round the moon-第25章
按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
than time enough to allow the instrument to fall to the level of
the surrounding temperature。 Then it was rapidly pulled in。
Barbicane calculated the quantity of spirits of wine overflowed
into the little vial soldered to the lower part of the
instrument； and said：
〃A hundred and forty degrees Centigrade ＇4＇ below zero！〃
＇4＇ 218 degrees Fahrenheit below zero。
M。 Pouillet was right and Fourier wrong。 That was the undoubted
temperature of the starry space。 Such is； perhaps； that of the
lunar continents； when the orb of night has lost by radiation
all the heat which fifteen days of sun have poured into her。
CHAPTER XV
HYPERBOLA OR PARABOLA
We may； perhaps； be astonished to find Barbicane and his
companions so little occupied with the future reserved for them
in their metal prison which was bearing them through the
infinity of space。 Instead of asking where they were going；
they passed their time making experiments； as if they had been
quietly installed in their own study。
We might answer that men so strong…minded were above such
anxieties that they did not trouble themselves about such
trifles and that they had something else to do than to
occupy 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； an
aeronaut can give a vertical motion to his balloon。 They； on
the contrary； had no power over their vehicle。 Every maneuver
was forbidden。 Hence the inclination to let things alone； or as
the sailors say； 〃let her run。〃
Where did they find themselves at this moment； at eight o'clock in
the morning of the day called upon the earth the 6th of December？
Very certainly in the neighborhood of the moon； and even near
enough for her to look to them like an enormous black screen upon
the firmament。 As to the distance which separated them； it was
impossible to estimate it。 The projectile； held by some
unaccountable force； had been within four miles of grazing the
satellite's north pole。
But since entering the cone of shadow these last two hours； had
the distance increased or diminished？ Every point of mark was
wanting by which to estimate both the direction and the speed of
the projectile。
Perhaps it was rapidly leaving the disc； so that it would soon
quit the pure shadow。 Perhaps； again； on the other hand； it
might be nearing it so much that in a short time it might strike
some high point on the invisible hemisphere； which would doubtlessly
have ended the journey much to the detriment of the travelers。
A discussion arose on this subject； and Michel Ardan； always
ready with an explanation； gave it as his opinion that the
projectile； held by the lunar attraction； would end by falling
on the surface of the terrestrial globe like an aerolite。
〃First of all； my friend；〃 answered Barbicane； 〃every aerolite
does not fall to the earth； it is only a small proportion which
do so； and if we had passed into an aerolite； it does not necessarily
follow 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 shooting
stars rush through the sky by thousands at certain seasons？〃
〃Yes。〃
〃Well； these stars； or rather corpuscles； only shine when they
are heated by gliding over the atmospheric layers。 Now； if
they enter the atmosphere； they pass at least within forty
miles of the earth； but they seldom fall upon it。 The same with
our projectile。 It may approach very near to the moon； and not
yet fall upon it。〃
〃But then；〃 asked Michel； 〃I shall be curious to know how our
erring vehicle 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 it will follow one or the other according to the speed with
which it is animated； 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 the parabola； and with a greater the hyperbola。〃
〃I like those grand words；〃 exclaimed Michel Ardan； 〃one knows
directly what they mean。 And pray what is your parabola； if
you please？〃
〃My friend；〃 answered the captain； 〃the parabola is a curve of
the second order； the result of the section of a cone
intersected 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 by
a bomb launched from a mortar。〃
〃Perfect！ And the hyperbola？〃
〃The hyperbola； Michel； is a curve of the second order； produced
by the intersection of a conic surface and a plane parallel to
its 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； as
if they had told him of some serious event。 〃What I particularly
like in your definition of the hyperbola （I was going to say
hyperblague） is that it is still more obscure than the word you
pretend to define。〃
Nicholl and Barbicane cared little for Michel Ardan's fun。
They were deep in a scientific discussion。 What curve would
the projectile follow？ was their hobby。 One maintained the
hyperbola； the other the parabola。 They gave each other reasons
bristling with _x_。 Their arguments were couched in language
which made Michel jump。 The discussion was hot； and neither
would 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
hyperbolas at each other's heads？ I want to understand the only
interesting question in the whole affair。 We shall follow one
or the 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
prolonged indefinitely。〃
〃Ah； savants！〃 cried Michel； 〃and what are either the one or the
other to us from the moment we know that they equally lead us
into infinite space？〃
Barbicane and Nicholl could not forbear smiling。 They had just
been creating 〃art for art's sake。〃 Never had so idle a question
been raised at such an inopportune moment。 The sinister truth
remained 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 was
to economize the gas； the excessive lowness of the surrounding
temperature obliged them to consume a certain quantity。
Strictly speaking； they could do without its _light_； but not
without its _heat_。 Fortunately the caloric generated by Reiset's
and Regnaut's apparatus raised the temperature of the interior
of the projectile a little； and without much expenditure they
were able to keep it bearable。
But observations had now become very difficult。 the dampness of
the projectile was condensed on the windows and congealed immediately。
This cloudiness had to be dispersed continually。 In any case
they might hope to be able to discover some phenomena of the
highest interest。
But up to this time the disc remained dumb and dark。 It did not
answer the multiplicity of questions put by these ardent minds；
a matter which drew this reflection from Michel； apparently a
just one：
〃If ever we begin this journey over again； we shall do well to
choose 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 be
visible during the transit； but instead we should see the earth；
which would be full。 And what is more；
