Chapter XVIII: Part 18

Before we start, however, the great question is, Dare we start at all? Well might the first aerial navigator, like the anonymous hero _qui fragilem, truci commisit pelago ratem primus_, shudder at his own audacity as he launched his miserable vessel upon the untraversed deep. When it was first determined to send up some human beings to the clouds in a Montgolfier, it was by no means an unnatural suggestion that the experiment should be tried upon a couple of criminals; but French valour would not permit even French rascality to carry off the honour of the exploit, and Pilâtre de Rozier indignantly protested that vile malefactors ought not to have 'the glory of being the first to rise in the air.' Brave men, however, whose courage could not be impeached even in the fieriest hour of battle, have been known to shrink from a balloon when they would have calmly faced a battery. A gallant field-marshal, says Flammarion, 'who had never hesitated to advance through the discharge of cannon and musketry,' declared more than once that he would not, for a whole empire, ascend even in a captive machine! On the other hand, it is related of an old woman (who had been an inmate of Lambeth workhouse for forty years, and who, on losing her son at the age of seventy-five, exclaimed, 'I felt sure I should never bring up that poor child!') that being asked on her hundredth birthday what treat she would like by way of celebrating the occasion, the ancient female decided upon an excursion in the great balloon then tethered at Chelsea. Her wish was granted, and she enjoyed a ride in the atmosphere at the foot of this huge floating gasometer, which was fettered to the earth by a cable of two thousand feet in length. The fair sex, indeed, have never exhibited much timidity in dealing with balloons. Out of the seven hundred persons carried up in the air at various times by the veteran Green, not less than one hundred and twenty were females. 'If,' hinted he to Fonvielle, 'you wish balloons to become popular in France, begin by taking women in them; men will be sure to follow!' Does not this accord to the letter with George Stephenson's dictum, that feminine influence would draw a man from the other side of the globe when nothing else would move him? Not that we think the advice was specially needed for France, for the first lady who made an ascent was a Frenchwoman, Mme. Thiblé; and the first lady who met her death on an aerial excursion was Mme. Blanchard, who belonged to the same nation.

First of all, then, we ought to see the balloon before it is inflated. There it lies, a vast expanse of varnished silk, or calico, or india-rubber cloth, enveloped in netting, and covering many a square yard of ground with its flabby, crumpled form. Nothing more lifeless and uninteresting can well be conceived than the huge shape which, in a short time, will lift itself by degrees from the soil, like a giant creeping gradually into consciousness, and then standing erect in all the pride of its newly-discovered powers, will expand into one of the most stately and picturesque machines ever invented by man. It is even possible to sympathise with M. Flammarion in his heroics when he imagines an aeronaut addressing it in language of mingled insult and adulation:--

"Inert and formless thing, that I can now trample under my
feet, that I can tear with my hands, here stretched dead
upon the ground--my perfect slave--I am about to give thee
life, that thou mayest become my sovereign! In the height
of my generosity I shall make thee even greater than
myself! O vile and powerless thing! I shall abandon myself
to thy majesty, O creature of my hands, and thou shalt
carry my kingdom unto thine own element, which I have
created for thee; thou shalt fly off to the regions of
storms and tempests, and I shall be forced to follow thee!
I shall become thy plaything; thou shalt do what thou wilt
with me, and forget that I gave thee life!"

For many reasons, carburetted hydrogen, or coal gas, is the agent employed to give levity to the machine. In the earlier days of aerostation, hydrogen presented strong temptations. It is the lightest of the gases, being upwards of fourteen times rarer than atmospheric air, and therefore it was naturally regarded as the element best fitted to do man's bidding, and to drag him nearest to the stars. But hydrogen is an expensive article, and needs an elaborate apparatus for its production, whereas coal gas is burnt in every civilized street, and may be obtained in any quantity by connecting a flexible tube with the nearest tap. In the still darker ages of aeronautic science, it is well known that heated air was the element employed; and, going back into yet more benighted times, we find that Father Lana proposed to give buoyancy to copper globes by filling them, as an Hibernian once remarked, with a vacuum; whilst another worthy Père, Galien of Avignon, gravely suggested that balloons should be inflated with attenuated air, brought down from mountain tops in bags prepared for the purpose, in which case they would, of course, ascend to similar heights!

Let us now enter the car. The huge monster above us is swaying to and fro in the breeze, and struggling for freedom like some giant soul which has done its work on earth and is eager to reach its native skies. The cords which hold us captive are loosed, and, as if by instinct, we grasp the nearest rope, or hold fast to the wicker work, to secure ourselves from the effects of our sudden translation--we might almost say projection--through the air. But the first feeling is one of surprise. We find ourselves perfectly stationary, whilst, strange to say, the earth--the great solid globe on which we recently stood, with all its towers and temples, its gazing crowds and spreading landscapes--is seen shooting downwards in space with frightful velocity! Worse still, glancing upwards, the sky appears to be falling, as if the ceiling of the universe had given way; and yonder big dark cloud, which seemed to be motionless when we took our seat, is now tumbling headlong upon us, and will, infallibly, crush our balloon like a moth. It requires some little consideration to correct this delusion, and satisfy ourselves that here, as in many of the moral and social phenomena of life, the change is in us, and not in the world itself.

As we rise, the view below grows more expansive, but, at the same time, it appears to flatten. The hills are planed down, the valleys are filled up, and the rich undulations and inequalities which contribute so much to the picturesque are in a great measure lost to the aerial eye. We seem to be hovering over a huge, variegated ordnance map, tinted for the most part with green; its rivers looking like silver ribbons, its railways like ruled lines, its woods represented by patches of verdure, and its towns exhibiting grooves or gutters for streets, and kitchen areas for squares.

This effect is the more striking when we look perpendicularly down upon tall, slender objects like steeples, pillars, or elevated statues. The Monument of London becomes a mere gilded speck on the pavement. The hapless column in the Place Vendôme, now overthrown by the hands of Frenchmen themselves, was described by an aeronaut as a kind of 'pin stuck head downwards in a cushion.' A view of the statue of Napoleon, as seen from on high, is given by M. Flammarion, and presents a ludicrous picture, the figure being crushed into a sort of black amorphous lump, which would be utterly unintelligible were it not that the shadow exhibits something of the human form, and not inaptly suggests some strong reflections respecting the fallen fortunes of the imperial dynasty. In fact, the landscape seems to be flattened as if some great roller had passed over it, and ironed out all the prominences in order to reduce it to one vast plain.

This appearance may be qualified by another, which, however, is not visible to every voyager. Without going so far as to imagine that the earth will display any portion of its convexity, we certainly should not expect it to assume a concave aspect to the eye. Yet, for the same reason that the sky above us looks like a great vault, and that the clouds overhead slope down towards the horizon, if sufficiently extended, the landscape beneath us should appear to be similarly hollowed were it surveyed from a corresponding elevation. In some degree, and to some susceptible minds, this curious impression is realized in a balloon. The central parts of the expanse below seem to sink and assume a dish-like form, so that, as M. Flammarion observes, we float between two vast concavities, the blue dome of heaven resting upon the green and shallow but inverted dome of earth.

But can we witness all this without a sensation of giddiness? Is not our enjoyment of the scene marred by a strong disposition to vertigo, such as is natural to human heads when raised to perilous altitudes? This tendency, however, is far less prevalent than might be expected in the car of a balloon. Professor Jacobi, who could not look down from a lofty building without dizziness, made his first, perhaps his only ascent without experiencing the least swimming of the brain. The chief feeling of an aeronaut, according to M. Simonin, is one of elation; his sense of individuality becoming so triumphant that he glances down upon the poor wretched globe he has left grovelling in its sins and sorrows, with a species of pity which is probably very much akin to contempt! But this sentiment, according to M. Flammarion, may be combined with another of a much more equivocal description. 'I also felt,' says this gentleman, 'a vague desire to throw myself out of the balloon. Though feeling convinced that it would be certain death, I was under the influence of a mild temptation to allow myself to fall, and my death became, for the moment, a matter of indifference to me.' The lofty air with which this is written, and the supreme _nonchalance_ displayed, are eminently characteristic of the soil, or rather of the sons of France. 'Let me live or let me die,' he seems to say; 'whether I float in these pure ethereal regions, victorious over all the evils of earth, or whether my body lies shattered on those rocks below, a mass of featureless pulp, is a question of no consequence to Camille Flammarion! He is perfectly content whether he figures as an aerial conqueror or as a poor, palpitating corpse!'

We continue rising. The balloon will, of course, persist in doing so until the weight of the included gas and of the entire apparatus exactly balances an equal bulk of the surrounding air. Starting from the earth with all its buoyant power in hand, it would soon acquire a considerable momentum were it not controlled by the resistance of the atmosphere, which reduces its motion to a steady, uniform ascent. This presumes, however, that nothing transpires to alter its gravity. The addition of a few rain-drops to the machine would infallibly slacken its speed, whilst the fall overboard of one of the passengers would convert it for the time into a runaway balloon. When Mr. Cocking severed his parachute from the great _Nassau_, the latter, huge as it was, bounded aloft with such swiftness that whilst the poor fellow was descending to death, the two aeronauts seemed to be mounting to destruction, either by the bursting of the balloon or the stifling emission of gas.

In another way, also, too rapid a start may lead to dangerous consequences. In 1850, MM. Bixio and Barral took their places in the car of a balloon inflated with pure hydrogen. Their object in using this lightest of all aerial fluids was to climb to an elevation of thirty or forty thousand feet; but not having made due allowance for its buoyancy, the machine, when released, shot through the air like a ball from a gun. The envelope expanded so rapidly that it bulged down upon the aeronauts and shrouded them completely, the car being slung at too slight a distance below. Struggling like men beneath a fallen tent, one of them, in his endeavours to extricate himself, tore a hole in the great bag, from which the gas poured upon them, producing illness and threatening suffocation. Precipitately they began to sink, and it was only by tossing everything overboard that they succeeded in landing safely on the earth. They had traversed a bed of clouds 9,000 feet in thickness, reached a height of 19,000 feet, and then performed the return journey all in the space of little more than three quarters of an hour.

Higher and higher we mount. Shall not we knock our sublime heads against the stars, if we continue to ascend in this indefinite way? How rapidly we move, and what curious effects vertical travelling may involve, a single illustration will suggest. Aeronauts may enjoy a spectacle which, at the first mention, might almost recall the retrograde movement of the solar shadow on the dial of Ahaz--namely, that of two sunsets in one day. An early balloonist, M. Charles, was very much impressed by this vision. When he left the earth for an evening excursion, the great luminary had just disappeared, but, said the Frenchman, proudly, 'he rose again for me alone!' 'I had the pleasure of seeing him set twice on the same day.' For was the spectacle such as the dwellers on the soil may command, by permitting the orb to sink behind some elevation, and then mounting it so as to bring him again into view--thus playing at bo-peep with the lord of day. For, continued M. Charles, still more proudly, 'I was the only illuminated object; all the rest of nature being plunged into shadow!'

But now, looking aloft, we observe a mass of clouds, towards which we are rapidly speeding. There are mountains of snow and great threatening rocks, against which it seems as if our fragile vessel would inevitably be dashed. The novice in aerial navigation almost instinctively holds his breath as he sees the distance narrowing between his frail skiff and these frowning piles, and awaits the awful collision. But they open as if by magic, and the balloon glides into the midst without a shock, or a tremor in its frame. We are then enveloped for a time in a sort of obscurity, but we have nothing to fear, for the machine might travel blindfold without dread of the slightest obstruction in these pathless expanses. Destitute of every object which could serve as a guide, we proceed until we emerge into sunshine once more, and then, looking down, we see the clouds through which we have entered closing like a trap-door after us, and shutting us out from the dear old world, where we lead such a life of charmed misery.

Sometimes, however, it seems impossible to rise above the 'smoke and stir of this dim spot, which men call earth.'

In an ascent from Wolverton, in June, 1863, Mr. Glaisher passed through an extraordinary succession of fogs and showers and rain-clouds; and though he soared to a height of 23,000 feet, the balloon was unable to extricate itself from its earthly entanglements. Following a fine rain came a dry fog, which continued for some distance; this traversed, the aeronauts entered a wetting fog, and subsequently a dry one again. When three miles in height, they imagined that they would certainly break through the clouds, but, to their great surprise, nebulous heaps lay above them, beneath them, and all around them. Up they clambered, but at an elevation of four miles dense masses still hung overhead as if to forbid any further progress, and two clouds with fringed edges specially attracted their attention, from the fact that they were unmistakeably nimbi, although formations of this latter class are mostly creatures of the nether sky. On returning, a heavy rain fell pattering on the balloon at an altitude of three miles, and then, lower down, for a space of 5,000 feet, they passed through a curious snowy discharge, the air being full of icy crystals, though the season was high summer.

It is not often, however, that the atmosphere is in this nebulous condition throughout so large a portion of its depth. For days together terrestrials may be enveloped in fog and rain, and in that case must wait patiently until the clouds please to roll off, and drench some other locality; but if at such seasons we were to jump into a balloon, we might soon pass out of the watery zone and soar into the jocund sunshine. Continuing our ascent, therefore, through the dense tract of moisture we first entered, our machine at last lifts its head joyously above the surface, and shaking off the cloudy spray, bounds into a new sphere, where the great giver of light glows with unadulterated ray. We are, in fact, in a new world. We are completely cut off from our native earth by a huge continent of vapour, which appears to have been suddenly petrified into rock.

'Above our heads,' writes Mr. Glaisher, 'rises a noble
roof, a vast dome of the deepest blue. In the east may
perhaps be seen the tints of a rainbow on the point of
vanishing; in the west, the sun silvering the edges of
broken clouds. Below these light vapours may rise a chain
of mountains, the Alps of the sky, rearing themselves one
above the other, mountain above mountain, till the highest
peaks are coloured by the setting sun. Some of these
compact masses look as if ravaged by avalanches, or rent by
the irresistible movement of glaciers. Some clouds seem
built up of quartz, or even diamonds: some, like immense
cones, boldly rise upwards; others resemble pyramids whose
sides are in rough outline. These scenes are so varied and
beautiful that we feel we could remain for ever to wander
above these boundless plains.'

As we ascend, however, a serious question comes into play. To the first adventurer we may suppose that it would present itself with alarming force. Shall we be able to breathe safely in yonder upper regions, where the air is so thin that the lungs must work 'double shift,' as it were, to procure their necessary supply? At the earth's surface, it is well known that the atmosphere presses upon every square inch with a force of from fourteen to fifteen pounds. A column of air forty miles in height resting upon a man's hat, would, of course, crush it flat upon his head in a moment, were it not for an equal resistance within; and, but for the same cause (the equal diffusion of pressure at the same level), we should all go staggering along under our burden of thirty thousand pounds--such is our share of the atmospheric load--or, if laid prostrate, should find ourselves incapable of rising. But of course the pressure grows smaller as we ascend, for the simple reason that the height of the column above us continually decreases. Seeing, moreover, that we are adapted by our organization to existence at the bottom of this aerial ocean, it is natural to expect that at considerable elevations some sensible disturbance of our functions will ensue. At the height of three miles and three-quarters the barometer, which stands at about thirty inches at the level of the sea, has sunk to fifteen inches, exhibiting a pressure of some seven-and-a-half pounds to the square inch, and showing that as much of the atmosphere in weight is below us as there is above. Reaching an elevation of between five and six miles, the mercury would be found to mark ten inches only, representing a pressure of five pounds to the square inch, and proving that two-thirds of the aerial ocean had been surmounted, leaving a thin third alone to be traversed. The following table, as given by Mr. Glaisher, will, however, best express this decline of density:--

'At the height of 1 mile the barometer reading is 24·7 in.
" 2 miles " " 20·3 "
" 3 " " " 16·7 "
" 4 " " " 13·7 "
" 5 " " " 11·3 "
" 10 " " " 4·2 "
" 15 " " " 1·6 "
" 20 " " " 1·0 " less.'

One indication of increasing rarity in the air is to be found in the lowering of the point at which water boils. On the surface of the earth ebullition takes place, as is well known, at 212° Fahr.; but at the top of a mountain like Mont Blanc, where the pressure is so much lightened, and the liquid therefore encounters so much less resistance to its vaporous propensities, it will pass into steam at a temperature of about 178°. At still greater elevations this point becomes so ridiculously reduced--if the expression may be employed--that we might plunge our hand into the fluid when in full simmer, or drink it in the form of tea when absolutely boiling. Of course, under such circumstances, it would be impossible to extract the full flavour of that generous herb unless the process were carried on under artificial pressure, and therefore the most gentle and legitimate of all stimulants must lose much of its potency if decocted at 20,000 feet above the level of the sea.

Another little circumstance is very significant. In opening a flask of pure water at the earth's surface, we should not expect the cork to fly out with an explosion as if it were a flask of Clicquot's sprightliest champagne; but this is what occurs when we reach an altitude where the external pressure is slight compared with the spring of the imprisoned air. In dealing with a bottle of frisky porter or highly impatient soda-water, it may be well to act cautiously, lest the cork should go like a shot through the envelope of the balloon; and in drinking the contents it will be wise to wait till the effervescence has subsided, lest the same results should arise as those which were experienced by the Siamese king, when, instead of mixing his soda powders in his goblet, he put the acid and the alkali separately into his stomach, and left them to settle their affinities there.

Whilst urging his way aloft, therefore, the novice will probably call to mind some of the accounts he has read of poor animals which have been tormented and philosophically murdered in the receiver of an air-pump. He will remember how miserable butterflies and other insects have been unable to use their wings, and, after a few flutterings, have fallen motionless; or how helpless mice, after gasping for a time in hopeless distress, have expired, unwilling martyrs to science. And can he enter such an attenuated atmosphere as the one above him without undergoing some of their agonies, though in a milder and less fatal form? For, on ascending a lofty mountain, the traveller is soon reminded that his lungs are dealing with a much thinner fluid than they inhaled below. Long before he reaches the summit he finds that his drafts upon the atmosphere are increased in consequence of its tenuity, and that the requisite supply can only be obtained with much pulmonary toil. His head begins to ache, a feeling of nausea is frequently induced, and sometimes he experiences the taste of blood in the mouth, or the scent of the same fluid in the nostrils. With throbbing temples and tottering limbs, he drags himself to the peak, and then probably throws himself upon the rock utterly exhausted, his first sentiment being one of relief that the ascent is well over, and his next one of regret that the descent is not already accomplished.

But in estimating the results in such a case, we must remember the great physical exertion which has been incurred. Every traveller who plants himself upon the summit of the Dôme du Gouté must have lifted as many pounds avoirdupois as he weighs, to say nothing of his baggage and personal accoutrements, to a height of some 15,000 feet in the atmosphere by the sheer force of his own muscles. To carry one's own body about is scarcely regarded as porter's work, but what particularly stout man would ever dream of reaching the Grand Plateau, or even attempt to scale the Great Pyramid, without a troop of attendants to drag him to the top? In a balloon, however, all this expenditure of strength is spared. The aeronaut arrives at an elevation far higher than the tallest peak in Europe without squandering as much force as would be required to grind an ounce of coffee. Here, therefore, the influences of rarefied air may be tested without any of the complications arising from previous fatigue or present muscular exhaustion.

Now, the results, as noted by different voyagers, are by no means accordant. In his first ascent, Mr. Glaisher found his pulse throbbing at the rate of a hundred per minute, when he had reached a height of 18,844 feet. At 19,415 feet, his heart began to palpitate audibly. At 19,435, it was beating more vehemently, his pulse had accelerated its pace, his hands and lips were dyed of a dark bluish hue, and it was with great difficulty that he could read his philosophical instruments. At 21,792 feet (upwards of four miles), he seemed to lose the power of making the requisite observations, and a feeling analogous to sea-sickness stole over him, though there was no heaving or rolling in the balloon. Of course, we may well suppose that different individuals will be differently affected. There are some terrestrials who suffer little from sea-sickness, whilst there are others who can scarcely cross the bar of a river without incurring the agonies of that abominable complaint. But Mr. Glaisher seems to be of opinion that the balloon voyager may speedily master the _maladie de l'air_, and become quite at home at any elevation hitherto attained. It is a matter of simple acclimatization. In his own case, he found that he could breathe without inconvenience at a height of three or four miles, whereas his first sallies into that region, as we have seen, were productive of considerable discomfort; and though he regards an altitude of six or seven miles as the frontier line of natural respiration, with a possible reserve in favour of its extension, he hints that artificial appliances may, perhaps, be devised for freighting the aerostat with the fluid in suitable quantity, and so enlarging the sphere of atmospheric enterprise. We are not certain whether this hint has reference to an apparatus for condensing the air; but it is a pleasant fancy, whether practicable or not, to picture a couple of excursionists feeding their lungs by compressing the thin medium around them into pabulum of the needful density.

There is another enemy, however, to encounter, and it is probably to this more than to the attenuation of the air that the painful effects in question are attributable. We allude to the extreme cold of the upper skies. The atmosphere has its polar regions as well as the earth. There frost builds no solid barriers it is true, but his invisible ramparts are a surer defence against intrusion than bulwarks of granite. Even at a height of three or four miles, explorers are apt to find their extremities benumbed, and their faces turning purple or blue. In a night ascent in 1804, Count Zambeccari, who subsequently met his death in consequence of his balloon taking fire, was so severely handled by the frost that he lost the use of his fingers, and was compelled to have some of them amputated. On one occasion, Mr. Coxwell, having laid hold of the grapnel with his naked hand, cried out in pain that he was scalded, which is precisely the punishment inflicted by metallic objects upon all who grasp them incautiously in arctic latitudes, when the temperature is exceedingly low.

Combining, therefore, these two causes, the rarefaction of the upper air, and the crushing influences of frost, we may readily understand why so many bold adventurers have been smitten with asphyxia when pushing their way into such untrodden solitudes. When Andreoli and Brioschi ascended from Padua, in 1808, to a prodigious height, the latter sank into a state of torpor, and shortly afterwards the former found that he had lost the use of his left arm. In the instance already alluded to, when Zambeccari was so mangled by the cold, he and Dr. Grassetti both became insensible, and their companion alone retained the control of his faculties.

On one memorable occasion, Mr. Glaisher and Mr. Coxwell rose to a region which had certainly never been visited before, and most probably will not be speedily visited again. The precise elevation they reached could only be guessed, but it could scarcely be less than 35,000 feet, and might possibly extend to 37,000 feet, or seven miles. This famous ascent was made in 1862 from Wolverhampton. When the aeronauts had soared to a height of some 29,000 feet, about five-and-a-half miles, Mr. Glaisher suddenly discovered that one arm was powerless, and when he tried to move the other, it proved to have been as suddenly stripped of its strength. He then endeavoured to shake himself, but, strange to say, he seemed to possess no limbs. His head fell on his left shoulder, and on his struggling to place it erect, it reeled over to the right. Then his body sank backwards against the side of the car, whilst one arm hung helplessly downwards in the air. In a moment more, he found that all the muscular power which remained in his neck and back had deserted him at a stroke. He tried to speak to his companion, but the power of speech had departed as well. Sight still continued, though dimly; but this, too, speedily vanished, and darkness, black as midnight, drowned his vision in an instant. Whether hearing survived, he could not tell, for there was no sound to break the silence of those lofty solitudes. Consciousness certainly remained; but the mind had ceased to control the body, and the reins of power seemed to have slipped for ever from his grasp. Was this the way men died? And did one faculty after another desert the soul in its extremity, as servile courtiers steal away from the presence of royalty when its last hour has arrived? Soon afterwards consciousness itself disappeared.

Fortunately, this insensibility was not of long duration. He was roused by Mr. Coxwell, but, at first, could only hear a voice exhorting him to 'try.' Not a word could he speak, not an object could he see, not a limb could he move. In a while, however, sight returned; shortly afterwards he rose from his seat, and then found sufficient tongue to exclaim, 'I have been insensible!' 'You have,' was the reply; 'and I too, very nearly!'

At the time Mr. Glaisher was smitten with paralysis, Mr. Coxwell had climbed up to the ring of the balloon, in order to free the valve-rope, which had become entangled. There, his hands were so frozen that he lost the use of them, and was compelled to drop down into the car. His fingers were not simply blue, but positively black with cold, and it became necessary to pour brandy over them to restore the circulation. Observing on his return that Mr. Glaisher's countenance was devoid of animation, he spoke to him, but, receiving no reply, at once drew the conclusion that his companion was in a state of utter unconsciousness. He endeavoured to approach, but found that he himself was lapsing into the same condition. With wonderful presence of mind, however, he attempted to open the valve of the balloon, in order that they might escape from this deadly region, but his hands were too much benumbed to pull the rope. In this fearful extremity, he seized the rope with his teeth, dipped his head downwards two or three times, and found to his relief that the machine was rapidly descending into a more genial sphere. Fortunately, the voyagers reached the ground in safety, without feeling any lasting mischief from their audacious excursion; but it would be difficult to invent a scene better calculated to make the nervous shudder than that of a balloon floating at a height of nearly seven miles, with its occupants awaking from a state of insensibility to discover that their limbs were utterly powerless, that the rope which might enable them to descend was dangling beyond their reach, and that there they must remain until the cold, which had turned every drop of water into ice, should eat away the feeble relics of vitality from their frames.

We proceed. We are now cruising in the full glare of the sun. The rays of that luminary beat upon us with scorching force; but whilst the head seems to be in the Sahara, the feet may be in Spitzbergen. For here, as on the top of a snow-clad mountain, the temperature of the air is one thing, the direct heat of the sun is quite another. The difference may amount to thirty or forty degrees in an ordinary ascent, and of course, becomes more noticeable the higher the flight. The thin air and scanty vapour of the upper regions furnish us with flimsy clothing; whilst in the nether world we wrap the dense medium round us like a mantle, and keep our caloric within our frames.

Is there any law, however, by which the decrease of temperature can be expressed? Seeing that the atmosphere is divided, as it were, into various storeys, these being formed of changing currents, or fugitive strata of clouds, each with its peculiar charge of heat, is it possible that any fixed principle of decline can be detected?

Take a few results. On leaving the ground, where the temperature was 50° (in the afternoon of the 31st of March, 1863), the thermometer indicated 33½° at one mile, 26° at two miles, 14° at three miles, 8° at 3¾ miles, where a bed of air heated to 12° was entered, and then at an elevation of 4½ miles, the instrument had fallen to zero. In descending, the temperature rose to 11° at about three miles in height, it sank to 7° in passing a cold layer, afterwards increased to 18½° at two miles, to 25½° at one mile, and finally settled at 42° on the ground.

Again, on starting (17th July, 1862), the temperature at the surface was 59°, at 4,000 feet, it was 45°, and at 10,000 feet it had sunk to 26°. For the next 3,000 feet it remained stationary, during which time the aeronauts donned additional clothing, in anticipation of a severe interview with the Frost King; but to their great surprise, the thermometer rose to 31° at 15,500 feet, and to 42° at 19,500 feet, by which time they found it necessary to divest themselves of their winter habiliments. Sometimes, indeed, the changes of temperature experienced are startling and unaccountable. At an elevation of 20,000 feet, Barral and Bixio, whilst enveloped in a cloud, found their thermometer at 15° Fahr. Above this cloud, at a height of 23,127 feet, the instrument had sunk to 38° below zero, making a difference of not less than 54° of heat between the two points. Judging from this observation, might we not expect to find all the moisture at those cheerless altitudes curdled into ice? and if our globe is sheathed in an envelope of frozen particles, is the fact wholly without meaning in reference to the aurora and other meteorological phenomena?

From such capricious data, it would seem impossible to extract any definite law; but it has been assumed by many that, taking all things into account, the temperature decreases one degree for every 300 feet of elevation. Putting the matter more exactly, there is, according to Flammarion, a mean abatement of one degree for every 345 feet where the sky is clear, and of one degree for every 354 feet when the heavens are overcast; the decline being quicker when the day is hot than when it is cold, and in the evening than in the morning. Mr. Glaisher, however, feels himself compelled to repudiate this theory of a steady, constant diminution of heat. The results of all his midday experiments amounted to this:--

'The change from the ground to 1,000 feet high was 4° 5´
with a cloudy sky, and 6° 2´ with a clear sky. At 10,000
feet high it was 2° 2´ with a cloudy sky, and 2° with a
clear sky. At 20,000 feet high the decline of temperature
was 1° 1´ with a cloudy sky, and 1° 2´ with a clear sky. At
30,000 feet the whole decline of temperature was found to
be 62°. Within the first 1,000 feet the average space
passed through for 1° was 223 feet with a cloudy sky, and
162 feet with a clear sky. At 10,000 feet the space passed
through for a like decline was 455 feet for the former, and
417 feet for the latter; and above 20,000 feet high the
space with both states of the sky was 1,000 feet nearly for
a decline of 1°. As regards the law just indicated, it is
far more natural and far more consistent than that of a
uniform rate of decrease.'

It should be carefully observed that these conclusions refer to ascents by day; and that by night the temperature augments within certain limits, as Marcet showed, and as numerous experiments have confirmed.

Scarcely less interesting is the question as to the moisture in the atmosphere. Does it decline according to any graduated law? From a large number of observations it has been concluded that the watery vapour increases up to a certain elevation (varying with the season of the year, the hour of the day, and the condition of the sky), and then, having reached this maximum, we find that the air grows continually drier the further we climb. Upon this simple fact much of the physical happiness of our globe depends, for it is the moisture in the lower regions which arrests the efflux of caloric, preserves it for home consumption, and assists the earth in the kindly production of its fruits.

Meanwhile, the rays of the sun playing with unchecked fervour upon the balloon, have been heating and expanding the gas. Lightened also by the dissipation of the moisture contracted in the cloudier portion of the ascent, it probably occurs to the voyager, particularly if he is prone to take alarming views of events, that as the machine rises into a rarer atmosphere the envelope may distend until it actually bursts. Nor is this apprehension, however painful to the nerves, wholly without foundation. Looking up at the flimsy globe above his head, he will observe that it is now fully inflated, though purposely left somewhat flaccid when the journey commenced; and, possibly, he may observe signs of the sun's action on its sides, as if it were blistering under the solar beams. Brioschi, the Neapolitan astronomer, wishing to soar higher than Gay-Lussac, who had reached 23,000 feet on his way to the stars, was stopped on his ambitious flight, as Icarus had been before him, by getting too near the sun. He had no wings to melt, it is true, but he had a balloon to rupture, and the swollen tissue accordingly gave way, though, happily, without involving him in the fate of the presumptuous youth. Will it be credited, however, that any aeronaut could deliberately make an ascent with the express intention of bursting his balloon himself? Yet this has been done without pre-engaging a coroner, and without the slightest wish to commit scientific suicide. The individual by whom this perilous experiment was performed was Mr. Wise, the American. He argued that if the explosion were neatly managed, the collapsing envelope would act as a sort of parachute, the lower part retreating into the upper, and forming a concavity which would present sufficient resistance to ensure a safe and steady descent. Nor were his expectations wholly disappointed. Having risen through a thunderstorm to a height of 13,000 feet, he fired his magazine of hydrogen gas. The car rushed down with awful rapidity, supported, however, by the relics, like a torn umbrella, and alighted upon the ground without inflicting any great violence upon the daring navigator. Not many weeks afterwards, he repeated the exploit, if such it may be called, and in exploding the gas tore the silk receptacle from top to bottom; but, with equal good fortune, he arrived at the earth without a broken limb, the machine having taken a spiral course in falling, which enabled him to descend with uniform velocity.

Having now reached the highest point to which our aerostat will mount so long as its weight continues unchanged, we surrender ourselves to the guidance of the current in which we are involved. In rising to a moderate elevation, a balloon will sometimes shoot through more than one of these aerial streams. Mr. Foster detected the existence of four distinct currents in one experiment, namely, from the E.N.E., N., S.W., and S.S.E., and on the following day found there were three, namely, from the E.N.E., S.E., and S.S.W. Sometimes an upper and an under current may move in opposite directions. Had it not been for this fact, M. Tissandier's _début_ in the clouds might have terminated in his death in the ocean. Ascending with M. Duruof from Calais under somewhat rash and defiant circumstances, their balloon was borne out to sea, not towards the English coast, which might, perhaps, have been reached, but right up the North Sea, where they would probably have perished. Fortunately, after proceeding for some distance, they observed a fleet of _cumuli_ steering for Calais at a depth of some 3,000 feet below, and by dropping into this counter stream they were floated back to land.

There is no subject of greater moment to aeronauts than the determination of the atmospheric currents. Upon this question in a great measure depends the utility of ballooning as an art. We should certainly consider that ocean navigation was in a despicable condition if the utmost we could do for a vessel was to commit it, preciously freighted with our own persons, to the wind and waves, without a sail to propel it or a rudder to guide it in any particular direction. Yet this is pretty much the state of aerial seamanship, except for purposes of vertical travelling. If it could be ascertained that streams flowed to different quarters at different elevations--river rolling over river--then it might be easy to book our balloon for some special point of the compass. But the atmosphere is comparatively unexplored in this respect, and it will require long study before any definite conclusions can be formed, even if such should be ever realized.

That there is some degree of certainty in air-currents may be indicated by a curious fact mentioned by Flammarion, namely, that the traces of his various voyages are all represented by lines which had a tendency to curve in one and the same general direction. 'Thus,' says he, 'on the 23rd June, 1867, the balloon started with a north wind directly towards the south-south-west, and, after a while, due south-west, when we descended. A similar result was observed in every excursion, and the fact led me to believe that above the soil of France the currents of the atmosphere are constantly deviated circularly, and in a south-west-north-east-south direction.'

Still more curious is a fact which Mr. Glaisher may be said to have discovered.

We are accustomed to talk much of the Gulf Stream. It is as popular a marine phenomenon as the Great Sea Serpent. For some time it has figured in meteorology as the subtle agent to which all climatic eccentricities, and not a few climatic advantages, are ascribed; but what shall we say to a genuine 'aeria Gulf Stream?' What, to a stream flowing through the atmosphere in kindly correspondence with the beneficent current which sweeps through the Atlantic below?

On the 12th January, 1864, Mr. Glaisher left the earth, where a south-east wind was prevailing. At a height of 1,300 feet he was surprised to enter a warm current, 3,000 feet in thickness, which was flowing from the south-west, that is, in the direction of the Gulf Stream itself. At the elevation in question the temperature, according to the usual calculation, should have been 4° or 5° lower than that at the ground, whereas it was 3½° higher. In the region above, cold reigned, for finely-powdered snow was falling into this atmospheric river. Here, therefore, was a stream of heated air previously unsuspected, which, if its course is steady, as it appears to be during winter, constitutes a prodigious accession to our resources, and adds another to the many meteorological blessings the world enjoys.

'The meeting with this south-west current (writes Mr.
Glaisher) is of the highest importance, for it goes far to
explain why England possesses a winter temperature so much
higher than our northern latitudes. Our high winter
temperature has hitherto been mostly referred to the
influence of the Gulf Stream. Without doubting the
influence of this natural agent, it is necessary to add the
effect of a parallel atmospheric current to the oceanic
current coming from the same regions--a true aerial Gulf
Stream. This great energetic current meets with no
obstruction in coming to us, or to Norway, but passes over
the level Atlantic without interruption from mountains. It
cannot, however, reach France without crossing Spain and
the lofty range of the Pyrenees, and the effect of these
cold mountains in reducing its temperature is so great that
the former country derives but little warmth from it.'

The velocity of these atmospheric streams must, of course, differ considerably; but, however rapid may be their motion, the balloonist will not fail to notice the feeling of personal immobility which gives such a peculiar character to aerial travelling. We can hardly realize the idea of being transported, say, from London to Dover, without experiencing sundry jars of the muscles or tremors of the nerves, even if we escape, as is by no means certain, the chances of a collision; but M. Flammarion remarks in reference to one of his journies, that the distance accomplished was a hundred and twenty miles, 'during the whole of which time we never felt ourselves in motion at all.' No better illustration of this exemption from the jerks and joltings of terrestrial locomotion could be given than a simple experiment. A tumbler was filled with water till the liquid stood bulging over the brim. The balloon was travelling with the velocity of a railway train, and sometimes rising, sometimes falling, through hundreds of feet at a time, yet not a single drop of the fluid was swung out of the glass!

Striking as the fact is, it would be still more surprising if it were otherwise; for, having once entered a current of air, and surrendered our machine to its guidance, we become, as it were, part of the medium in which we are immersed. The balloon has no longer any will of its own, or of its occupants, except for purposes of ascent or descent. It glides along with the stream, and, coming athwart no obstructions, it knows none of the bumpings to which more grovelling vehicles are exposed. Hence results another consequence which will scarcely escape attention, namely, that here, in the very place of winds, we experience no wind whatever. You may sit in the car of a balloon without undergoing much danger from draughts. There are no fierce gales to encounter, and therefore there are no weather-beaten mariners aloft. If we come to a spot where two breezes meet in battle, or, if two currents of differing directions were so sharply defined that the upper part of the machine could emerge into the superior stream whilst the lower part was in the keeping of the inferior, then very unpleasant results might ensue; but these are not events which aerial navigators have frequently to record in the serener regions aloft.

And as all motion seems to have ceased, except what is due to the rotatory action of the balloon, so all sound appears to have expired. On earth we have nothing to compare with the awful stillness of these airy solitudes. Some noise--be it the sighing of the wind, the pattering of the rain, the fall of a crumbling particle of rock--will break the tranquillity of the vale, the loneliest wilderness, the loftiest peak. But here nature appears to be voiceless, and silence, 'the prelude of that which reigns in the interplanetary space,' seems to be a consecrated thing, as if it were destined to remain uninterrupted until the Trumpet of Judgment shall wake the world.

But did we say we were in absolute solitude? If so, imagine the startled look of an aeronaut when, on issuing from a cloud, he sees before him, at the distance of some thirty or forty yards, the figure of another balloon! If a feeling of horror creeps over him at the sight, he might well be pardoned, for his first thought would doubtless be that it was some phantom of the air sent to lure him to destruction, as the Flying Dutchman is reported to do with mariners at sea. One remarkable feature, however, instantly attracts his attention. The car of the stranger is placed in the centre of a huge disc, consisting of several concentric circles--the interior one being of yellowish white, the next pale blue, the third yellow, followed by a ring of greyish red, and, finally, by one of light violet. That car, too, is occupied. Its tenants are engaged in returning the scrutiny, and their attitudes express equal surprise. By-and-bye, one of them lifts his hand; but that is just what one of the aeronauts has done. Another motion is made, and this is imitated to the letter. A laugh from the living voyagers follows. They have discovered that the stranger is an optical apparition, for on examination it is found to correspond with their own machine, line for line, rope for rope, and man for man, except that they, the living ones, are not surrounded by a glory as if they were resplendent saints.

This beautiful phenomenon is due to the reflection or diffraction of light from the little vesicles of vapour, and must not be confounded with the ordinary shadow of the balloon which, under fitting conditions, and in a more or less elongated form, generally appears to accompany us like some spectral shark in pitiless pursuit of an infected ship.

It is now time, however, to commence our homeward voyage. In other words, we must tumble perpendicularly to the earth, but so regulate our fall that no bones shall be broken, and no concussion, if possible, sustained. To do this from an elevation of three or four miles must strike us as a vastly more dangerous problem than the ascent to a similar height. The valve at the top of the balloon affords us the means of diminishing its relative levity by a gradual discharge of the gas. But this process must be cautiously performed, otherwise the machine may start off like a steed which is suddenly inspired with a new life when its face is turned towards its home. Hence the necessity of retaining a proper amount of ballast to control its impatient descent. If it should sink too rapidly, the emptying of a bag or two will check its pace, and even give it an upward turn for the time, so that the aeronauts, in rising again, will sometimes hear a pattering upon the balloon, which proves to be the very shower of sand they have just ejected.

So delicately, indeed, does the machine respond to any alteration in its weight, that once, when M. Tissandier threw out the bone of a chicken he had been assisting to consume, his companion gravely reproved him, and, on consulting the barometer, he was compelled to admit that this small act of imprudence had caused them to 'rise from twenty to thirty yards!'

Not unfrequently it happens that a balloon has to dive through such heavy clouds, or through such a rainy region, that its weight is considerably increased by the deposited moisture. In passing through a dense stratum, 8,000 feet in thickness, Mr. Coxwell's aerostat, on one occasion, became so loaded that, though he had reserved a large amount of ballast, which was hurled overboard as fast as possible, the machine sped to the earth with a shock which fractured nearly all the instruments.