes, the one containing a cat, and the other a dog. As the balloon approached a dense body of black thunder-clouds, some vivid flashes of lightning, accompanied by violent peals of thunder, greeted his upward course. This gave the first part of his voyage a terrific but grand and imposing appearance. It seemed to him as if heaven's artillery were celebrating these efforts of the new-born science, and, acting on his imagination, this inspired him with a fresh determination to explode the balloon. At different elevations, he detached first one and then another of the parachutes, with their occupants, which landed in safety. At the altitude of about 13,000 feet, the gas became expanded to its utmost tension, and the balloon was still rising, making it evident that, unless the safety-valve were speedily opened to allow a portion of the gas to escape, an explosion would speedily ensue. At this critical moment he became somewhat excited, and looking over the side of his car, he observed the sparkling coruscations of lightning springing from cloud to cloud, a mile beneath him, as the thunder-storm was passing, in its last remnants, below. He took out his watch, noted on his log-book the time – twenty minutes past two – and as he was about returning it to his pocket, thinking at the time whether it were not best, by opening the valve, to abandon, for the present, his favorite idea, the balloon exploded. His confidence in the success of the experiment never forsook him, and yet he admits that this was a moment of awful suspense. The gas rushed with a tempestuous noise from the rupture in the top, and in less than ten seconds, the balloon was emptied of every particle of hydrogen. The descent at first was rapid, and in a moment or two, on looking up, he discovered that the balloon was canting over, but the weight of the car counteracted its tilting tendency, giving it an oscillating motion, which it retained until it reached the earth, which it struck with a violent concussion, and the car striking the earth obliquely, Mr. Wise was thrown forward from it about ten feet. The landing was made on a farm about ten miles from Easton, and many minutes had not elapsed before he had resolved in his mind to repeat the experiment in Philadelphia on the first opportunity.

Having arrived in Philadelphia in the month of September immediately following, he consulted several scientific gentlemen as to his intention. Doubtful of the safety of the experiment, though neither questioning the philosophy of atmospheric resistance, nor the theory of converting the balloon into a parachute, they earnestly endeavored to dissuade him from his purpose. But confident of the perfect safety with which, on scientific principles, he would descend, he publicly announced that he would ascend on the first of October, and explode the balloon at the height of upward of a mile. On the day advertised, at twenty minutes before five o'clock, afternoon, he left the earth in the presence of assembled thousands, and rose almost perpendicularly, in a perfectly clear sky. When the explosion took place, the lower part of the balloon did not immediately invert, as in the former experiment, for in this case the balloon burst open from top to bottom, and caved sideways. At the first discovery of this, he was somewhat alarmed, fearing that it might come down with a continuous accelerated velocity; but from this anxiety he was soon relieved, for it caught the wind like the mainsail of a ship, and slid down upon the atmosphere in a spiral course with a uniform velocity. The concussion, though from the apparent rapidity of the descent it threatened to be violent, was not harder than that which would follow the jumping from an elevation of ten feet to the ground.

From the experience of his numerous aerial excursions, Mr. Wise is of opinion, that, at a considerable elevation, there is a constant and regular current of wind blowing at all times, from west to east, with a velocity of from twenty to forty, and even sixty miles per hour, according to its height from the earth. On the strength of this conviction, he believes it to be perfectly practicable and safe, not only to cross the Atlantic, but even to circumnavigate the globe, in a balloon; and he has expressed his readiness to undertake either of these voyages. About the beginning of the year 1843, he actually proposed to some gentlemen of the city of Philadelphia, the project of making an aerial trip across the Atlantic, in undertaking which, he assured them, he would have as little hesitation as about embarking in the most approved steam-vessel that plied between the ports of New York and Liverpool. At first, supposing him to be in jest, they expressed their willingness to promote the design, but finding that he was in sober earnest, they began to evince conscientious scruples as to the responsibility they would incur, if by any chance his life should fall a sacrifice to the bold adventure. He next determined to petition the Congress of the United States, at their ensuing session, for the necessary pecuniary means; and flattering himself with the hope of the success of his application, to provide against the accidents which might arise from opposing local currents and storms, or from omissions, imperfections, and unforeseen necessities attendant upon all first trials, he issued a proclamation, addressed to all publishers of newspapers in the world, announcing it as his intention to make a trip across the Atlantic in a balloon in the summer of 1844, and calling upon the seafaring community of all climes not to be alarmed should they happen to be in the vicinity of a balloon, either on the ocean or in the atmosphere, but endeavor to give aid to the adventurers. He proposed to have for the car a sea-worthy boat, which would be of service in case the balloon should fail to accomplish the voyage; and the crew was to consist of three individuals – an aeronaut, a sea-navigator, and a scientific landsman.

By the time the Congress met, Mr. Wise had enlarged his idea of crossing the Atlantic to a purpose of sailing round the world. In a petition he presented to that assembly, dated Lancaster City, Dec. 20, 1843, he certifies, that by taking advantage of the current from west to east, which, governed by a great general law, blows at all times round the globe, it was quite practicable, from the improved state to which aeronautic machinery can now be perfected, to travel eastward in a balloon with a velocity that would circumnavigate the globe in from thirty to forty days, and that the aeronaut, by taking advantage of the local currents, could vary from a straight course thirty or forty degrees from the latitude of departure, so as to be able to leave dispatches in Europe and China, and return by way of Oregon Territory to Washington City. He therefore prays the Congress to appropriate the money necessary for constructing an aerostadt of 100 feet in diameter of substantial domestic cotton drilling, with a sea-boat capable of enduring the ocean for a car, and so constructed that the masts and rigging may be stowed, ready for erection into sea service at any time that emergency might require. And he concludes by engaging, that, should his proposal meet with the approbation of the Congress, he would readily submit a plan in detail, and would cheerfully superintend the construction of the machinery at his own expense, asking nothing more than the command or directorship of the first experimental aerial voyage round the globe.

This petition was received and read by the Congress, and referred to the committee of naval affairs. But though the committee to which it was committed might not doubt that Mr. Wise had nerve sufficient to make the attempt, they probably had some doubts as to its practicability and safety, and therefore they made no report. Most men will think that the committee of Congress acted wisely, and that it is fortunate for Mr. Wise himself, that neither the Congress nor his private friends have, by supplying the necessary funds, put it in his power to risk his life in either of those foolish projects. The many accidents and hairbreadth escapes from severe bodily injury, if not from death, which he has met with, during the course of his profession, when undertaking much smaller excursions, scarcely warrant him to conclude, as he does, that such voyages would be attended with fewer risks than sailing in the most approved steam-vessels. To attempt to realize even his first idea of crossing the Atlantic in a balloon, would, in the present imperfect state of aeronautics, be nothing less than madness; to attempt to realize the second, would be "cyclopicus furor," to borrow a phrase from John Calvin – "a gigantic madness;" and we can only account for his forming or broaching such ideas, on the principle of vanity, or of that insensibility to physical danger which the adventurous gradually and unconsciously contract. We do not affirm that such schemes are absolutely impracticable, or that they will never be safely accomplished; for the astonishing discoveries already made in science render it impossible for us to say to what extent the elements may be rendered obedient to the sway of the human will. To speak of crossing the ocean, against wind and tide, in a vessel, by the simple aid of a kettle filled with boiling water, was, not many years ago, laughed at as the ravings of a crack-brained fool. A shaved head and a strait waistcoat were the promised rewards of the original projector of that most noble enterprise. And yet the foaming billows of the great deep are at this day hourly plied by the rushing steam-ship, bounding and puffing recklessly along, as though it were itself the victim of the madness ascribed to its projector, but landing, nevertheless, its precious freight unharmed upon the distant shores. Now, if such stupendous and astonishing results have been realized, what may not man, under the irresistible dominion of the great master-spirit of the age —progress– what may he not accomplish?" But it remains yet to be demonstrated that a pathway in a balloon through the atmosphere is less perilous than one in a ship on the ocean. The safety of traveling in balloons must be tested by smaller trips, before men will believe that these frail vessels of silk, or cambric muslin, may be safely trusted as a means of locomotion across the mighty Atlantic, or, what would be a still greater achievement, around the globe itself.

Having thus briefly traced the history of aeronautics, we shall now inquire into the practical value of the art.

After the discovery of the hydrogen-gas balloon, the most extravagant projects dazzled and bewildered the minds of men. To journey through the air from one part of the globe to another, or even to circumnavigate the globe itself, in balloons, was child's play, compared with the magnificent results that were anticipated. It was fondly expected that the new discovery would open up a channel of communication between the earth and its sister planets, and that the time was not far distant when men would be embarking from the Earth, in a balloon, for the Moon, or for Mercury, Venus, Mars, the Asteroids, or some of the other planets, just as they embarked in a ship for France, Italy, India, China, Africa, or America. They forgot that the laws of gravitation, which bind man as by chains of adamant to this world, would ever interpose an insurmountable obstacle to the realization of such wild imaginings; that the atmosphere has its limits as well as the ocean, extending, it is calculated, not much beyond forty miles above the earth's surface; that, at a certain height, it is as light, by reason of its rarity, as the lightest gas with which a balloon can be inflated, thereby rendering all farther ascent impossible; and that, even before the aeronaut had reached that height, very serious consequences would ensue from the intense cold, from the diminution of atmospheric pressure, and from the inadequacy of a too rarified atmosphere for supporting respiration. Such overwrought expectations, however, produced by the first excitement of a great discovery, soon subsided, when men began soberly to reflect on the immutable laws, or, which is the same thing, the powerful mandate of the Creator, which confines all things within their appointed sphere.

But though the idea of emigrating by means of balloons to foreign worlds was relinquished, there still existed a desire to render them subservient to important terrestrial purposes, and various suggestions were made as to the uses to which they might be applied. It was proposed to employ their power of ascension as a mechanical force for raising water from mines, for transporting obelisks, and placing them on greater elevations, or for raising, without any scaffolding a cross or a vane to the top of a high spire. It was proposed that they might be employed as a means of making an escape from surrounding icebergs in the ocean, or for effecting a landing to otherwise inaccessible mountains, and observing their cloud-capped peaks – for exploring the craters of volcanoes – for traversing vast swamps and morasses – and for the improvement of the infant science of meteorology. It was besides predicted that they would become a safe, easy, and expeditious mode of traveling, and of conveying the products of every land and clime from one part of the globe to another. It is long since Dr. Dick suggested, in his "Christian Philosopher," that the missionaries of the cross might yet be able to avail themselves of the aid of balloons in going forth to distant regions to proclaim to the heathen the unsearchable riches of Christ, and that then there would be a literal fulfillment of the prediction of the last of the inspired seers, "And I saw another angel fly in the midst of heaven, having the everlasting gospel to preach unto them that dwell on the earth, and to every nation, and kindred, and tongue, and people." But to only two purposes has the ascending power of the balloon been as yet applied – to the reconnoitring of hostile armies, by the French, for a short time – and, in one or two instances, to the making of scientific observations. Only a single attempt, and a very absurd one, has been made to get up a traveling balloon. The gold-hunters of America, impatient of the slow process by which ships transport them to the golden regions of California, and, as if determined to press the air into the service of giving them a speedier conveyance, lately proposed to build a balloon, to carry them out at the rate of 200 miles per hour. A model of the machine was exhibited in New York and Philadelphia, and it created considerable sensation in the minds of the credulous. It was stated, in a respectable journal of New York, in 1849, that the machine was actually in course of construction, and the steam-engine finished, but nothing more has since been heard of it. "Had these projectors," says Mr. Wise, "gone on from their miniature model, to the erection of one capable of carrying one or two persons, in order to prove its practicability on a larger scale, there might have been reason to believe that they harbored an idea of its general usefulness. But when the project embraced at once so magnificent a scheme, as that contemplated in the swooping strides toward the modern Dorado, with a cargo of a hundred gold-hunters, it seemed too much for sober-minded people; and brought upon itself philosophical criticism and scientific condemnation, and, with that, a good share of opposition to the hopes and expectations of aerial navigation in any shape."

Aerostation is at present applied to no practical useful purpose; it is a mere plaything, occupying no higher a position than catchpenny mountebank exhibitions. Ascents are made in balloons from no other motive, or for no other object, than to draw money from the pockets of the multitude, by ministering to their enjoyment; and when made by persons properly acquainted with the principles and practice of the art – for by such alone can they be effected with safety – and with those precautions which experience has shown to be requisite, they might be liable to no great objection, so long as the people are willing to pay for them; but if conducted by unqualified persons, or by the most skillful, with a daring recklessness of personal danger, or in a manner involving suffering to any sentient being, they ought to be discouraged in every legitimate way by every friend of humanity, as at variance alike with the principles of morality and with the benevolent lessons of the Christian faith. No man may lawfully peril his own life, or subject the inferior animals to unnecessary pain, for the gratification of the all-devouring thirst of the public for exciting exhibitions; and in the very act of encouraging and witnessing such exhibitions, we are quenching the merciful and fostering the cruel in our natures. Of this objectionable character is the practice recently introduced into France of carrying up donkeys in balloons. The adventure is indeed no new one. It was performed by Mr. Green some twenty years ago. But the merit, or rather the demerit, of having turned it into one of the most popular shows in France, is due to M. Poitevin, who has lately been exciting the gaping admiration of thousands in Paris, by this fool-hardy, barbarous, and contemptible mode of aerostation. Early in July this year (1850), he ascended on horseback in a balloon from Champ de Mars, in the presence of upwards of 10,000 persons, who had paid for admission, and the President of the Republic was one of the spectators. The horse, a handsome dapple gray, had stout cloth placed round its body, and several straps, passed over the shoulders and loins, were united in rings, which were attached by cords to the network of the balloon. In this manner was the animal cruelly suspended in the air, having no resting-place for its feet, nor was there any thing to protect the rider, had he lost his balance or been thrown off. The feat having been more successful than could reasonably have been expected, Mr. Green proposed to amuse the inhabitants of London by a similar adventure. Some of the more humane of the English capital were shocked at the announcement; and the secretary of the Society for the Prevention of Cruelty to Animals made application on the 30th of July to the magistrates to put a stop to the ascent. A case of interference not having been made out to the satisfaction of the magistrates, Mr. Green next day started on his journey to the clouds mounted on a pony. It was put in the car – a plan more humane than that of M. Poitevin, who suspended his pony in the air. But the whole affair was a miserably poor one, and well fitted to bring all such experiments into contempt. The nag was not larger than an under-sized Newfoundland dog; and what made the thing more ridiculous still, the poor creature – which, by the way, had its eyes bandaged, and was strongly tied by cords to the network of the balloon – was so feeble that, on mounting it, Mr. Green had to sustain his own weight by a pile of sand bags placed on either side. This sham equestrian excursion through the air appears to have generally disappointed onlookers, and pony ascensions have not been attempted a second time in England. In France they have met with greater favor. They have been repeated by M. Poitevin and others in the presence of immense multitudes: and it should not be passed over without remark, as one proof among others of what the animals suffer, and, consequently, of the cruelty of the practice, that, in some of these instances, blood flowed from their ears and nostrils. That the practice is dangerous to the aeronaut as well as cruel to the animal, has been the judgment of all reflecting men from the first; and the late melancholy fate of Lieutenant Gale, an English, naval officer, who ascended from the Hippodrome of Vincennes, near Bordeaux, on Sabbath – a very unsuitable day, surely, for such exhibitions – the 8th of September last, mounted on a horse, which was suspended beneath the car of the balloon by girths passed under its body, reads a lesson to which it would be wise to listen. By the aid of several peasants who were in the fields, he effected his descent without any accident to himself or the horse; but, having unfastened the animal, he again rose into the air, and was afterward found dead in a field about a mile from the place where the balloon made its second descent. That this dreadful close of the aeronautic career of Mr. Gale, which he commenced only in 1848, will serve as a warning to this reckless class of adventurers, we hardly anticipate. That it will put a stop to such fool-hardy and hazardous exhibitions, by bringing them into disrepute with the idle multitude, is what we as little expect. So long as men are found sufficiently daring to run the risk, there will not be wanting crowds abundantly ready to pay down their money, and gaze upon the spectacle with a stupid admiration.

It is a wretched result of the art of ballooning, if it can be turned to no better account than this. Can, then, nothing more important be brought out of it? Can it never be rendered subservient to the ordinary purposes of human life? The opinion almost universally prevalent among men, not excluding scientific men, is that it can not. Some aeronauts, indeed, assure us that the time is fast approaching when aerial transition will inevitably be placed as far before railroad and steam-boat transition as the latter are before the old-fashioned sail and horse-power modes. But the most of men place little faith in these flattering anticipations; they listen to or read them with as dogged a skepticism as they read or hear the celebrated vaticination of Bishop Wilkins, that it would be as common for man hereafter to call for his wings when about to make a journey, as it then was to call for his boots and spurs. They doubt whether, with all the characteristic marks of progress that distinguish the present age, balloons will ever become a safe, cheap, and expeditious means of traveling. Whether the aeronauts are most to be justified in their sanguine expectations, or the rest of mankind in their cautious incredulity, time alone will determine. Our judgment, we confess, strongly inclines to the side of the skeptics.

Much is still desiderated, in order to the practicability of ballooning as a generally useful art. A new gas, at once cheap in its production, and of sufficient buoyancy, must be discovered. The gases at present employed for inflating balloons are either too expensive or too heavy. Hydrogen, which is almost fourteen times lighter than common air, is the lightest gas known, but the expense at which it is procured is an insuperable objection to its practical utility. To produce a quantity sufficient to raise the weight of a pound, four and a half pounds of iron or six of zinc, with equal quantities of sulphuric acid, would be required. Carbureted hydrogen or coal gas is much cheaper, and brings the cost of what may be necessary for experimental purposes – though this is by no means inconsiderable – within the compass of more ordinary means. But, as it is only about one half lighter than atmospheric air, it would require a machine of immense size to support any great weight; and the whole experience of ballooning proves the difficulty of managing a body of great magnitude. Another great desideratum in aerial navigation is a power of guiding the balloon according to a given direction – of propelling it through the atmosphere as steam-boats are propelled on the ocean. It has indeed been said that, as nature is very profuse in the variety of atmospherical currents within two miles above the level of the sea, we are not, in sailing through the air, driven to the necessity of attempting to go right against the wind, but have only to ascend or descend, as the case may be, to a current, which will waft the vessel to its desired destination. But were we even sure of always getting a favoring current, which, from the limited amount of observations made, is not yet established beyond a doubt, there is another desideratum – we are in want of an agent adapted for raising and lowering the balloon without any waste of its power, so as to get within the propitious current. Mr. Green's contrivance of the guide rope, is, as we have seen, not likely to answer in practice; and nothing better has yet been discovered.