Afterthisthetravellersflewnorthwardatgreatspeedintheupperregionsoftheair,fortheywereanxioustohastentheirjourney。Theyfoundnothingbutunbrokensea,andnottilltheyreachedlatitudeeighty—sevenwasthereasignofice。Theythensawsomesmallbergsandfieldice,butinnogreatquantities。
Astheiroutsidethermometer,whenjustabovetheplacidwater——fortherewerenowaveshere——registeredtwenty—onedegreesFahrenheit,theyaccountedforthisscarcityoficebytheabsenceoflandonwhichfreshwatercouldfreeze,andbythefactthatitwasnotcoldenoughtocongealtheverysaltsea—water。
Finallytheyreachedanotherarchipelagoafewhundredmilesinextent,thelargerislandsofwhichwerecoveredwithasheetofice,attheedgesofwhichsmallicebergswerebeingformedbybreakingoffandslowlyfloating。Findingasmallislandonwhichthecoatingwasthin,theygroundedtheCallisto,andsteppedoutforthefirsttimeinseveraldays。Theairwassostillthatasmallpieceofpaperreleasedataheightofsixfeetsankslowlyandwentasstraightasthestringofaplumb—line。Thesunwasbisectedbythelineofthehorizon,andappearedtobemovingabouttheminacircle,withonlyitsupperhalfvisible。AsJupiter\'snorthernhemispherewaspassingthroughitsautumnalequinox,theyconcludedtheyhadlandedexactlyatthepole。
\"Nowtoworkonourexperiment,\"saidCortlandt。\"Iwonderhowwemaybestgetbelowthefrozensurface？\"
\"Wecanexplodeasmallquantityofdynamite,\"repliedBearwarden,\"afterwhichthediggingwillbecomparativelyeasy。\"
WhileCortlandtandBearwardenpreparedthemine,Ayraultbroughtoutapickaxe,twoshovels,andthebatteryandwireswithwhichtoignitetheexplosive。TheymadetheirpreparationswithinonehundredfeetoftheCallisto,ormuchnearerthananequivalentamountofgunpowdercouldhavebeendischarged。
\"Thisrecallsanoldlaboratoryexperiment,orratherlecture,\"
saidCortlandt,astheycompletedthearrangements,\"fortheillustrationisnotasarulecarriedout。Explodetwopoundsofpowderonanironsafeinaroomwiththewindowsclosed,andthewindowswillbeblownout,whilethesaferemainsuninjured。
Explodeanequivalentamountofdynamiteontopofthesafe,anditwillbedestroyed,whiletheglasspanesarenotevencracked。
Thisillustratesthedifferenceinrapiditywithwhichtheexplosionstakeplace。Totheintenselyrapidactionofdynamitetheairaffordsasmuchresistanceasasolidsubstance,whiletheexplosionofthepowderissoslowthattheairhastimetomoveaway;hencethedestructionofthewindowsinthefirstcase,andthesafeinthesecond。\"
Whentheyhadmovedbeyondthedangerline,Bearwarden,astheparty\'spractisingengineer,pressedthebutton,andtheexplosiondidtherest。Theyfoundthatthegroundwasfrozentoadepthofbutlittlemorethanafoot,belowwhichitbecameperceptiblywarm。Plyingtheirshovelsvigorously,theyhadsoondugtheholesodeepthatitsedgeswereabovetheirheads。Whenthefloorwastenfeetbelowthesurroundinglevelthethermometerregisteredsixty。
\"Thisisscarcelyafairtest,\"saidCortlandt,\"sincetheheatrisesandislostasfastasgivenoff。Letusthereforeclosetheopeningandseeinwhattimeitwillmeltanumberofcubicfeetofice。\"
Accordinglytheyclimbedout,threwinaboutacart—loadofice,andcoveredtheopeningwithtwooftheCallisto\'sthickrugs。
Inhalfanhouralltheicehadmelted,andinanotherhalfhourthewaterwashot。
\"Noarcticexpeditionneedfreezetodeathhere,\"saidBearwarden,\"sinceallamanwouldhavetodowouldbetoburrowafewfeettobeaswarmastoast。\"
Astheislandonwhichtheyhadlandedwasatonesideofthearchipelago,butwasitselfattheexactpole,itfollowedthatthecentreofthearchipelagowasnotthepartfarthestnorth。
Thisinameasureaccountedfortheslightthicknessoficeandsnow,fortheisobariclineswouldslope,andconsequentlywhatwindtherewaswouldflowtowardstheinteriorofthearchipelago,whosesurfacewascolderthanthesurroundingocean。
Themoistair,however,comingalmostentirelyfromthesouth,wouldlosemostofitsmoisturebycondensationinpassingovertheice—ladenland,andso,likethecloudsovertheregioneastoftheAndes,wouldhavebutlittlelefttoletfallonthisextremenorthernpart。Theblanketingeffectofagreatthicknessofsnowwouldalsocause,thelowerstrataoficetomelt,bykeepingintheheatconstantlygivenoffbythewarmplanet。
\"Ithinktherecanbenoquestion,\"saidCortlandt,\"that,asaresultofJupiter\'sgreatflatteningatthepolesandthedrawingofthecrust,whichmovesfasterinJupiter\'srotationthananyotherpart,towardstheequator,thecrustmustbeparticularlythinhere;for,wereitasthinallover,therewouldbenospaceforthecoal—beds,which,judgingfromthepurityoftheatmosphere,mustbeveryextensive。Further,wecanrecallthatthewaterinthehotspringnearwhichwealighted,whichevidentlycamefromafargreaterdepththanwehavehere,wasnotashotasthis。Theconclusionisclearthatelsewheretheinternalheatisnotasnearthesurfaceashere。\"
\"ThemoreIseeofJupiter,\"exclaimedBearwardenenthusiastically,\"themorecharmedIbecome。ItalmostexactlysupplieswhatIhavebeenconjuringupasmyideaofaperfectplanet。Itscompensationsofhighlandneartheequator,andlowwitheffectiveinternalheatatthepoles,areideal。Thegradualslopeofitscontinentalelevations,onaccountoftheirextent,willeasetheworkofoperatingrailways,andtheatmosphere\'sdensitywillbejustthethingforourflyingmachines,whileNaturehassuppliedallsourcesofpowersolavishlythatnoundertakingwillbetoogreat。Thoughlandasyet,tojudgebyourphotographs,occupiesonlyaboutoneeighthofthesurface,weknow,fromtheexperienceoftheotherplanets,thatthisisboundtoincrease;sothat,ifthehumanracecanperpetuateitselfonJupiterlongenough,itwillundoubtedlyhaveonefourthoralargerproportionforoccupation,thoughthelandalreadyupheavedcomprisesfullyfortytimestheareaofourentireglobe,which,asweknow,isstillthree—fourthswater。\"
\"SincewehavereachedwhatwemightcalltheendofJupiter,andstillhavetime,continuedAyrault,\"letusproceedtoSaturn,wherewemayfindevenstrangerthingsthanhere。Ihopedwecouldinvestigatethegreatredspot,butamconvincedwehaveseenthebeginningofoneinTwentiethCenturyArchipelago,andwhat,underfavourableconditions,willberecognizedassuchonearth。\"
Itwasjustsixterrestrialweekssincetheyhadsetout,andthereforeFebruary2donearth。
\"Itwouldbebest,inanycase,tostartfromJupiter\'sequator,\"
saidCortlandt,\"forthestraightlineweshouldmakefromthesurfaceherewouldbeatrightanglestoSaturn。Weshallprobably,inspiteofourselves,swingafewdegreesbeyondtheline,andsocangetabird\'s—eyeviewofsomeportionofthesouthernhemisphere。\"
\"AllaboardforSaturn！\"criedBearwardenenthusiastically,inhisjovialway。\"Thiswillbeajourney。\"
CHAPTERXIV。
THESCENESHIFTS。
HavingreturnedtherugstotheCallisto,theyappliedthemaximumpowerofthebatteriestorising,closedallopeningswhenthebarometerregisteredthirty,andmovedoffintospace。
WhenSeveralthousandmilesabovethepole,theydivertedpartofthepowertoattractingthenearestmoonthatwasintheplaneofJupiter\'sequator,andbythetimetheirupwardmotionhadceasedweremovingwellinitsdirection。Theirrapidmotionaidedtheworkofresistinggravity,sincetheircarhadinfactbecomeasmallmoon,revolving,likethoseofUranusorthatofNeptune,inanorbitvaryinggreatlyfromtheplaneoftheecliptic。Astheyflewsouthataheightrangingfromtwothousandtothreethousandmiles,theplanetrevolvedbeforethem,andtheyhadachanceofobtainingathoroughview。TherewerebutafewscatteredislandsonthesideoftheNorthernhemisphereoppositetothatoverwhichtheyhadreachedthepole,andinthevaryingcoloursofthewater,whichtheyattributedtotemperatureortosomesubstanceinsolution,theyrecognizedwhattheyhadalwayshearddescribedonearthasthebandsofJupiter,encirclingtheplanetwithgreatbelts,thecolourvaryingwiththelatitude。
Ataboutlatitudeforty—fivethesebandswerepurple,farthersouthlightolivegreen,andattheequatorabrownorange。
Shortlyaftertheyswungacrosstheequatortheoceanagainbecamepurple,andatthesametimeawell—definedandverybrilliantwhitespotcameintoview。Itsbrightnessshowedslightvariationsinintensity,thoughitsgeneralshaperemainedunchanged。Ithadanotherpeculiarity,inthatitpossessedafairlyrapidmotionofitsown,asitmovedeastwardacrossthesurfaceoftheocean。ItexhibitedallthephenomenaofthestormtheyhadwatchedincrossingSecretaryDeepwatersBay,butcoveredalargerarea,andwasfarmoreviolent。Theirglassesshowedthemvastsheetsofspraydrivenalongattremendousspeed,whilethesurfacewasmilkywhite。
\"This,\"saidBearwarden,pickingupabook,\"solvestomymindthemysteryofthewhitespotdescribedbytheEnglishwriterChambers,in1889,asfollows:
\"\'Duringthelastfewyearsabrilliantwhitespothasbeenvisibleontheequatorialborderofthegreatsouthernbelt。A
curiousfactinconnectionwiththisspotis,thatitmoveswithavelocityofsometwohundredandsixtymilesperhourgreaterthantheredspot。Denningobtainedonehundredandsixty—nineobservationsofthisbrightmarkingduringtheyears1880—1883,anddeterminedtheperiodasninehours,fiftyminutes,eightandsevententhsseconds（fiveandahalfminuteslessthanthatoftheredspot）。Althoughthelatterisnowsomewhatfaint,thewhitespotgivespromiseofremainingvisibleformanyyears。
Duringtheyear1886alargenumberofobservationsofJupiterweremadeattheDearbornObservatory,Chicago,U。S。,byProf。
G。W。Hough,usingtheeighteen—and—a—half—inchrefractoroftheobservatory。Inasmuchastheseobservationsarenotonlyofhighintrinsicinterest,butareinconflict,tosomeextent,withpreviousrecords,asomewhatfullabstractofthemwillbeuseful:Theobjectofgeneralinterestwasthegreatredspot。
Theoutline,shape,andsizeofthisremarkableobjecthasremainedwithoutmaterialchangefromtheyear1879,whenitwasfirstobservedhere,untilthepresenttime。Accordingtoourobservations,duringthewholeofthisperiodithasshownasharpandwell—definedoutline,andatnotimehasitcoalescedorbeenjoinedtoanybeltinitsproximity,ashasbeenallegedbysomeobservers。Duringtheyear1885themiddleofthespotwasverymuchpalerincolourthanthemargins,causingittoappearasanellipticalring。Theringformhascontinueduptothepresenttime。Whiletheoutlineofthespothasremainedveryconstant,thecolourhaschangedmateriallyfromyeartoyear。Duringthepastthreeyears（1884—\'86）ithasattimesbeenveryfaint,soasbarelytobevisible。Thepersistenceofthisobjectforsomanyyearsleadsmetoinferthattheformerlyacceptedtheory,thatthephenomenaseenonthesurfaceoftheplanetareatmospheric,isnolongertenable。Thestatementsooftenmadeintext—books,thatinthecourseofafewdaysormonthsthewholeaspectoftheplanetmaybechanged,isobviouslyerroneous。Theovalwhitespotsonthesouthernhemisphereoftheplanet,ninedegreessouthoftheequator,havebeensystematicallyobservedateveryoppositionduringthepasteightyears。Theyaregenerallyfoundingroupsofthreeormore,butareratherdifficulttoobserve。Therotationperioddeducedfromthemisnearlythesameasfromthegreatredspot。
Thesespotsusuallyhaveaslowdriftinlongitudeofaboutfivesecondsdailyinthedirectionoftheplanet\'srotation,whenreferredtothegreatredspot;correspondingtoarotationperiodoftwentysecondslessthanthelatter。\'
\"Thisshows,\"continuedBearwarden,\"thataslongagoastowardsthecloseofthenineteenthcenturytheoldideathatwesawnothingbutthecloudsinJupiter\'satmospherewasbeginningtochange;andalsohowcloselythetwoEnglishwritersandProf。
Houghwerestudyingthesubject,thoughtheirviewsdidnotentirelyagree。Awhitespotismerelyastorm—centrepassingroundandroundtheplanet,thewindrunningalittleaheadofthesurface,whichaccountsforitsrapidrotationcomparedwiththeredspot,whichisafixture。Acriticmaysaywehavenosuchwindsonearth;towhichIreply,thatwindsonaplanetofJupiter\'ssize,withitsrateofrotation——thoughitis480,000,000milesfromthesunandtheinternalheatissonearthesurface——andwithlandandwaterarrangedastheyare,mayandindeedmustbeverydifferentfromthoseprevailingonearth,theconditionsproducingandaffectingthembeingsochanged。
Thoughthestorm—centremovestwohundredandsixtymilesanhour,thewindneednotblowatthatrate。\"
Latertheysawseveralsmallerspotsdriftingeastward,butconcludedthatanyseaworthyshipmightpasssafelythroughthem,for,thoughtheywerehurricanesofgreatviolence,thewavesweresmall。
\"Therewouldbelessdanger,\"saidBearwarden,\"ofshippingseasherethanthereisonearth;theprincipalrisktotravellerswouldbethatofbeingblownfromthedeck。Onaccountoftheair\'sweightinconnectionwithitsvelocity,thiswouldnecessitatesomeprecaution。\"
Thenextobjectofinterestwasthegreatredspot。Itproved,asCortlandthadpredicted,tobeacontinent,withatthattimenospecialcolour,thoughtheyeasilyrecognizeditbycomparingitsoutlineswiththoseofthespotinthemap。Itslength,astheyalreadyknew,wastwenty—seventhousandmiles,anditsbreadthabouteightthousandmiles,sothatitcontainedmoresquaremilesthantheentiresurfaceoftheearth,landandwaterincluded。
\"Itisclear,\"saidCortlandt,\"thatatsomeseasonofJupiter\'slongyearachangetakesplacethataffectsthecolouroftheleaves——somedroughtorprolongednorther;foritisobviousthatthatisthesimplestexplanation。Inlikemannerwemayexpectthatatsometimesmorewhitespotswillmoveacrosstheoceanthanatothers。\"
\"Onaccountofthesizeofthesecontinentsandoceans,\"saidBearwarden,\"itiseasytobelievethatmanyclimaticconditionsmayprevailherethatcanscarcelyexistonearth。Butwhatamagnificentworldtodevelop,withitsgreatrivers,lakes,andmountainsshowingateventhisdistance,andwhatnaturalresourcesmustbelyingtheredormant,awaitingourcall！Thisconstantlyrecurstomymind。Thesubjugationandthoroughopeningupofthisredspotcontinentwillprobablysupplymoreinterestingproblemsthanstraighteningtheaxisoftheearth。\"
\"Atournextvisit,\"repliedAyrault,\"whenwehaveestablishedregularinterplanetarylinesoftravel,wemayhaveanopportunitytoexamineitmoreclosely。\"Thentheyagainattractedthenearestmoonbeyondwhichtheyhadswung,increasedtherepulsiononJupiter,andsoaredawaytowardsSaturn。
\"WehaveastrikingillustrationofJupiter\'senormousmass,\"
saidCortlandt,astheapparentdiameterofthemightyplanetrapidlydecreased,\"inthefactthatnotwithstandingitsnumerousmoons,itstillrotatessorapidly。Weknowthattheearth\'sdayswereformerlybuthalforaquarteraslongasnow,havinglastedbutsixoreighthours。Theexplanationoftheelongationissimple:theearthrotatesinabouttwenty—fourhours,whilethemoonencirclesitbutonceinnearlytwenty—eightdays,sothatoursatelliteiscontinuallydrawingtheoceansbackwardagainstitsmotion。Thesetidalbrakesactingthroughthefrictionofthewateronthebottom,itsunequalpressure,andtheimpactofthewavesontheshore,arecontinuallyretardingitsrotation,sothatthedayisafractionofasecondlongernowthanitwasinthetimeofCaesar。ThissameactionisofcoursetakingplaceinJupiterandthegreatplanets,inthiscasetherebeingfivemoonsatwork。Ourmoon,weknow,rotatesonitsaxisbutoncewhileitrevolvesabouttheearth,thisbeingnodoubtduetoitsowncomparativesmallnessandthegreatattractionoftheearth,whichmusthaveproducedtremendoustidesbeforethelunaroceansdisappearedfromitssurface。\"
Incrossingtheorbitsofthesatellites,theypassednearGanymede,Jupiter\'slargestmoon。
\"This,\"saidCortlandt,\"wasdiscoveredbyGalileoin1610。Itisthreethousandfourhundredandeightymilesindiameter,whileourmoonisbuttwothousandonehundredandsixty,revolvesatadistanceofsixhundredandseventy—eightthousandthreehundredmilesfromJupiter,completesitsrevolutioninsevendaysandfourhours,andhasaspecificgravityof1。87。\"
Inpassing,theyobservedthatGanymedepossessedanatmosphere,andcontinentsandoceansoflargearea。
\"Here,\"saidBearwarden,\"wehaveabodywithadiameteraboutfivehundredmilesgreaterthantheplanetMercury。Itssize,lightspecificgravity,atmosphere,andoceansseemtoindicatethatitislessadvancedthanthatplanet,yetyouthinkJupiterhashadalongerseparateexistencethantheplanetsnearerthesun？\"
\"Undoubtedly,\"saidCortlandt。\"Jupiterwascondensedwhileinthesolar—systemnebula,andbeganitsindividualexistenceanditsevolutionarycareerlongbeforeMercurywasformed。ThematternowinGanymede,however,doubtlessremainedpartoftheJupiter—systemnebulatillafterMercury\'screation,and,beingpartofsogreatamass,didnotcoolveryrapidly。IshouldsaythatthissatellitehasaboutthesamerelationtoJupiterthatJupiterhastothesun,andisthereforeyoungerinpointoftimeaswellasofdevelopmentthanthemostdistantCallisto,andolder,atalleventsinyears,thanEuropaandIo,bothofwhicharenearer。ThissuppositioniscorroboratedbythefactthatEuropa,thesmallestofthesefour,isalsothedensest,havingaspecificgravityof2。14,itssmallnesshavingenabledittoovertakeGanymedeindevelopment,notwithstandingthelatter\'sstart。Inthefaceoftheevidencebeforeuswemustbelievethis,orelsethat,perhaps,asinthecaseoftheasteroidHilda,somethinglikeacollisionhasrejuvenatedit。Thismightaccountforitssize,andfortheNauticalAlmanac\'sstatementthatthereisa\'smallandvariable\'inclinationtoitsorbit,whileIoandEuroparevolveexactlyintheplaneofJupiter\'sequator。\"
TheyhadaboutaslongajourneybeforethemastheyhadalreadymadeingoingfromtheearthtoJupiter。Thegreatplanetsoonappearedasahugecrescent,sinceitwasbetweenthemandthesun;itsmoonsbecameasfifth—andsixth—magnitudestars,andintheeveningofthenextdayJupiter\'sdiskbecameinvisibletotheunaidedeye。Sincetherewerenowaystations,intheshapeofplanetsorasteroids,betweenJupiterandSaturn,theykeptthemaximumrepulsiononJupiteraslongaspossible,andmovedattremendousspeed。SaturnwassomewhatinadvanceofJupiterinitsorbit,sothattheircoursefromtheearthhadbeenalongtwosidesofatrianglewithanobtuseanglebetween。Duringthenextfourterrestrialdaystheysightedseveralsmallcomets,butspentmostoftheirtimewritingouttheirJovianexperiences。
DuringthesixthdaySaturn\'srings,althoughnotasmuchtiltedastheywouldbelaterintheplanet\'sseason,presentedamostsuperbsight,whiletheyspuninthesun\'srays。Soonafterthistheeightmoonsbecamevisible,and,whileslightlyreducingtheCallisto\'sspeed,theycrossedtheorbitsofIapetus,Hyperion,andTitan,whentheyknewtheywerebutsevenhundredandfiftythousandmilesfromSaturn。
\"Iamanxioustoascertain,\"saidCortlandt,\"whetherthecompositionofyonderringsissimilartothatofthecometthroughwhichwepassed。Iamsuretheyshinewithmorethanreflectedlight。\"
\"Wehavebeeninthehabit,\"saidAyrault,\"ofassociatingheatwithlight,butitisobviousthereissomethingfarmoresubtleaboutcometarylightandthatofSaturn\'srings,bothofwhichseemtohavetheirbirthintheintensecoldofinterplanetaryspace。\"
PassingclosetoMimas,Saturn\'snearestmoon,theysupplementeditsattraction,afterswingingby,bytheirownstrongpull,bringingtheirspeeddowntodeadslowastheyenteredtheoutsidering。Atdistancesoftenofhalfamiletheyfoundmeteoricmasses,sometimeslumpsthesizeofahouse,oftennolargerthanapples,whilesmallparticleslikegrainsofsandmovedbetweenthem。Thereweretwomotions。TheringrevolvedaboutSaturn,andtheparticlesvibratedamongthemselves,evidentlykeptapartbyamutualrepulsion,whichseemedbothtoincreaseanddecreasefasterthangravitation;foronapproachingoneanothertheyweremorestronglyrepelledthanattracted,butwhentheyseparatedtherepulsiondecreasedfasterthantheattraction,sothatafteratimedivergenceceased,andtheyremainedatfixeddistances。
TheCallistosoonbecameimbuedwithmotionalso,butnothingeverstruckit。Whenanylargemasscameunusuallynear,bothitandtheircaremittedlight,andtheyrapidlyseparated。Thesunlightwasnotasstronghereasithadbeenwhentheyenteredthecomet,andastheypenetratedfarthertheywerebetterabletoobservetheomnipresentluminosity。Theyweresomewhatpuzzledbytheapproachofcertainlight—centres,whichseemedtocontainnothingbutthisconcentratedbrightness。Occasionallyoneofthesecentreswouldglowverybrightlynearthem,andsimultaneouslyrecede。AtsuchtimestheCallistoalsoglowed,anditselfrecoiledslightly。Atfirstthetravellerscouldnotaccountforthis,butfinallytheyconcludedthatthecentresmustbemeteoricmassesconsistingentirelyofgases,possessingweightthoughinvisible。
\"Wehaveagaintoface,\"saidCortlandt,\"thatsingularlawthattillrecentlywedidnotsupposeexistedonearth。Allkindsofsuppositionshavebeenadvancedinexplanationoftheserings。
Somewritershavetheirthickness,lookedatfromthethinedge,asfourhundredmiles,someonehundred,andsomebutforty。Oneastronomerofthenineteenthcentury,amanofconsiderableeminence,wasconvincedthattheyconsistedofsheetsofliquid。
Now,itshouldbeobviousthatnoliquidcouldmaintainitselfhereforaminute,foritwouldeitherfallupontheplanetasacrushinghail,or,ifdependentforitsshapeonitsowntenacity,itwouldbreakifformedofthetougheststeel,onaccountofthetremendousweight。Anynumberoftheorieshavebeenadvancedbyanynumberofmen,butinweightwehavetherub。NoonehasevershownhowtheseinnumerablefragmentsmaintainthemselvesataheightofbutafewthousandmilesaboveSaturn,withstandingthegiant\'sgravitation—pull。Theirrateofrevolution,thoughrapid,doesnotseemfastenoughtosustainthem。NeitherhaveIeverseenitexplainedwhythesmallfragmentsdonotfalluponthelargeones,thoughmanyastronomershavepicturedthecompositionoftheseringsaswefindtheyexist。Nordoweknowwhythemoleculesofagasaredrivenfartherapartbyheat,whiletheiractivityisalsoincreased,thoughifthisactivitywererevolutionaboutoneanothertodevelopthecentrifugal,itwouldnotneedtobeasstrongthenaswhentheyarecoldandnearertogether。Theremaybeexplanations,butIhavefoundnoneinanyoftheliteratureI
haveread。Itseemstomethatallthisleadstobutoneconclusion,viz。:apergyistheconstantandvisiblecompanionofgravitation,onthesegreatplanetsJupiterandSaturn,perhapsonaccountofsomepeculiarinfluencetheypossess,andalsoincomets,inthecaseoflargemasses,whileonearthitappearsnaturallyonlyamongmolecules——thoseofgasesandeveryothersubstance。\"
\"Ishouldgoastepfurther,\"saidBearwarden,\"andsayourearthhasthepeculiarity,sinceitdoesnotpossesstheinfluencenecessarytogeneratenaturallyagreatorevenconsiderabledevelopmentofapergy。Theelectricityofthunderstorms,northernlights,andotherforcesseemstobeproducedfreely,butasregardsapergyourplanet\'snaturalproductivenessappearstobesmall。\"
Theomnipresentluminositycontinued,buttheglowwasscarcelybrightenoughtobeperceivedfromtheearth。
\"Ibelieve,however,\"saidBearwarden,referringtothis,\"thatwheneverasatellitepassesnearthesefragments,preferablywhenitenterstheplanet\'sshadow,sincethatwillremoveitsownlight,itwillcreatesuchactivityamongthemastomaketheluminosityvisibletothelargetelescopesorgelatineplatesonearth。\"
\"Now,\"saidAyrault,\"thatwehaveevolvedenoughtheoriestokeepastronomersbusyforsometime,iftheyattempttodiscussthem,Isuggestthatwealightandleavetheabstractfortheconcrete。\"
Whereupontheypassedthroughtheinnerringandrapidlysanktotheground。
BOOKIII。
CHAPTERI。
SATURN。
Landingonaplaceabouttendegreesnorthoftheequator,sothattheymightobtainagoodviewofthegreatrings——sinceON
thelineonlythethinedgewouldbevisible——theyopenedaport—holewiththesamecautiontheyhadexercisedonJupiter。
Againtherewasarushofair,showingthatthepressurewithoutwasgreaterthanthatwithin;butonthisoccasionthebarometerstoppedatthirty—eight,fromwhichtheycalculatedthatthepressurewasnineteenpoundstothesquareinchontheirbodies,insteadoffifteenasatsea—levelonearth。Thisdifferencewassoslightthattheyscarcelyfeltit。TheyalsodiscardedtheapergeticoutfitsthathadbeensousefulonJupiter,asunnecessaryhere。Theairwasanicyblast,andthoughtheyquicklyclosedtheopening,theinterioroftheCallistowasconsiderablychilled。
\"Weshallwantourwinterclothes,\"saidBearwarden;\"itmightbemorecomfortableforusexactlyontheequator,thoughthesceneatnightwillbefarfinerhere,ifwecanstandtheclimate。
Doubtlessitwillalsobewarmersoon,forthesunhasbutjustrisen。\"
\"Isuspectthisismerelyoneofthecoldwavesthatrushtowardstheequatoratthisseason,whichcorrespondstoaboutthe10thofourSeptember,\"repliedCortlandt。\"ThepolesofSaturnmustbeintenselycoldduringitslongwinteroffourteenandthreequarteryears,for,theaxisbeinginclinedtwenty—sevendegreesfromtheperpendicularofitsorbit,thepoleturnedfromthesunismoreshutofffromitsheatthanours,andinadditiontothisthemeandistance——morethaneighthundredandeightymillionmiles——isverygreat。Sincethechemicalcompositionoftheairwehaveinhaledhasnottroubledourlungs,itisfairtosupposeweshallhavenodifficultyinbreathing。\"
Havingdressedthemselvesmorewarmly,andseenbyathermometertheyhadplacedoutsidethatthetemperaturewasthirty—eightdegreesFahrenheit,whichhadseemedverycoldcomparedwiththewarmthinsidetheCallisto,theyagainopenedtheport—hole,thistimeleavingitopenlonger。Whattheyhadfeltbeforewasevidentlymerelyasuddengust,fortheairwasnowcomparativelycalm。
Findingthatthedoctor\'spredictionastothesuitabilityoftheairtotheirlungswascorrect,theyventuredout,closingthedoorastheywent。
Expecting,asonJupiter,tofindprincipallyvertebratesofthereptileandbirdorder,theycarriedgunsandcartridgesloadedwithbuckshotandNo。1,trustingforsolid—ballprojectilestotheirrevolvers,whichtheyshovedintotheirbelts。Theyalsotooktest—tubesforexperimentsontheSaturnianbacilli。
Hangingabucketunderthepipeleadingfromtheroof,tocatchanyrainthatmightfall——fortheyrememberedthescarcityofdrinking—wateronJupiter——theysetoutinasouthwesterlydirection。
Walkingalong,theynoticedonallsidestallliliesimmaculatelypureintheirwhiteness,andmushroomsandtoadstoolsnearlyafoothigh,theformerhavingadeliciousflavourandextremefreshness,asthoughonlyanhourold。Theyhadseennoanimallife,orevensignofit,andwerewonderingatitsdearth,whensuddenlytwolargewhitebirdsrosedirectlyinfrontofthem。
Likethought,BearwardenandAyraulthadtheirgunsup,snappingthethumb—piecesover\"safe\"andpullingthetriggersalmostsimultaneously。Bearwarden,havingdoublebuckshot,killedhisbirdatthefirstfire;butAyrault,havingonlyNo。1,hadtogivehisthesecondbarrel,almostalldamageinbothcasesbeinginthehead。Oncomingclosetotheirvictimstheyfoundthemtomeasuretwelvefeetfromtiptotip,andtohaveatremendousthicknessoffeathersanddown。
\"Fromthelooksofthesebeauties,\"saidBearwarden,\"Ishouldsaytheyprobablyinhabitedaprettycoldplace。\"
\"Theyaredoubtlessnorthernbirds,\"saidCortlandt,\"thathavejustcomesouth。Itiseasytobelievethatthedepthtowhichthetemperaturemayfallintheupperairofthisplanetmustbesomethingstartling。\"
Astheyturnedfromthecranes,towhichspeciesthebirdsseemedtobelong,theybecamemutewithastonishment。Everymushroomhaddisappeared,butthetoadstoolsstillremained。
\"Isitpossiblewedidnotseethem？\"gaspedAyrault。
\"Wemustinadvertentlyhavewalkedsomedistancesincewesawthem,\"saidCortlandt。
\"TheywerewhatIlookedforwardtoforlunch,\"exclaimedBearwarden。
Theyweregreatlyperplexed。Themushroomswereallaboutthemwhentheyshotthebirds,whichstilllaywheretheyhadfallen。
\"Wemustbeveryabsent—minded,\"saidthedoctor,\"orperchanceourbrainsareaffectedbytheair。Wemustanalyzeittoseeifitcontainsourownproportionofoxygenandnitrogen。Therewasagooddealofcarbonic—acidgasonJupiter,butthatwouldhardlyconfuseoursenses。Thestrangethingis,thatweallseemtohavebeenimpressedthesameway。\"
Concludingthattheymusthavebeenmistaken,theycontinuedontheirjourney。
Allabouttheyheardacurioushumming,asthatofbees,orlikethemurmuringofprayersinaresonantcathedral。Thinkingitwasthewindinthegreattreesthatgrewsinglyaroundthem,theypaidnoattentiontoituntil,emergingonanopenplainandfindingthatthesoundcontinued,theystopped。
\"Now,\"saidBearwarden,\"thisismorecuriousthananythingwefoundonJupiter。Herewehaveanincessantandratherpleasantsound,withnovisiblecause。\"
\"Itmaypossiblybesomepeculiarityofthegrass,\"repliedCortlandt,\"though,shoulditcontinuewhenwereachsandyorbaresoil,Ishallbelieveweneedadoseofquinine。\"
\"IFEELperfectlywell,\"saidAyrault;\"howisitwithyou？\"
Eachfindingthathewasinanormalstate,theyproceeded,determined,ifpossible,todiscoverthesourcefromwhichthesoundscame。SuddenlyBearwardenraisedhisguntobringdownalong—beakedhawk;butthebirdflewoff,andhedidnotshoot。
\"Plaguetheluck！\"saidhe;\"IwentblindjustasIwasabouttopull。Ahazeseemedtocoverbothbarrels,andcompletelyscreenedthebird。\"
\"TheCallistowillsoonbehiddenbythosetrees,\"saidCortlandt。\"Ithinkwehadbettertakeourbearings,for,ifourcrackshotisgoingtomisslikethat,wemaywantcannedprovisions。\"
Accordingly,hegotouthissextant,tookthealtitudeofthesun,gotcross—bearingsandafewangles,andbegantomakearoughcalculation。Forseveralminutesheworkedindustriously,usedtherubberattheendofhispencil,triedagain,andthenscratchedout。\"ThathummingconfusesmesothatIcannotworkcorrectly,\"saidhe,\"whilethemostirrelevantthingsentermymindinspiteofme,andmixupmyfigures。\"
