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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 forever 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.

In a

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. 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 endeavored 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 as fast as possible 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 quite another. The difference may amount to thirty or forty degrees in an ordinary ascent, and, of course, becomes noticeable the higher the flight. The thin air and scanty vapor 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.

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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 stories, 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 33° at one mile, 26° at two miles, 14° at three miles, 8° at 3 miles, where a bed of air heated to 12° was entered, and then, at an elevation of 4 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 181° at two miles, to 254° 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 it had sunk to 26°. For the next 3,000 feet it remained stationary, during which time the aëronauts 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 three hundred 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 mid-day 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 1o. 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 vapor 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 fervor upon the balloon, have been heating and expanding the gas. Lightened also by the dissipation of the moisture contracted in a 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 his ambitious flight, as Icarus had been on his way to the stars, was stopped on before him, by getting too near the sun. He had no wings to melt, it is true, but he had a balloon to rupture; 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 with

out 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 insure 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 aërostat 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 aërial 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 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 aëronauts 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 aërial 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 conclusion 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 23d June, 1867, the balloon started with a north wind directly towards the southsouth-west, and, after a while, due southwest, when we descended. sult 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."

A similar re

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 "aërial 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

cur

rent, 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 34° higher. In the region above, cold reigned, for finelypowdered 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 prodig ious 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 aërial 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 aërial 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 journeys, 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 travel

ling 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 bailoon 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 aërial 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 aëronaut 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 yellowish white, the next pale blue, the third yellow, followed by a ring of grayish 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-by, one of them lifts his hand; but that is just what one of the aëronauts 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 vapor, 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 aëronauts, 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 aërostat, 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.

Lunardi, having ascended from Liverpool in July, 1785, found himself without ballast, and in a balloon insufficiently inflated. He was carried out to sea, retaining of course the power of sinking, which, however, he did not wish to exercise, as he was almost without the means of rising. To lighten the machine, he tossed off his hat, and even this insignificant article afforded him some relief. Soon afterwards, he removed his coat, and this enabled him to mount a little higher, and bear away towards the land. To escape a thunder-cloud, he subsequently divested himself of his waistcoat, and finally succeeded in grappling the earth in a cornfield near Liverpool, spite of his improvidence in the matter of ballast.

It is under such circumstances, however, that we discover the value of the long rope suspended from the car, and which may be let out to the depth of some hundreds of feet. It is a clever substitute for ballast, with this great advantage, that it is retained, not lost; and that it may also be used as a kind of flexible buffer to break the force of the descent. When the balloon is sinking, every inch of the rope which rests upon the ground relieves it of an equivalent portion of its weight: the process is tantamount to the discharge of so

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