CHAPTER XV
HYPERBOLA OR PARABOLA
We may, perhaps, be astonished to find Barbicane and hiscompanions so little occupied with the future reserved for themin their metal prison which was bearing them through theinfinity of space. Instead of asking where they were going,they passed their time making experiments, as if they had beenquietly installed in their own study.
We might answer that men so strong-minded were above suchanxieties-- that they did not trouble themselves about suchtrifles-- and that they had something else to do than tooccupy their minds with the future.
The truth was that they were not masters of their projectile;they could neither check its course, nor alter its direction.
A sailor can change the head of his ship as he pleases; anaeronaut can give a vertical motion to his balloon. They, onthe contrary, had no power over their vehicle. Every maneuverwas forbidden. Hence the inclination to let things alone, or asthe sailors say, "let her run."
Where did they find themselves at this moment, at eight o'clock inthe morning of the day called upon the earth the 6th of December?Very certainly in the neighborhood of the moon, and even nearenough for her to look to them like an enormous black screen uponthe firmament. As to the distance which separated them, it wasimpossible to estimate it. The projectile, held by someunaccountable force, had been within four miles of grazing thesatellite's north pole.
But since entering the cone of shadow these last two hours, hadthe distance increased or diminished? Every point of mark waswanting by which to estimate both the direction and the speed ofthe projectile.
Perhaps it was rapidly leaving the disc, so that it would soonquit the pure shadow. Perhaps, again, on the other hand, itmight be nearing it so much that in a short time it might strikesome high point on the invisible hemisphere, which would doubtlesslyhave ended the journey much to the detriment of the travelers.
A discussion arose on this subject, and Michel Ardan, alwaysready with an explanation, gave it as his opinion that theprojectile, held by the lunar attraction, would end by fallingon the surface of the terrestrial globe like an aerolite.
"First of all, my friend," answered Barbicane, "every aerolitedoes not fall to the earth; it is only a small proportion whichdo so; and if we had passed into an aerolite, it does not necessarilyfollow that we should ever reach the surface of the moon."
"But how if we get near enough?" replied Michel.
"Pure mistake," replied Barbicane. "Have you not seen shootingstars rush through the sky by thousands at certain seasons?"
"Yes."
"Well, these stars, or rather corpuscles, only shine when theyare heated by gliding over the atmospheric layers. Now, ifthey enter the atmosphere, they pass at least within fortymiles of the earth, but they seldom fall upon it. The same withour projectile. It may approach very near to the moon, and notyet fall upon it."
"But then," asked Michel, "I shall be curious to know how ourerring vehicle will act in space?"
"I see but two hypotheses," replied Barbicane, after somemoments' reflection.
"What are they?"
"The projectile has the choice between two mathematical curves,and it will follow one or the other according to the speed withwhich it is animated, and which at this moment I cannot estimate."
"Yes," said Nicholl, "it will follow either a parabola ora hyperbola."
"Just so," replied Barbicane. "With a certain speed it willassume the parabola, and with a greater the hyperbola."
"I like those grand words," exclaimed Michel Ardan; "one knowsdirectly what they mean. And pray what is your parabola, ifyou please?"
"My friend," answered the captain, "the parabola is a curve ofthe second order, the result of the section of a coneintersected by a plane parallel to one of the sides."
"Ah! ah!" said Michel, in a satisfied tone.
"It is very nearly," continued Nicholl, "the course described bya bomb launched from a mortar."
"Perfect! And the hyperbola?"
"The hyperbola, Michel, is a curve of the second order, producedby the intersection of a conic surface and a plane parallel toits axis, and constitutes two branches separated one from the other,both tending indefinitely in the two directions."
"Is it possible!" exclaimed Michel Ardan in a serious tone, asif they had told him of some serious event. "What I particularlylike in your definition of the hyperbola (I was going to sayhyperblague) is that it is still more obscure than the word youpretend to define."
Nicholl and Barbicane cared little for Michel Ardan's fun.They were deep in a scientific discussion. What curve wouldthe projectile follow? was their hobby. One maintained thehyperbola, the other the parabola. They gave each other reasonsbristling with _x_. Their arguments were couched in languagewhich 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 Michelvery impatient.
"Now, gentlemen cosines, will you cease to throw parabolas andhyperbolas at each other's heads? I want to understand the onlyinteresting question in the whole affair. We shall follow oneor the other of these curves? Good. But where will they leadus to?"
"Nowhere," replied Nicholl.
"How, nowhere?"
"Evidently," said Barbicane, "they are open curves, which may beprolonged indefinitely."
"Ah, savants!" cried Michel; "and what are either the one or theother to us from the moment we know that they equally lead usinto infinite space?"
Barbicane and Nicholl could not forbear smiling. They had justbeen creating "art for art's sake." Never had so idle a questionbeen raised at such an inopportune moment. The sinister truthremained that, whether hyperbolically or parabolically borne away,the projectile would never again meet either the earth or the moon.
What would become of these bold travelers in the immediate future?If they 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 cold had killed them first. Still, important as it wasto economize the gas, the excessive lowness of the surroundingtemperature obliged them to consume a certain quantity.Strictly speaking, they could do without its _light_, but notwithout its _heat_. Fortunately the caloric generated by Reiset'sand Regnaut's apparatus raised the temperature of the interiorof the projectile a little, and without much expenditure theywere able to keep it bearable.
But observations had now become very difficult. the dampness ofthe projectile was condensed on the windows and congealed immediately.This cloudiness had to be dispersed continually. In any casethey might hope to be able to discover some phenomena of thehighest interest.
But up to this time the disc remained dumb and dark. It did notanswer the multiplicity of questions put by these ardent minds;a matter which drew this reflection from Michel, apparently ajust one:
"If ever we begin this journey over again, we shall do well tochoose the time when the moon is at the full."
"Certainly," said Nicholl, "that circumstance will be more favorable.I allow that the moon, immersed in the sun's rays, will not bevisible during the transit, but instead we should see the earth,which would be full. And what is more, if we were drawn round themoon, as at this moment, we should at least have the advantage ofseeing the invisible part of her disc magnificently lit."
"Well said, Nicholl," replied Michel Ardan. "What do youthink, Barbicane?"
"I think this," answered the grave president: "If ever we beginthis journey again, we shall start at the same time and underthe same conditions. Suppose we had attained our end, would itnot have been better to have found continents in broad daylightthan a country plunged in utter darkness? Would not our firstinstallation have been made under better circumstances?Yes, evidently. As to the invisible side, we could have visitedit in our exploring expeditions on the lunar globe. So that thetime of the full moon was well chosen. But we ought to havearrived at the end; and in order to have so arrived, we oughtto h
ave suffered no deviation on the road."
"I have nothing to say to that," answered Michel Ardan."Here is, however, a good opportunity lost of observing theother side of the moon."
But the projectile was now describing in the shadow thatincalculable course which no sight-mark would allow themto ascertain. Had its direction been altered, either by theinfluence of the lunar attraction, or by the action of someunknown star? Barbicane could not say. But a change had takenplace in the relative position of the vehicle; and Barbicaneverified it about four in the morning.
The change consisted in this, that the base of the projectilehad turned toward the moon's surface, and was so held by aperpendicular passing through its axis. The attraction, that isto say the weight, had brought about this alteration. The heaviestpart of the projectile inclined toward the invisible disc as if itwould fall upon it.
Was it falling? Were the travelers attaining that much desired end?No. And the observation of a sign-point, quite inexplicable initself, showed Barbicane that his projectile was not nearing themoon, and that it had shifted by following an almost concentric curve.
This point of mark was a luminous brightness, which Nichollsighted suddenly, on the limit of the horizon formed by theblack disc. This point could not be confounded with a star.It was a reddish incandescence which increased by degrees, adecided proof that the projectile was shifting toward it andnot falling normally on the surface of the moon.
"A volcano! it is a volcano in action!" cried Nicholl; "adisemboweling of the interior fires of the moon! That world isnot quite extinguished."
"Yes, an eruption," replied Barbicane, who was carefullystudying the phenomenon through his night glass. "What shouldit be, if not a volcano?"
"But, then," said Michel Ardan, "in order to maintain thatcombustion, there must be air. So the atmosphere does surroundthat part of the moon."
"Perhaps so," replied Barbicane, "but not necessarily.
The volcano, by the decomposition of certain substances, canprovide its own oxygen, and thus throw flames into space. It seemsto me that the deflagration, by the intense brilliancy of thesubstances in combustion, is produced in pure oxygen. We mustnot be in a hurry to proclaim the existence of a lunar atmosphere."
The fiery mountain must have been situated about the
[email protected] southlatitude on the invisible part of the disc; but, to Barbicane'sgreat displeasure, the curve which the projectile was describingwas taking it far from the point indicated by the eruption.Thus he could not determine its nature exactly. Half an hourafter being sighted, this luminous point had disappeared behindthe dark horizon; but the verification of this phenomenon wasof considerable consequence in their selenographic studies.It proved that all heat had not yet disappeared from the bowelsof this globe; and where heat exists, who can affirm that thevegetable kingdom, nay, even the animal kingdom itself, has notup to this time resisted all destructive influences? The existenceof this volcano in eruption, unmistakably seen by these earthlysavants, would doubtless give rise to many theories favorableto the grave question of the habitability of the moon.
Barbicane allowed himself to be carried away by these reflections.He forgot himself in a deep reverie in which the mysteriousdestiny of the lunar world was uppermost. He was seeking tocombine together the facts observed up to that time, when a newincident recalled him briskly to reality. This incident was morethan a cosmical phenomenon; it was a threatened danger, theconsequence of which might be disastrous in the extreme.
Suddenly, in the midst of the ether, in the profound darkness, anenormous mass appeared. It was like a moon, but an incandescentmoon whose brilliancy was all the more intolerable as it cutsharply on the frightful darkness of space. This mass, of acircular form, threw a light which filled the projectile.The forms of Barbicane, Nicholl, and Michel Ardan, bathed inits white sheets, assumed that livid spectral appearance whichphysicians produce with the fictitious light of alcoholimpregnated with salt.
"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 distanceof at most 200 miles, ought, according to Barbicane, to have adiameter of 2,000 yards. It advanced at a speed of about onemile and a half per second. It cut the projectile's path andmust reach it in some minutes. As it approached it grew toenormous proportions.
Imagine, if possible, the situation of the travelers! It isimpossible to describe it. In spite of their courage, their_sang-froid_, their carelessness of danger, they were mute,motionless with stiffened limbs, a prey to frightful terror.Their projectile, the course of which they could not alter, wasrushing straight on this ignited mass, more intense than theopen mouth of an oven. It seemed as though they were beingprecipitated toward an abyss of fire.
Barbicane had seized the hands of his two companions, and allthree looked through their half-open eyelids upon that asteroidheated to a white heat. If thought was not destroyed withinthem, if their brains still worked amid all this awe, they musthave given themselves up for lost.
Two minutes after the sudden appearance of the meteor (to themtwo centuries of anguish) the projectile seemed almost about tostrike it, when the globe of fire burst like a bomb, but withoutmaking any noise in that void where sound, which is but theagitation of the layers of air, could not be generated.
Nicholl uttered a cry, and he and his companions rushed tothe scuttle. What a sight! What pen can describe it?What palette is rich enough in colors to reproduce so magnificenta spectacle?
It was like the opening of a crater, like the scattering of animmense conflagration. Thousands of luminous fragments lit upand irradiated space with their fires. Every size, every color,was there intermingled. There were rays of yellow and paleyellow, red, green, gray-- a crown of fireworks of all colors.Of the enormous and much-dreaded globe there remained nothingbut these fragments carried in all directions, now becomeasteroids in their turn, some flaming like a sword, somesurrounded by a whitish cloud, and others leaving behind themtrains of brilliant cosmical dust.
These incandescent blocks crossed and struck each other,scattering still smaller fragments, some of which struckthe projectile. Its left scuttle was even cracked by aviolent shock. It seemed to be floating amid a hail ofhowitzer shells, the smallest of which might destroyit instantly.
The light which saturated the ether was so wonderfully intense,that Michel, drawing Barbicane and Nicholl to his window,exclaimed, "The invisible moon, visible at last!"
And through a luminous emanation, which lasted some seconds, thewhole three caught a glimpse of that mysterious disc which the eyeof man now saw for the first time. What could they distinguishat a distance which they could not estimate? Some lengthenedbands along the disc, real clouds formed in the midst of a veryconfined atmosphere, from which emerged not only all the mountains,but also projections of less importance; its circles, its yawningcraters, as capriciously placed as on the visible surface.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 surfaceof the continents, large dark masses, looking like immense forestsunder the rapid illumination of a brilliance.
Was it an illusion, a mistake, an optical illusion? Could theygive a scientific assent to an observation so superficially obtained?Dared they pronounce upon the question of its habitability afterso slight a glimpse of the invisible disc?
But the lightnings in space subsided by degrees; its accidentalbrilliancy died away; the asteroids dispersed in differentdirections and were extinguished in the distance.
The ether returned to its accustomed darkness; the stars, eclipsedfor a moment, again twinkled in the firmament, and the disc, sohastily discerned, was again buried in impenetrable night.