round the moon-第7部分

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〃You　mean　to　say；〃　replied　Barbicane；　〃to　attain　that　neutral
point　where　the　terrestrial　and　lunar　attractions　are　equal；
for；　starting　from　that　point；　situated　about　nine…tenths　of　the
distance　traveled　over；　the　projectile　would　simply　fall　upon
the　moon；　on　account　of　its　weight。〃

〃So　be　it；〃　said　Michel；　〃but；　once　more；　how　could　they
calculate　the　initiatory　speed？〃

〃Nothing　can　be　easier；〃　replied　Barbicane。

〃And　you　knew　how　to　make　that　calculation？〃　asked　Michel　Ardan。

〃Perfectly。　　Nicholl　and　I　would　have　made　it；　if　the
observatory　had　not　saved　us　the　trouble。〃

〃Very　well；　old　Barbicane；〃　replied　Michel；　〃they　might　have　cut
off　my　head；　beginning　at　my　feet；　before　they　could　have　made
me　solve　that　problem。〃

〃Because　you　do　not　know　algebra；〃　answered　Barbicane　quietly。

〃Ah；　there　you　are；　you　eaters　of　_x_^1；　you　think　you　have　said
all　when　you　have　said　‘Algebra。'〃

〃Michel；〃　said　Barbicane；　〃can　you　use　a　forge　without　a　hammer；
or　a　plow　without　a　plowshare？〃

〃Hardly。〃

〃Well；　algebra　is　a　tool；　like　the　plow　or　the　hammer；　and　a
good　tool　to　those　who　know　how　to　use　it。〃

〃Seriously？〃

〃Quite　seriously。〃

〃And　can　you　use　that　tool　in　my　presence？〃

〃If　it　will　interest　you。〃

〃And　show　me　how　they　calculated　the　initiatory　speed　of　our　car？〃

〃Yes；　my　worthy　friend；　taking　into　consideration　all　the
elements　of　the　problem；　the　distance　from　the　center　of　the
earth　to　the　center　of　the　moon；　of　the　radius　of　the　earth；　of
its　bulk；　and　of　the　bulk　of　the　moon；　I　can　tell　exactly　what
ought　to　be　the　initiatory　speed　of　the　projectile；　and　that　by
a　simple　formula。〃

〃Let　us　see。〃

〃You　shall　see　it；　only　I　shall　not　give　you　the　real　course
drawn　by　the　projectile　between　the　moon　and　the　earth　in
considering　their　motion　round　the　sun。　　No；　I　shall　consider
these　two　orbs　as　perfectly　motionless；　which　will　answer　all
our　purpose。〃

〃And　why？〃

〃Because　it　will　be　trying　to　solve　the　problem　called　‘the
problem　of　the　three　bodies；'　for　which　the　integral　calculus　is
not　yet　far　enough　advanced。〃

〃Then；〃　said　Michel　Ardan；　in　his　sly　tone；　〃mathematics　have
not　said　their　last　word？〃

〃Certainly　not；〃　replied　Barbicane。

〃Well；　perhaps　the　Selenites　have　carried　the　integral　calculus
farther　than　you　have；　and；　by　the　bye；　what　is　this
‘integral　calculus？'〃

〃It　is　a　calculation　the　converse　of　the　differential；〃　replied
Barbicane　seriously。

〃Much　obliged；　it　is　all　very　clear；　no　doubt。〃

〃And　now；〃　continued　Barbicane；　〃a　slip　of　paper　and　a　bit　of
pencil；　and　before　a　half…hour　is　over　I　will　have　found　the
required　formula。〃

Half　an　hour　had　not　elapsed　before　Barbicane；　raising　his　head；
showed　Michel　Ardan　a　page　covered　with　algebraical　signs；　in
which　the　general　formula　for　the　solution　was　contained。

〃Well；　and　does　Nicholl　understand　what　that　means？〃

〃Of　course；　Michel；〃　replied　the　captain。　　〃All　these　signs；
which　seem　cabalistic　to　you；　form　the　plainest；　the　clearest；
and　the　most　logical　language　to　those　who　know　how　to　read　it。〃

〃And　you　pretend；　Nicholl；〃　asked　Michel；　〃that　by　means　of
these　hieroglyphics；　more　incomprehensible　than　the　Egyptian
Ibis；　you　can　find　what　initiatory　speed　it　was　necessary　to
give　the　projectile？〃

〃Incontestably；〃　replied　Nicholl；　〃and　even　by　this　same　formula
I　can　always　tell　you　its　speed　at　any　point　of　its　transit。〃

〃On　your　word？〃

〃On　my　word。〃

〃Then　you　are　as　cunning　as　our　president。〃

〃No；　Michel；　the　difficult　part　is　what　Barbicane　has　done；　that
is；　to　get　an　equation　which　shall　satisfy　all　the　conditions　of
the　problem。　　The　remainder　is　only　a　question　of　arithmetic；
requiring　merely　the　knowledge　of　the　four　rules。〃

〃That　is　something！〃　replied　Michel　Ardan；　who　for　his　life
could　not　do　addition　right；　and　who　defined　the　rule　as　a
Chinese　puzzle；　which　allowed　one　to　obtain　all　sorts　of　totals。

〃The　expression　_v_　zero；　which　you　see　in　that　equation；　is　the
speed　which　the　projectile　will　have　on　leaving　the　atmosphere。〃

〃Just　so；〃　said　Nicholl；　〃it　is　from　that　point　that　we　must
calculate　the　velocity；　since　we　know　already　that　the　velocity
at　departure　was　exactly　one　and　a　half　times　more　than　on
leaving　the　atmosphere。〃

〃I　understand　no　more；〃　said　Michel。

〃It　is　a　very　simple　calculation；〃　said　Barbicane。

〃Not　as　simple　as　I　am；〃　retorted　Michel。

〃That　means；　that　when　our　projectile　reached　the　limits　of　the
terrestrial　atmosphere　it　had　already　lost　one…third　of　its
initiatory　speed。〃

〃As　much　as　that？〃

〃Yes；　my　friend；　merely　by　friction　against　the　atmospheric　strata。
You　understand　that　the　faster　it　goes　the　more　resistance　it　meets
with　from　the　air。〃

〃That　I　admit；〃　answered　Michel；　〃and　I　understand　it；
although　your　x's　and　zero's；　and　algebraic　formula；　are
rattling　in　my　head　like　nails　in　a　bag。〃

〃First　effects　of　algebra；〃　replied　Barbicane；　〃and　now；　to
finish；　we　are　going　to　prove　the　given　number　of　these
different　expressions；　that　is；　work　out　their　value。〃

〃Finish　me！〃　replied　Michel。

Barbicane　took　the　paper；　and　began　to　make　his　calculations
with　great　rapidity。　　Nicholl　looked　over　and　greedily　read　the
work　as　it　proceeded。

〃That's　it！　that's　it！〃　at　last　he　cried。

〃Is　it　clear？〃　asked　Barbicane。

〃It　is　written　in　letters　of　fire；〃　said　Nicholl。

〃Wonderful　fellows！〃　muttered　Ardan。

〃Do　you　understand　it　at　last？〃　asked　Barbicane。

〃Do　I　understand　it？〃　cried　Ardan；　〃my　head　is　splitting　with　it。〃

〃And　now；〃　said　Nicholl；　〃to　find　out　the　speed　of　the
projectile　when　it　leaves　the　atmosphere；　we　have　only　to
calculate　that。〃

The　captain；　as　a　practical　man　equal　to　all　difficulties；　began
to　write　with　frightful　rapidity。　　Divisions　and　multiplications
grew　under　his　fingers；　the　figures　were　like　hail　on　the　white　page。
Barbicane　watched　him；　while　Michel　Ardan　nursed　a　growing　headache
with　both　hands。

〃Very　well？〃　asked　Barbicane；　after　some　minutes'　silence。

〃Well！〃　replied　Nicholl；　every　calculation　made；　_v_　zero；　that
is　to　say；　the　speed　necessary　for　the　projectile　on　leaving　the
atmosphere；　to　enable　it　to　reach　the　equal　point　of　attraction；
ought　to　be〃

〃Yes？〃　said　Barbicane。

〃Twelve　thousand　yards。〃

〃What！〃　exclaimed　Barbicane；　starting；　〃you　say〃

〃Twelve　thousand　yards。〃

〃The　devil！〃　cried　the　president；　making　a　gesture　of　despair。

〃What　is　the　matter？〃　asked　Michel　Ardan；　much　surprised。

〃What　is　the　matter！　why；　if　at　this　moment　our　speed　had
already　diminished　one…third　by　friction；　the　initiatory　speed
ought　to　have　been〃

〃Seventeen　thousand　yards。〃

〃And　the　Cambridge　Observatory　declared　that　twelve　thousand
yards　was　enough　at　starting；　and　our　projectile；　which　only
started　with　that　speed〃

〃Well？〃　asked　Nicholl。

〃Well；　it　will　not　be　enough。〃

〃Good。〃

〃We　shall　not　be　able　to　reach　the　neutral　point。〃

〃The　deuce！〃

〃We　shall　not　even　get　halfway。〃

〃In　the　name　of　the　projectile！〃　exclaimed　Michel　Ardan；　jumping
as　if　it　was　already　on　the　point　of　striking　the　terrestrial　globe。

〃And　we　shall　fall　back　upon　the　earth！〃





CHAPTER　V


THE　COLD　OF　SPACE


This　revelation　came　like　a　thunderbolt。　　Who　could　have
expected　such　an　error　in　calculation？　　Barbicane　would　not
believe　it。　　Nicholl　revised　his　figures：　they　were　exact。
As　to　the　formula　which　had　determined　them；　they　could　not
suspect　its　truth；　it　was　evident　that　an　initiatory　velocity　of
seventeen　thousand　yards　in　the　first　second　was　necessary　to
enable　them　to　reach　the　neutral　point。

The　three　friends　looked　at　each　other　silently。　　There　was　no
thought　of　breakfast。　　Barbicane；　with　clenched　teeth；　knitted
brows；　and　hands　clasped　convulsively；　was　watching　through
the　window。　　Nicholl　had　crossed　his　arms；　and　was　examining
his　calculations。　　Michel　Ardan　was　muttering：

〃That　is　just　like　these　scientific　men：　　they　never　do　anything　else。
I　would　give　twenty　pistoles　if　we　could　fall　upon　the　Cambridge
Observatory　and　crush　it；　together　with　the　whole　lot　of　dabblers
in　figures　which　it　contains。〃

Suddenly　a　thought　struck　the　captain；　which　he　at　once
communicated　to　Barbicane。

〃Ah！〃　said　he；　〃it　is　seven　o'clock　in　the　morning；　we　have
already　been　gone　thirty…two　hours；　more　than　half　our　passage
is　over；　and　we　are　not　falling　that　I　am　aware　of。〃

Barbicane　did　not　answer；　but　after　a　rapid　glance　at　the
captain；　took　a　pair　of　compasses　wherewith　to　measure　the
angular　distance　of　the　terrestrial　globe；　then　from　the　lower
window　he　took　an　exact　observation；　and　noticed　that　the
projectile　was　apparently　stationary。　　Then　rising　and　wiping
his　forehead；　on　which　large　drops　of　perspiration　were
standing；　he　put　some　figures　on　paper。　　Nicholl　understood　that
the　president　was　deducting　from　the　terrestrial　diameter　the
projectile's　distance　from　the　earth。　　He　watched　him　anxiously。

〃No；〃　exclaimed　Barbicane；　after　some　moments；　〃no；　we　are　not
falling！　no；　we　are　already　more　than　50；000　leagues　from　the　earth。
We　have　passed　the　point　at　which　the　projectile　would　have　stopped
if　its　speed　had　only　been　12；000　yards　at　starting。　　We　are　still
going　up。〃

〃That　is　evident；〃　replied　Nicholl；　〃and　we　must　conclude　that
our　initial　speed；　under　the　power　of　the　400；000　pounds　of
gun…cotton；　must　have　exceeded　the　required　12；000　yards。
Now　I　can　understand　how；　after　thirteen　minutes　only；　we　met　the
second　satellite；　which　gravitates　round　the　earth　at　more　than
2；000　leagues'　distance。〃

〃And　this　explanation　is　the　more　probable；〃　added　Barbicane；
〃Because；　in　throwing　off　the　water　enclosed　between　its
partition…breaks；　the　projectile　found　itself　lightened　of　a
considerable　weight。〃

〃Just　so；〃　said　Nicholl。

〃Ah；　my　brave　Nicholl；　we　are　saved！〃

〃Very　well　then；〃　said　Michel　Ardan　quietly；　〃as　we　are　safe；
let　us　have　breakfast。〃

Nicholl　was　not　mistaken。　　The　initial　speed　had　been；　very
fortunately；　much　above　that　estimated　by　the　Cambridge
Observatory；　but　the　Cambridge　Observatory　had　nevertheless　made
a　mistake。

The　travelers；　recovered　from　this　fal