journey　in　order　to　form　an　opinion　on　the　past　habitability　of
  our　satellite；　but　I　will　add　that　our　personal　observations
  only　confirm　me　in　this　opinion。　　I　believe；　indeed　I　affirm；
  that　the　moon　has　been　inhabited　by　a　human　race　organized　like
  our　own；　that　she　has　produced　animals　anatomically　formed　like
  the　terrestrial　animals：　　but　I　add　that　these　races；　human　and
  animal；　have　had　their　day；　and　are　now　forever　extinct！〃
  〃Then；〃　asked　Michel；　〃the　moon　must　be　older　than　the　earth？〃
  〃No！〃　said　Barbicane　decidedly；　〃but　a　world　which　has　grown　old
  quicker；　and　whose　formation　and　deformation　have　been　more　rapid。
  Relatively；　the　organizing　force　of　matter　has　been　much　more
  violent　in　the　interior　of　the　moon　than　in　the　interior　of　the
  terrestrial　globe。　　The　actual　state　of　this　cracked；　twisted；
  and　burst　disc　abundantly　proves　this。　　The　moon　and　the　earth
  were　nothing　but　gaseous　masses　originally。　　These　gases　have
  passed　into　a　liquid　state　under　different　influences；　and　the
  solid　masses　have　been　formed　later。　But　most　certainly　our
  sphere　was　still　gaseous　or　liquid；　when　the　moon　was　solidified
  by　cooling；　and　had　become　habitable。〃
  〃I　believe　it；〃　said　Nicholl。
  〃Then；〃　continued　Barbicane；　〃an　atmosphere　surrounded　it；　the
  waters　contained　within　this　gaseous　envelope　could　not　evaporate。
  Under　the　influence　of　air；　water；　light；　solar　heat；　and　central
  heat；　vegetation　took　possession　of　the　continents　prepared　to
  receive　it；　and　certainly　life　showed　itself　about　this　period；
  for　nature　does　not　expend　herself　in　vain；　and　a　world　so
  wonderfully　formed　for　habitation　must　necessarily　be　inhabited。〃
  〃But；〃　said　Nicholl；　〃many　phenomena　inherent　in　our　satellite
  might　cramp　the　expansion　of　the　animal　and　vegetable　kingdom。
  For　example；　its　days　and　nights　of　354　hours？〃
  〃At　the　terrestrial　poles　they　last　six　months；〃　said　Michel。
  〃An　argument　of　little　value；　since　the　poles　are　not　inhabited。〃
  〃Let　us　observe；　my　friends；〃　continued　Barbicane；　〃that　if　in
  the　actual　state　of　the　moon　its　long　nights　and　long　days
  created　differences　of　temperature　insupportable　to
  organization；　it　was　not　so　at　the　historical　period　of　time。
  The　atmosphere　enveloped　the　disc　with　a　fluid　mantle；　vapor
  deposited　itself　in　the　shape　of　clouds；　this　natural　screen
  tempered　the　ardor　of　the　solar　rays；　and　retained　the
  nocturnal　radiation。　　Light；　like　heat；　can　diffuse　itself　in
  the　air；　hence　an　equality　between　the　influences　which　no　longer
  exists；　now　that　atmosphere　has　almost　entirely　disappeared。
  And　now　I　am　going　to　astonish　you。〃
  〃Astonish　us？〃　said　Michel　Ardan。
  〃I　firmly　believe　that　at　the　period　when　the　moon　was　inhabited；
  the　nights　and　days　did　not　last　354　hours！〃
  〃And　why？〃　asked　Nicholl　quickly。
  〃Because　most　probably　then　the　rotary　motion　of　the　moon　upon
  her　axis　was　not　equal　to　her　revolution；　an　equality　which
  presents　each　part　of　her　disc　during　fifteen　days　to　the　action
  of　the　solar　rays。〃
  〃Granted；〃　replied　Nicholl；　〃but　why　should　not　these　two
  motions　have　been　equal；　as　they　are　really　so？〃
  〃Because　that　equality　has　only　been　determined　by
  terrestrial　attraction。　　And　who　can　say　that　this　attraction
  was　powerful　enough　to　alter　the　motion　of　the　moon　at　that
  period　when　the　earth　was　still　fluid？〃
  〃Just　so；〃　replied　Nicholl；　〃and　who　can　say　that　the　moon　has
  always　been　a　satellite　of　the　earth？〃
  〃And　who　can　say；〃　exclaimed　Michel　Ardan；　〃that　the　moon　did
  not　exist　before　the　earth？〃
  Their　imaginations　carried　them　away　into　an　indefinite　field
  of　hypothesis。　　Barbicane　sought　to　restrain　them。
  〃Those　speculations　are　too　high；〃　said　he；　〃problems
  utterly　insoluble。　　Do　not　let　us　enter　upon　them。　　Let　us　only
  admit　the　insufficiency　of　the　primordial　attraction；　and　then
  by　the　inequality　of　the　two　motions　of　rotation　and　revolution；
  the　days　and　nights　could　have　succeeded　each　other　on　the　moon
  as　they　succeed　each　other　on　the　earth。　　Besides；　even　without
  these　conditions；　life　was　possible。〃
  〃And　so；〃　asked　Michel　Ardan；　〃humanity　has　disappeared　from
  the　moon？〃
  〃Yes；〃　replied　Barbicane；　〃after　having　doubtless　remained
  persistently　for　millions　of　centuries；　by　degrees　the
  atmosphere　becoming　rarefied；　the　disc　became　uninhabitable；　as
  the　terrestrial　globe　will　one　day　become　by　cooling。〃
  〃By　cooling？〃
  〃Certainly；〃　replied　Barbicane；　〃as　the　internal　fires　became
  extinguished；　and　the　incandescent　matter　concentrated　itself；
  the　lunar　crust　cooled。　　By　degrees　the　consequences　of　these
  phenomena　showed　themselves　in　the　disappearance　of　organized
  beings；　and　by　the　disappearance　of　vegetation。　　Soon　the
  atmosphere　was　rarefied；　probably　withdrawn　by　terrestrial
  attraction；　then　aerial　departure　of　respirable　air；　and
  disappearance　of　water　by　means　of　evaporation。　　At　this　period
  the　moon　becoming　uninhabitable；　was　no　longer　inhabited。
  It　was　a　dead　world；　such　as　we　see　it　to…day。〃
  〃And　you　say　that　the　same　fate　is　in　store　for　the　earth？〃
  〃Most　probably。〃
  〃But　when？〃
  〃When　the　cooling　of　its　crust　shall　have　made　it　uninhabitable。〃
  〃And　have　they　calculated　the　time　which　our　unfortunate　sphere
  will　take　to　cool？〃
  〃Certainly。〃
  〃And　you　know　these　calculations？〃
  〃Perfectly。〃
  〃But　speak；　then；　my　clumsy　savant；〃　exclaimed　Michel　Ardan；
  〃for　you　make　me　boil　with　impatience！〃
  〃Very　well；　my　good　Michel；〃　replied　Barbicane　quietly；　〃we　know
  what　diminution　of　temperature　the　earth　undergoes　in　the　lapse
  of　a　century。　　And　according　to　certain　calculations；　this　mean
  temperature　will　after　a　period　of　400；000　years；　be　brought
  down　to　zero！〃
  〃Four　hundred　thousand　years！〃　exclaimed　Michel。　　〃Ah！　　I
  breathe　again。　　Really　I　was　frightened　to　hear　you；　I　imagined
  that　we　had　not　more　than　50；000　years　to　live。〃
  Barbicane　and　Nicholl　could　not　help　laughing　at　their
  companion's　uneasiness。　　Then　Nicholl；　who　wished　to　end　the
  discussion；　put　the　second　question；　which　had　just　been
  considered　again。
  〃Has　the　moon　been　inhabited？〃　he　asked。
  The　answer　was　unanimously　in　the　affirmative。　　But　during　this
  discussion；　fruitful　in　somewhat　hazardous　theories；　the
  projectile　was　rapidly　leaving　the　moon：　the　lineaments　faded
  away　from　the　travelers'　eyes；　mountains　were　confused　in　the
  distance；　and　of　all　the　wonderful；　strange；　and　fantastical
  form　of　the　earth's　satellite；　there　soon　remained　nothing　but
  the　imperishable　remembrance。
  CHAPTER　XIX
  A　STRUGGLE　AGAINST　THE　IMPOSSIBLE
  For　a　long　time　Barbicane　and　his　companions　looked　silently　and
  sadly　upon　that　world　which　they　had　only　seen　from　a　distance；
  as　Moses　saw　the　land　of　Canaan；　and　which　they　were　leaving
  without　a　possibility　of　ever　returning　to　it。　　The　projectile's
  position　with　regard　to　the　moon　had　altered；　and　the　base　was
  now　turned　to　the　earth。
  This　change；　which　Barbicane　verified；　did　not　fail　to　surprise　them。
  If　the　projectile　was　to　gravitate　round　the　satellite　in　an
  elliptical　orbit；　why　was　not　its　heaviest　part　turned　toward　it；
  as　the　moon　turns　hers　to　the　earth？　　That　was　a　difficult　point。
  In　watching　the　course　of　the　projectile　they　could　see　that　on
  leaving　the　moon　it　followed　a　course　analogous　to　that　traced
  in　approaching　her。　　It　was　describing　a　very　long　ellipse；
  which　would　most　likely　extend　to　the　point　of　equal　attraction；
  where　the　influences　of　the　earth　and　its　satellite　are　neutralized。
  Such　was　the　conclusion　which　Barbicane　very　justly　drew　from
  facts　already　observed；　a　conviction　which　his　two　friends
  shared　with　him。
  〃And　when　arrived　at　this　dead　point；　what　will　become　of　us？〃
  asked　Michel　Ardan。
  〃We　don't　know；〃　replied　Barbicane。
  〃But　one　can　draw　some　hypotheses；　I　suppose？〃
  〃Two；〃　answered　Barbicane；　〃either　the　projectile's　speed　will
  be　insufficient；　and　it　will　remain　forever　immovable　on　this
  line　of　double　attraction〃
  〃I　prefer　the　other　hypothesis；　whatever　it　may　be；〃　interrupted　Michel。
  〃Or；〃　continued　Barbicane；　〃its　speed　will　be　sufficient；　and　it
  will　continue　its　elliptical　course；　to　gravitate　forever　around
  the　orb　of　night。〃
  〃A　revolution　not　at　all　consoling；〃　said　Michel；　〃to　pass　to
  the　state　of　humble　servants　to　a　moon　whom　we　are　accustomed　to
  look　upon　as　our　own　handmaid。　　So　that　is　the　fate　in　store　for　us？〃
  Neither　Barbicane　nor　Nicholl　answered。
  〃You　do　not　answer；〃　continued　Michel　impatiently。
  〃There　is　nothing　to　answer；〃　said　Nicholl。
  〃Is　there　nothing　to　try？〃
  〃No；〃　answered　Barbicane。　　〃Do　you　pretend　to　fight　against
  the　impossible？〃
  〃Why　not？　　Do　one　Frenchman　and　two　Americans　shrink　from　such
  a　word？〃
  〃But　what　would　you　do？〃
  〃Subdue　this　motion　which　is　bearing　us　away。〃
  〃Subdue　it？〃
  〃Yes；〃　continued　Michel；　getting　animated；　〃or　else　alter　it；
  and　employ　it　to　the　accomplishment　of　our　own　ends。〃
  〃And　how？〃
  〃That　is　your　affair。　　If　artillerymen　are　not　masters　of　their
  projectile　they　are　not　artillerymen。　　If　the　projectile　is　to
  command　the　gunner；　we　had　better　ram　the　gunner　into　the　gun。
  My　faith！　fine　savants！　who　do　not　know　what　is　to