by Jules Verne
CHAPTER XV.
HYPERBOLA OR PARABOLA.
We may, perhaps, be astonished to find Barbicane and his companions solittle occupied with the future reserved for them in their metal prisonwhich was bearing them through the infinity of space. Instead of askingwhere they were going, they passed their time making experiments, as ifthey had been quietly installed in their own study.
We might answer that men so strong-minded were above such anxieties--thatthey did not trouble themselves about such trifles--and that they hadsomething else to do than to occupy their minds with the future.
The truth was that they were not masters of their projectile; they couldneither check its course, nor alter its direction.
A sailor can change the head of his ship as he pleases; an aeronaut cangive a vertical motion to his balloon. They, on the contrary, had no powerover their vehicle. Every maneuver was forbidden. Hence the inclinationto let things alone, or as the sailors say, "let her run."
Where did they find themselves at this moment, at eight o'clock in themorning of the day called upon the earth the 6th of December? Verycertainly in the neighbourhood of the moon, and even near enough for herto look to them like an enormous black screen upon the firmament. As tothe distance which separated them, it was impossible to estimate it. Theprojectile, held by some unaccountable force, had been within four milesof grazing the satellite's north pole.
Illustration: A DISCUSSION AROSE.
But since entering the cone of shadow these last two hours, had thedistance increased or diminished? Every point of mark was wanting bywhich to estimate both the direction and the speed of the projectile.
Perhaps it was rapidly leaving the disc, so that it would soon quit thepure shadow. Perhaps, again, on the other hand, it might be nearing itso much that in a short time it might strike some high point on theinvisible hemisphere, which would doubtlessly have ended the journey muchto the detriment of the travellers.
A discussion arose on this subject, and Michel Ardan, always ready withan explanation, gave it as his opinion that the projectile, held by thelunar attraction, would end by falling on the surface of the terrestrialglobe like an aerolite.
"First of all, my friend," answered Barbicane, "every aerolite does notfall to the earth; it is only a small proportion which do so; and if wehad passed into an aerolite, it does not necessarily follow that weshould ever reach the surface of the moon."
"But how if we get near enough?" replied Michel.
"Pure mistake," replied Barbicane. "Have you not seen shooting stars rushthrough the sky by thousands at certain seasons?"
"Yes."
"Well, these stars, or rather corpuscules, only shine when they areheated by gliding over the atmospheric layers. Now, if they enter theatmosphere, they pass at least within forty miles of the earth, but theyseldom fall upon it. The same with our projectile. It may approach verynear to the moon, and yet not fall upon it."
"But then," asked Michel, "I shall be curious to know how our erringvehicle will act in space?"
"I see but two hypotheses," replied Barbicane, after some moments'reflection.
"What are they?"
"The projectile has the choice between two mathematical curves, and itwill follow one or the other according to the speed with which it isanimated, and which at this moment I cannot estimate."
"Yes," said Nicholl, "it will follow either a parabola or a hyperbola."
"Just so," replied Barbicane. "With a certain speed it will assume theparabola, and with a greater the hyperbola."
"I like those grand words," exclaimed Michel Ardan; "one knows directlywhat they mean. And pray what is your parabola, if you please?"
"My friend," answered the captain, "the parabola is a curve of thesecond order, the result of the section of a cone intersected by a planeparallel to one of its sides."
"Ah! ah!" said Michel, in a satisfied tone.
"It is very nearly," continued Nicholl, "the course described by a bomblaunched from a mortar."
"Perfect! And the hyperbola?"
"The hyperbola, Michel, is a curve of the second order, produced by theintersection of a conic surface and a plane parallel to its axis, andconstitutes two branches separated one from the other, both tendingindefinitely in the two directions."
"Is it possible!" exclaimed Michel Ardan in a serious tone, as if theyhad told him of some serious event. "What I particularly like in yourdefinition of the hyperbola (I was going to say hyperblague) is that itis still more obscure than the word you pretend to define."
Nicholl and Barbicane cared little for Michel Ardan's fun. They were deepin a scientific discussion. What curve would the projectile follow? wastheir hobby. One maintained the hyperbola, the other the parabola. Theygave each other reasons bristling with _x_. Their arguments were couchedin language which made Michel jump. The discussion was hot, and neitherwould give up his chosen curve to his adversary.
This scientific dispute lasted so long that it made Michel very impatient.
"Now, gentlemen cosines, will you cease to throw parabolas and hyperbolasat each other's heads? I want to understand the only interesting questionin the whole affair. We shall follow one or other of these curves? Good.But where will they lead us to?"
"Nowhere," replied Nicholl.
"How, nowhere?"
"Evidently," said Barbicane, "they are open curves, which may be prolongedindefinitely."
"Ah, savants!" cried Michel; "and what are either the one or the otherto us from the moment we know that they equally lead us into infinitespace?"
Barbicane and Nicholl could not forbear smiling. They had just beencreating "art for art's sake." Never had so idle a question been raisedat such an inopportune moment. The sinister truth remained that, whetherhyperbolically or parabolically borne away, the projectile would neveragain meet either the earth or the moon.
What would become of these bold travellers in the immediate future? Ifthey did not die of hunger, if they did not die of thirst, in some days,when the gas failed, they would die from want of air, unless the coldhad killed them first. Still, important as it was to economize the gas,the excessive lowness of the surrounding temperature obliged them toconsume a certain quantity. Strictly speaking, they could do without its_light_, but not without its _heat_. Fortunately the caloric generated byReiset's and Regnaut's apparatus raised the temperature of the interiorof the projectile a little, and without much expenditure they were ableto keep it bearable.
But observations had now become very difficult. The dampness of theprojectile was condensed on the windows and congealed immediately. Thiscloudiness had to be dispersed continually. In any case they might hopeto be able to discover some phenomena of the highest interest.
But up to this time the disc remained dumb and dark. It did not answerthe multiplicity of questions put by these ardent minds; a matter whichdrew this reflection from Michel, apparently a just one,--
"If ever we begin this journey over again, we shall do well to choosethe time when the moon is at the full."
"Certainly," said Nicholl, "that circumstance will be more favourable.I allow that the moon, immersed in the sun's rays, will not be visibleduring the transit, but instead we should see the earth, which wouldbe full. And what is more, if we were drawn round the moon, as at thismoment, we should at least have the advantage of seeing the invisiblepart of her disc magnificently lit."
"Well said, Nicholl," replied Michel Ardan. "What do you think, Barbicane?"
"I think this," answered the grave president: "If ever we begin thisjourney again, we shall start at the same time and under the sameconditions. Suppose we had attained our end, would it not have beenbetter to have found continents in broad daylight than a country plungedin utter darkness? Would not our first installation have been made underbetter circumstances? Yes, evidently. As to the _invisible_ side, wecould have visited it in our exploring expeditions on the lunar globe.So that the time of the full moon was well chosen. But we ought to havearrived at the end; and i
n order to have so arrived, we ought to havesuffered no deviation on the road."
"I have nothing to say to that," answered Michel Ardan. "Here is, however,a good opportunity lost of observing the other side of the moon."
But the projectile was now describing in the shadow that incalculablecourse which no sight-mark would allow them to ascertain. Had itsdirection been altered, either by the influence of the lunar attraction,or by the action of some unknown star? Barbicane could not say. Buta change had taken place in the relative position of the vehicle; andBarbicane verified it about four in the morning.
The change consisted in this, that the base of the projectile hadturned towards the moon's surface, and was so held by a perpendicularpassing through its axis. The attraction, that is to say the _weight_,had brought about this alteration. The heaviest part of the projectileinclined towards the invisible disc as if it would fall upon it.
Was it falling? Were the travellers attaining that much desired end? No.And the observation of a sign-point, quite inexplicable in itself, showedBarbicane that his projectile was not nearing the moon, and that it hadshifted by following an almost concentric curve.
This point of mark was a luminous brightness, which Nicholl sightedsuddenly, on the limit of the horizon formed by the black disc. Thispoint could not be confounded with a star. It was a reddish incandescencewhich increased by degrees, a decided proof that the projectile wasshifting towards it and not falling normally on the surface of the moon.
"A volcano! it is a volcano in action!" cried Nicholl; "a disembowellingof the interior fires of the moon! That world is not quite extinguished."
"Yes, an eruption," replied Barbicane, who was carefully studying thephenomenon through his night glass. "What should it be, if not a volcano?"
"But, then," said Michel Ardan, "in order to maintain that combustion,there must be air. So an atmosphere _does_ surround that part of themoon."
"_Perhaps_ so," replied Barbicane, "but not necessarily. The volcano,by the decomposition of certain substances, can provide its own oxygen,and thus throw flames into space. It seems to me that the deflagration,by the intense brilliancy of the substances in combustion, is producedin pure oxygen. We must not be in a hurry to proclaim the existence ofa lunar atmosphere."
The fiery mountain must have been situated about the 45 deg. southlatitude on the invisible part of the disc; but, to Barbicane's greatdispleasure, the curve which the projectile was describing was takingit far from the point indicated by the eruption. Thus he could notdetermine its nature exactly. Half an hour after being sighted, thisluminous point had disappeared behind the dark horizon; but theverification of this phenomenon was of considerable consequence in theirselenographic studies. It proved that all heat had not yet disappearedfrom the bowels of this globe; and where heat exists, who can affirmthat the vegetable kingdom, nay, even the animal kingdom itself, has notup to this time resisted all destructive influences? The existence ofthis volcano in eruption, unmistakably seen by these earthly savants,would doubtless give rise to many theories favourable to the gravequestion of the habitability of the moon.
Barbicane allowed himself to be carried away by these reflections. Heforgot himself in a deep reverie in which the mysterious destiny of thelunar world was uppermost. He was seeking to combine together the factsobserved up to that time, when a new incident recalled him briskly toreality. This incident was more than a cosmical phenomenon; it was athreatened danger, the consequences of which might be disastrous in theextreme.
Suddenly, in the midst of the ether, in the profound darkness, anenormous mass appeared. It was like a moon, but an incandescent moonwhose brilliancy was all the more intolerable as it cut sharply on thefrightful darkness of space. This mass, of a circular form, threw alight which filled the projectile. The forms of Barbicane, Nicholl, andMichel Ardan, bathed in its white sheets, assumed that livid spectralappearance which physicians produce with the fictitious light of alcoholimpregnated with salt.
Illustration: A PREY TO FRIGHTFUL TERROR.
"By Jove!" cried Michel Ardan, "we are hideous. What is thatill-conditioned moon?"
"A meteor," replied Barbicane.
"A meteor burning in space?"
"Yes."
This shooting globe suddenly appearing in shadow at a distance of at most200 miles, ought, according to Barbicane, to have a diameter of 2000yards. It advanced at a speed of about one mile and a half per second.It cut the projectile's path and must reach it in some minutes. As itapproached it grew to enormous proportions.
Imagine, if possible, the situation of the travellers! It is impossibleto describe it. In spite of their courage, their _sang-froid_, theircarelessness of danger, they were mute, motionless with stiffened limbs,a prey to frightful terror. Their projectile, the course of which theycould not alter, was rushing straight on this ignited mass, more intensethan the open mouth of an oven. It seemed as though they were beingprecipitated towards an abyss of fire.
Barbicane had seized the hands of his two companions, and all threelooked through their half-open eyelids upon that asteroid heated to awhite heat. If thought was not destroyed within them, if their brainsstill worked amidst all this awe, they must have given themselves up forlost.
Two minutes after the sudden appearance of the meteor (to them twocenturies of anguish) the projectile seemed almost about to strike it,when the globe of fire burst like a bomb, but without making any noisein that void where sound, which is but the agitation of the layers ofair, could not be generated.
Nicholl uttered a cry, and he and his companions rushed to the scuttle.What a sight! What pen can describe it? What palette is rich enough incolours to reproduce so magnificent a spectacle?
It was like the opening of a crater, like the scattering of an immenseconflagration. Thousands of luminous fragments lit up and irradiatedspace with their fires. Every size, every colour, was there intermingled.There were rays of yellow and pale yellow, red, green, grey--a crownof fireworks of all colours. Of the enormous and much-dreaded globethere remained nothing but these fragments carried in all directions,now become asteroids in their turn, some flaming like a sword, somesurrounded by a whitish cloud, and others leaving behind them trains ofbrilliant cosmical dust.
These incandescent blocks crossed and struck each other, scatteringstill smaller fragments, some of which struck the projectile. Its leftscuttle was even cracked by a violent shock. It seemed to be floatingamidst a hail of howitzer shells, the smallest of which might destroy itinstantly.
The light which saturated the ether was so wonderfully intense, thatMichel, drawing Barbicane and Nicholl to his window, exclaimed, "Theinvisible moon, visible at last!"
And through a luminous emanation, which lasted some seconds, the wholethree caught a glimpse of that mysterious disc which the eye of man nowsaw for the first time. What could they distinguish at a distance whichthey could not estimate? Some lengthened bands along the disc, real cloudsformed in the midst of a very confined atmosphere, from which emergednot only all the mountains, but also projections of less importance; itscircles, its yawning craters, as capriciously placed as on the visiblesurface. Then immense spaces, no longer arid plains, but real seas,oceans, widely distributed, reflecting on their liquid surface all thedazzling magic of the fires of space; and, lastly, on the surface of thecontinents, large dark masses, looking like immense forests under therapid illumination of a brilliance.
Was it an illusion, a mistake, an optical illusion? Could they give ascientific assent to an observation so superficially obtained? Daredthey pronounce upon the question of its habitability after so slight aglimpse of the invisible disc?
Illustration: WHAT A SIGHT.
But the lightnings in space subsided by degrees; its accidentalbrilliancy died away; the asteroids dispersed in different directionsand were extinguished in the distance. The ether returned to itsaccustomed darkness; the stars, eclipsed for a moment, again twinkled inthe firmament, and the disc, so hastily discerned, was again buried inimpenetrable
night.