第17章

类别:其他 作者:Rev. J. M. Bacon字数:12243更新时间:18/12/18 14:00:38
andforalengthoftimesuchsoundswerevouchsafedus——thebarkofadog,thelowingofcattle,theringingtrotofahorseonsomehardroadfardown。 Andthen,aswewereexpecting,thesunclimbedupintoanunsulliedsky,and,mountingbyleapsandbounds,wewatchedthecloudfloorrecedingbeneathus。Theeffectwasextremelybeautiful。AdescriptionwrittentotheTimesthenextmorning,whiletheimpressionwasstillfresh,andfromnotesmadeatthisperiod,ranthus:——\"Awaytoaninfinitelydistanthorizonstretchedrollingbillowsofsnowywhiteness,brokenuphereandthereintoseemingicefields,withhugefantastichummocks。Elsewheredomesandspiresrearedthemselvesabovethegeneralsurface,oranisolatedMatterhorntoweredintospace。Insomequartersitwasimpossibletolookwithouttheconvictionthatweactuallybeheldtheoutlineofloftycliffsoverhanginganonetoodistantsea。\"Shortlywebegantohearloudreportsoverhead,resemblingsmallexplosions,andweknewwhatthesewere——themoist,shrunkennettingwasgivingoutunderthehotsunandyieldingnowandagainwithsuddenreleasetotherapidlyexpandinggas。Itwas,therefore,withgraveconcern,butwithnosurprise,thatwhenwenextturnedtotheaneroidwefoundtheindexpointingto9,000feet,andstillmovingupwards。 Hourafterhourpassedby,and,soundshavingceasedtoreachus,itremainsuncertainwhetherornowewereactuallycarriedouttoseaandheadedbackagainbycontrarycurrents,anexperiencewithwhichaeronauts,includingthewriter,havebeenfamiliar;but,atlength,therewasborneuptousthedistantsoundofheavyhammersandoffrequenttrains,fromwhichwegatheredthatwewereprobablyoverBristol,anditwasthenthatthethoughtoccurredtomydaughterthatwemightpossiblycommunicatewiththosebelowwithaviewtosuccour。 Thisledtoourwritingthefollowingmessagemanytimesoveronblanktelegraphformsandcastingthemdown:——\"Urgent。 LargeballoonfromNewburytravellingoverheadabovetheclouds。Cannotdescend。Telegraphtoseacoast(coast—guards) tobereadytorescue。——BaconandSpencer。\" Whilethusoccupiedwecaughtthesoundofwaves,andtheshriekofaship’ssiren。WewerecrossingareachoftheSevern,andmostofourmissivesprobablyfellinthesea。Butovertheestuarytheremusthavebeenacolduppercurrentblowing,whichcrippledourballoon,fortheaneroidpresentlytoldofafallof2,000feet。Itwasnowpastnoon,andtoustheturnofthetidewascome。Veryslowly,andwithstrangefluctuations,theballooncreptdowntillitreachedandbecameenvelopedinthecloudbelow,andthentheendwasnear。Theactualdescentoccupiednearlytwohours,andaffordsacuriousstudyinaerostation。Thedetailsoftheballoon’sdyingstrugglesandofourownroughdescent,entailingthefractureofmydaughter’sarm,aretoldinanothervolume。* WefellnearNeath,Glamorganshire,onlyoneandahalfmilesshortofthesea,completingavoyagewhichisarecordinEnglishballooning——tenhoursfromstarttofinish。 *\"ByLandandSky,\"bytheAuthor。 CHAPTERXXVI。RECENTAERONAUTICALEVENTS。 ThefirsttrialoftheZeppelinairshipwasarrangedtotakeplaceonJune30th,1900,adaywhich,fromabsenceofwind,waseminentlywellsuitedforthepurpose;buttheinflationprovedtooslowaprocess,andoperationswerepostponedtothemorrow。Themorrow,however,wassomewhatwindy,causingdelay,andbythetimeallwasinreadinessdarknesshadsetinandthestartwasoncemorepostponed。Ontheeveningofthethirddaythemonstercraftwasskilfullyandsuccessfullymanoeuvred,and,risingwithaverylightwind,gotfairlyaway,carryingCountZeppelinandfourotherpersonsinthetwocars。Driftingwiththewind,itattainedaheightofsome800 or900feet,atwhichpointthesteeringapparatusbeingbroughtintoplayitcircledroundandfacedthewind,whenitremainedstationary。Butnotforlong。Shortlyitbegantodescendand,sinkinggradually,gracefully,andinperfectsafety,inaboutnineminutesitreachedandrestedonthewater,whenitwastowedhome。 Alittlelaterinthemonth,July,anothertrialwasmade,whenawindwasblowingestimatedatsixteenmilesanhour。Asonthepreviousoccasion,thedirectinfluenceofthesunwasavoidedbywaitingtilleveninghours。Itascendedat8p。m。,andtheenginesgettingtoworkitmadeaslowprogressofabouttwomilesanhouragainstthewindforabout31/2miles,whenoneoftheruddersgaveway,andthemachinewasobligedtodescend。 OntheeveningofOctober24thofthesameyear,inverycalmweatherandwithbetterhope,anotherascentwasmade。Onthisoccasion,however,successwasfrustratedbyoneoftherearruddersgettingfoulofthegear,followedbytheescapeofgasfromoneoftheballoons。 Anotherandmoresuccessfultrialtookplaceinthesamemonth,againincalmatmosphere。Inferiorgaswasemployed,anditwouldappearthatthevesselhadnotsufficientbuoyancy。Itremainedaloftforaperiodoftwentyminutes,duringwhichitprovedperfectlymanageable,makingagracefuljourneyoutandhome,andreturningclosetoitspointofdeparture。Thismagnificentairship,theresultoftwentyyearsofexperiment,hassincebeenabandonedandbrokenup;yetthesacrificehasnotbeenwithoutresult。OverandabovethestimuluswhichCountZeppelin’sgreatendeavourhasgiventotheaeronauticalworld,twospecialtriumphsarehis。Hehasshownballoonistshowtomakeaperfectlygas—tightmaterial,andhasraisedpowerfulpetroleummotorsinaballoonwithsafety。 Intheearlypartof1900itwasannouncedthatamemberoftheParisAeroClub,whoatthetimewithheldhisname(M。Deutsch) offeredaprizeof100,000francstotheaeronautwho,eitherinaballoonorflyingmachine,startingfromthegroundsoftheAeroClubatLongchamps,wouldmakeajourneyroundtheEiffelTower,returningtothestartingplacewithinhalfanhour。Thedonorwouldwithdrawhisprizeifnotwonwithinfiveyears,andinthemeanwhilewouldpay4,000francsannuallytowardstheencouragementofworthyexperimenters。 Itwasfromthistimethatflyingmachinesingreatvarietyandgoodlynumberbegantobeheardof,ifnotactuallyseen。OneoftheearliesttobeannouncedinthePresswasamachineinventedbytheRussian,Feedoroff,andtheFrenchman,Dupont。 Dr。Danilewskycameforwardwithaflyingmachinecombiningballoonandaeroplane,thesteeringofwhichwouldbeworkedlikeavelocipedebythefeetoftheaeronaut。 Mr。P。Y。Alexander,ofBath,whohadlongbeenanenthusiasticballoonist,andwhohaddevotedavastamountofpains,originality,andengineeringskilltothepursuitofaeronautics,wasatthistimegivingmuchattentiontotheflyingmachine,andwas,indeed,oneoftheassistantsinthefirstsuccessfullaunchingoftheZeppelinairship。InconcertwithMr。W。G。Walker,A。M。I。C。E。,Mr。Alexandercarriedoutsomevaluableandexhaustiveexperimentsontheliftingpowerofairpropellers,30feetindiameter,drivenbyaportableengine。Theresults,whichwereofapurelytechnicalnature,havebeenembodiedinacarefullycompiledmemoir。 Anairshipnowappeared,inventedbyM。Rose,consistingoftwoelongatedvesselsfilledwithgas,andcarryingtheworkinggearandcarbetweenthem。Themachinewasintentionallymadeheavierthanair,andwasoperatedbyapetrolmotorof12—horsepower。 Itwasnowthatannouncementsbegantobemadetotheeffectthat,nexttotheZeppelinairship,M。SantosDumont’sballoonwasprobablyattractingmostoftheattentionofexperts。Theaccountgivenofthisairvessel]bytheDailyExpresswassomewhatstartling。Theballoonproperwascomparedtoalargetorpedo。Threefeetbeneaththishangsthegasolinemotorwhichistosupplythepower。Thepropelleris12feetindiameter,andisrevolvedsorapidlybythemotorthattheenginefrequentlygetsredhot。Theonlyaccommodationforthetravellerisalittlebicycleseat,fromwhichtheaeronautwilldirecthismotorandsteeringgearbymeansoftreadles。 Thentheinclinationordeclinationofhismachinemustbenotedonthespiritlevelathisside,andthe200oddpoundsofballastmustberegulatedasthecourserequires。 AmoredetailedaccountofthisnavigableballoonwasfurnishedbyamemberoftheParisAeroClub。Fromthisauthoritywelearnthatthecapacityoftheballoonwas10,700cubicfeet。 Itcontainedaninnerballoonandanairfan,thefunctionofwhichwastomaintaintheshapeoftheballoonwhenmeetingthewind,andthewholewasoperatedbya10—horsepowermotorcapableofworkingthescrewat100revolutionsperminute。 ButbeforetheaerialexploitsofSantosDumonthadbecomefamous,balloonshadagainclaimedpublicattention。OnAugust1stCaptainSpelterini,withtwocompanions,takingaballoonand180cylindersofhydrogentothetopoftheRigiandascendingthence,pursuedanorth—eastcourse,acrossextensiveandbeautifultractsoficefieldandmountainfastnessesunvisitedbymen。Thedescent,whichwasdifficultandcritical,washappilymanoeuvred。ThistookplaceontheGnuetseven,apeakover5,000feethigh,theplateauonwhichthevoyagerslandedbeingdescribedasonly50yardssquare,surroundedbyprecipices。 Onthe10thofSeptemberfollowingthewriterwasfortunateincarryingoutsomewirelesstelegraphyexperimentsinaballoon,thesuccessofwhichisentirelyduetotheunrivalledskillofMr。NevilMaskelyne,F。R。A。S。,andtohiscleveradaptationofthespecialapparatusofhisowninventiontotheexigenciesofafreeballoon。TheoccasionwasthegardenpartyattheBradfordmeetingoftheBritishAssociation,AdmiralSirEdmundFremantletakingpartinthevoyage,withMr。PercivalSpencerincharge。Theexperimentwastoincludethefiringofamineinthegroundstwominutesaftertheballoonhadleft,andthisitemwasentirelysuccessful。Themainideawastoattempttoestablishcommunicationbetweenabaseandafreeballoonretreatingthroughspaceataheightbeyondpracticablegunshot。Thewindwasfastandsqually,andtheunavoidableroughjoltingwhichthecarreceivedatthestartputthetransmittinginstrumentoutofaction。Themessages,however,whichweresentfromthegroundsatListerParkwerereceivedandwatchedbytheoccupantsofthecaruptoadistanceoftwentymiles,atwhichpointthevoyageterminated。 OnSeptember30th,andalsoonOctober9th,ofthisyear,tookplacetwoprincipalballoonracesfromVincennesinconnectionwiththeParisExposition。Inthefirstrace,amongthosewhocompetedwereM。JacquesFaure,theCountdelaVaulx,andM。 JacquesBalsan。TheCountwasthewinner,reachingWocawek,inRussianPoland,atravelof706miles,in21hours34minutes。 M。Balsanwassecond,descendingnearDantziginEastPrussia,757miles,in22hours。M。JacquesFaurereachedMamlitz,inEastPrussia,adistanceof753miles。 InthefinalracetheCountdelaVaulxmadearecordvoyageof1,193miles,reachingKorosticheff,inRussia,in35hours45 minutes,attainingamaximumaltitudeof18,810feet。M。J。 Balsanreachedagreaterheight,namely,21,582feet,travellingtoRodom,inRussia,adistanceof843miles,in27 hours25minutes。 Somephenomenalaltitudeswereattainedatthistime。InSeptember,1898,Dr。Berson,ofBerlin,ascendedfromtheCrystalPalaceinaballooninflatedwithhydrogen,underthemanagementofMr。StanleySpencer,oxygenbeinganessentialpartoftheequipment。Thestartwasmadeat5p。m。,andtheballoonatfirstdriftedsouth—east,outoverthemouthoftheThames,untilatanaltitudeof10,000feetanuppercurrentchangedthecoursetosouthwest,theballoonmountingrapidlytill23,000feetwasreached,atwhichheightthecoastofFrancewasplainlyseen。At25,000feetbothvoyagersweregasping,andcompelledtoinhaleoxygen。At27,500feet,onlyfourbagsofballastbeingleft,thedescentwascommenced,andasafelandingwaseffectedatRomford。 SubsequentlyDr。Berson,incompanywithDr。Suring,ascendingfromBerlin,attainedanaltitudeof34,000feet。At30,000 feettheaeronautswereinhalingoxygen,andbeforereachingtheirhighestpointbothhadforaconsiderabletimeremainedunconscious。 In1901anewaeroplaneflyingmachinebegantoattractattention,theinventionofHerrKress。AnovelfeatureofthemachinewasadevicetorenderitofavailforArctictravel。 Inshapeitmightbecomparedtoaniceboatwithtwokeelsandalongstem,thekeelsbeingadaptedtorunoniceorsnow,whiletheboatwouldfloatonwater。Powerwastobederivedfromapetrolmotor。 AtthesameperiodM。HenrySutorwasbusyonLakeConstancewithanairshipdesignedalsotofloatonwater。ThenMr。 Buchananfollowedwithafish—shapedvessel,oneofthemostimportantspecialitiesofwhichconsistedinsidepropellers,thesurfacesofwhichwereroughenedwithminutediagonalgroovestoeffectagreatergripontheair。 Nolessoriginalwastheairship,100feetlong,andcarrying18,000cubicfeetofgas,whichMr。W。Beedlewasengagedupon。 Inthismachine,besidesthepropellersforcontrollingthehorizontalmotion,therewasonetoregulateverticalmotion,withaviewofobviatingexpenditureofgasorballast。 ButbythistimeM。SantosDumont,pursuinghishobbywithunparalleledperseverance,hadbuiltinsuccessionnolessthansixairships,meetingwithnomeansuccess,profitingbyeverylessontaughtbyfailures,andmakinglightofallaccidents,greatorsmall。OnJuly15th,1901,hemadeafamoustryfortheDeutschprizeinacigar—shapedballoon,110feetlong,19,000cubicfeetcapacity,carryingaDaimleroilmotorof15—horsepower。Thedaywasnotfavourable,but,startingfromtheParcd’Aerostation,hewasabreastoftheEiffelTowerinthirteenminutes,circlingroundwhich,andbattlingagainstaheadwind,hereachedthegroundsoftheAeroClubin41 minutesfromthestart,or11minuteslatebytheconditionsoftheprize。Acylinderhadbrokendown,andthebalanceofthevesselhadbecomeupset。 Withinafortnight——July29th——infavourableweather,hemadeanotherflight,lastingfifteenminutes,attheendofwhichhehadreturnedtohisstartingground。ThenonAugust8thamoremomentousattemptcameoff。Sailingupwitharapidascent,andflyingwiththewind,SantosDumontcoveredthedistancetotheTowerinfiveminutesonly,andgracefullyswunground; but,immediatelyafter,thewindplayedhavoc,slowingdownthemotor,atthesametimedamagingtheballoon,andcausinganescapeofgas。OnthisSantosDumont,ascendinghigherintothesky,quittedthecar,andclimbedalongthekeeltoinspect,and,ifpossible,rectifythemotor,butwithlittlesuccess。Theballoonwasemptying,andthemachinepitchedbadly,tillafurtherrentoccurred,whenitcommencedfallinghopelesslyandwithaspeedmomentarilyincreasing。 Slantingoveraroof,theballooncaughtachimneyandtoreasunder;butthewreck,alsocatching,heldfast,whilethecarhunghelplesslydownablankwall。Inthisperilouspredicamentgreatcoolnessandagilityaloneaverteddisaster,tillfiremenwereabletocometotherescue。 Theairshipwasdamagedbeyondrepair,butbySeptember6thanotherwascompleted,andontrialappearedtoworkwelluntil,whiletravellingatspeed,itwasbroughtupandbadlystrainedbythetrailropecatchingintrees。 EarlyinthenextmonththeyoungBrazilianwasaloftagain,withweatherconditionsentirelyinhisfavour;butagaincertainminormishapspreventedhisnextstrugglefortheprize,whichdidnottakeplacetillthe19th。Onthisdayalightcrosswindwasblowing,notsufficient,however,seriouslytoinfluencethefirststageofthetimerace,andtheoutwardjourneywasaccomplishedwithadirectflightinnineminutes。Onroundingthetower,however,thewindbegantotellprejudicially,andthepropellerbecamederanged。Onthis,lettinghisvesselfallofffromthewind,SantosDumontcrawledalongtheframeworktillhereachedthemotor,whichhesucceededinagainsettinginworkingorder,thoughnotwithoutadelayofseveralminutesandsomelossofground。Fromthatpointthereturnjourneywasaccomplishedineightminutes,andtheracewas,atthetime,declaredlostby40secondsonly。 ThemostimportantandnovelfeatureintheairshipsconstructedbySantosDumontwastheinternalballonet,inflatedautomaticallybyaventilator,theexpedientbeingdesignedtopreservetheshapeofthemainballoonitselfwhilemeetingthewind。Onthewhole,itansweredwell,andtooktheplaceoftheheavywirecageusedbyZeppelin。 M。deFonvielle,commentingontheachievementsofSantosDumont,wrote:——\"Itdoesnotappearthathehasnavigatedhisballoonagainstmorethanverylightwinds,butinhismachineryhehasshownsuchattentiontodetailthatitmayreasonablybeexpectedthatifhecontinuestoincreasehismotivepowerhewill,erelong,exceedpastperformances。\" Mr。Chanutehasafurtherwordtosayaboutthepossibilityofmakingballoonsnavigable。Heconsidersthattheirsizewillhavetobegreattothevergeofimpracticabilityandthepowerofthemotorenormousinproportiontoitsweight。Astoflyingmachines,properlysocalled,hecalculatesthebestthathasbeendonetobethesustainingoffrom27lbs。to55 lbs。perhorsepowerbyimpactupontheair。ButMr。Chanutealsoarguesthattheequilibriumisofprimeimportance,andonthispointtherecouldscarcelybeagreaterauthority。Nooneoflivingmenhasgivenmoreattentiontotheproblemof\"soaring,\"anditisstatedthathehashadaboutathousand\"slides\"madebyassistants,withdifferenttypesofmachine,andallwithouttheslightestaccident。 Manyotheraerialvesselsmightbementioned。Mr。T。H。 Bastin,ofClapham,hasbeenengagedformanyyearsonamachinewhichshouldimitatebirdflightasnearlyasthismaybepracticable。 BaronBradskyaimsatanavigableballoononanambitiousscale。M。TatinisanothercandidatefortheDeutschprize。 OfDr。Barton’sairshipmoreislookedfor,asbeingdesignedfortheWarOffice。Itisunderstoodthattheofficialrequirementsdemandamachinewhich,whilecapableoftransportingamanthroughtheairataspeedof13milesanhour,canremainfullyinflatedfor48hours。Oneofthemostsanguine,aswellasenterprising,imitatorsofSantosDumontwasafellowcountryman,AugusteSevero。Ofhismachineduringconstructionlittlecouldbegathered,andstilllessseen,fromthefactthatthevariouspartswerebeingmanufacturedatdifferentworkshops,butitwasknowntobeoflargesizeandtobefittedwithpowerfulmotors。Thiswasanill—fatedvessel。AtanearlyhouronMay12thofthisyear,1902,allPariswasstartledbyareportthatM。Severoandhisassistant,M。Sachethadbeenkilledwhilemakingatrialexcursion。Itappearsthatatdaybreakithadbeendecidedthatthefavourablemomentfortrialhadarrived。Themachinerywasgotready,andwithlittledelaytheairvesselwasdismissedandrosequietlyandsteadilyintothecalmsky。 TheDailyMailgivesthefollowingaccountofwhatensued:—— \"Forthefirstfewminutesallwentwell,andthemotorseemedtobeworkingsatisfactorily。Theairshipansweredthehelmreadily,andadmiringexclamationsrosefromthecrowd……Butasthevesselrosehighershewasseentofallofffromthewind,whiletheaeronautscouldbeseenvainlyendeavouringtokeepherheadon。ThenM。Severocommencedthrowingoutballast……Allthistimetheshipwasgraduallysoaringhigherandhigheruntil,justasitwasovertheMontparnasseCemetery,attheheightof2,000feet,asheetofflamewasseentoshootupfromoneofthemotors,andinstantlytheimmensesilkenvelopecontaining9,000cubicfeetofhydrogenwasenvelopedinleapingtonguesoffire……Assoonastheflamescameincontactwiththegasatremendousexplosionfollowed,andinaninstantallthatwasleftoftheairshipfelltotheearth。\"Bothaeronautsweredashedtopieces。Itwasthoughtthatthefatalitywascausedthroughfaultyconstruction,theescapevalveforthegasbeingsituatedonlyaboutninefeetfromthemotor。ItwasannouncedbyCountdelaVaulxthatduringthesummerof1901hewouldattempttocrosstheMediterraneanbyaballoon,provisionedforthreeweeks,maintainingcommunicationwiththecoastduringhisvoyagebywirelesstelegraphyandothermethodsofsignalling。 Hewastomakeuseofthe\"HerveDeviator,\"orsteeringapparatus,whichmaybedescribedasaseriesofcupshapedplatesdippinginthewaterattheendofatrailrope。Bymeansofcontrollingcordsworkedfromthecar,thewholeseriesofplatescouldbeturnedatanangletothedirectionofthewind,bywhichtheballoon’scoursewouldbealtered。 CountdelaVaulxattemptedthisgrandjourneyonOctober12th,startingfromToulonwiththeintentionofreachingAlgiers,takingtheprecaution,however,ofhavingacruiserinattendance。WhenfiftymilesoutfromMarseillesapassingsteamerreceivedfromtheballoonthesignal,\"All’swell\";butthewindhadveeredroundtotheeast,and,remainingpersistentlyinthisquarter,theCountabandonedhisventure,and,signallingtothecruiser,succeededinalightingonherdeck,not,however,beforehehadcompletedthesplendidandrecordvoyageof41hours’duration。 CHAPTERXXVII。THEPOSSIBILITIESOFBALLOONSINWARFARE。 Clearlythetimehasnotyetarrivedwhentheflyingmachinewillbeserviceableinwar。Yetwearenotwithoutthosetheoriserswho,atthepresentmoment,wouldseriouslyproposeschemesforconveyingdynamiteandotherexplosivesbyairship,ordroppingthemoverhostileforcesorfortresses,orevenfleetsatsea。Theygoyetfurther,andgravelydiscussthepointwhethersuchwarfarewouldbelegitimate。We,however,maysayatonce,emphatically,thatanysuchschemeissimplyimpracticable。Itmustbeabundantlyevidentthat,sofar,noformofdirigibleairshipexistswhichcouldbereliedontocarryoutanyrequiredmanoeuvreinsuchatmosphericconditionsasgenerallyprevail。If,evenincalmandfavourableweather,moreoftenthannotmotorsbreakdown,orgearcarriesaway,whathopeisthereforanyaerialcraftwhichwouldattempttobattlewithsuchwindcurrentsascommonlyblowaloft? Andwhenweturntotheballoonproper,arechancesgreatlyimproved?Theeminentlypracticalaeronaut,JohnWise,aswastoldinChapterXII。,preparedaschemeforthereductionofVeraCruzbytheagencyofaballoon。Letusglanceatit。A singleballoonwastosuffice,measuring100feetindiameter,andcapableofraisinginthegross30,000lbs。Tomanoeuvrethismonstrousenginehecalculateshewouldrequireacablefivemileslong,bymeansofwhichhehoped,insomemanner,toworkhiswaydirectlyoverthefortress,andtoremainpoisedatthatpointattheheightofamileinthesky。Oncegrantedthathecouldarriveandmaintainhimselfatthatposition,thethrowingoutofcombustibleswouldbesimple,thougheventhenthespotwheretheywouldalightafterthedropofamilewouldbebynomeanscertain。Itisalsoobviousthatavastamountofgaswouldhavetobesacrificedtocompensatefortheprodigaldischargeofballastintheformofmissiles。 Theideaofmanoeuvringaballooninawind,andpoisingitinthemannersuggested,is,ofcourse,preposterous;andwhenoneconsiderstheattempttoaimbombsfromamovingballoonhighinairthecasebecomesyetmoreabsurd。Anysuchmissilewouldpartakeofthemotionoftheballoonitself,anditwouldbeimpossibletotellwhereitwouldstriketheearth。 Togiveanexamplewhichisoftenenoughtriedinballoontravelwhenthegroundbelowisclear。Aglassbottle(presumablyempty)iscastoverboardanditsfallwatched。Itisseennottobeleftbehind,buttokeeppacewiththeballoon,shrinkinggraduallytoanobjecttoosmalltobediscerned,exceptwheneverynowandthenarayofsunlightreflectedoffitrevealsitforamomentasitcontinuestoplungedownwards。Afteraveryfewsecondstheimpressionisthatitisabouttoreachtheearth,andtheeyeformsaguessatsomespotwhichitwillstrike;butthespotisquicklypassed,andthebottletravelsfarbeyondacrossafield,overthefurtherfence,andvastlyfurtheryet;indeed,inasmuchastofallamileinairaheavybodymaytakeovertwentyseconds——andtwentysecondsislongtothosewhowatch——itisoftenimpossibletotelltotwoorthreefieldswhereitwillfinallysettle。 Allthiswhiletheriskthataballoonwouldrunofbeingriddledbybullets,shrapnel,orpom—pomshasnotbeentakenintoaccount,andastotheestimateofthisriskthereissomedifferenceofopinion。Theballooncorpsandtheartilleryapparentlyapproachthequestionwithdifferentbias。Ontheonehand,itisstatedwithperfecttruththatafreeballoon,whichisgenerallyeitherrisingorfalling,aswellasmovingacrosscountry,isahardobjecttohit,andamarksmanwouldonlystrikeitwithachanceorblunderingshot;but,ontheotherhandletustakethefollowingreportofthreeyearsago。 TheGermanartilleryhadbeentestingtheefficiencyofaquick—firinggunwhenusedagainstaballoon,andtheydecidedthatthelatterwouldhavenochanceofescapeexceptatnight。 AGermankite—balloonwaskeptmovingatanaltitudeof600 metres,andthegunstraineduponitweredistant3,000metres。 Itwasthenstatedthatafterthethirddischargeoftherapidfiringbatterytherangewasfound,whenallwasatonceoverwiththeballoon;for,notonlywasithitwitheverydischarge,butitwaspresentlysetonfireandannihilated。 But,inanycase,theantiquemodeofkeepingaballoonmooredatanyspotasapostofobservationmustbeabandonedinmodernwarfare。MajorBaden—Powell,speakingfrompersonalexperienceinSouthAfrica,hasshownhowdangerous,orelsehowuseless,suchaformofreconnaissancehasbecome。\"I remember,\"hesays,\"atthebattleofMagersfonteinmycompanywaslyingdowninextendedordertowardstheleftofourline。 Wewereperfectlysafefrommusketryfire,aswelay,perhaps,twomilesfromtheBoertrenches,whichwerebeingshelledbysomeofourgunscloseby。Theenemy’sartillerywaspracticallysilent。Presently,onlookinground,Idescriedourballoonawayoutbehindusabouttwomilesoff。Thenshesteadilyroseandmadeseveraltripstoagoodheight,butwhatcouldbeseenfromthatdistance?Whenalargenumberofourtroopswererangedupwithin800yardsofthetrenches,andmanymoreatallpointsbehindthem,whatusefulinformationcouldbeobtainedbymeansoftheballoonfourmilesoff?\" Thesameeminentauthorityinsistsonthenecessityofanobservingwarballoonmakingshortascents。Theballoon,inhisopinion,shouldbeallowedtoascendrapidlytoitsfullheight,andwithaslittledelayaspossiblebehauleddownagain。Undertheseconditionsitmaythenbewellworthtestingwhethertheprimitiveformofballoon,theMontgolfier,mightnotbethemostvaluable。Insteadofbeingmade,asthewarballoonisnow,offragilematerial,andfilledwithcostlygasdifficulttoprocure,andwhichhastobeconveyedinheavyandcumbersomecylinders,ahotairballooncouldberapidlycarriedbyhandanywherewhereafewmencouldpushtheirway。 Itisofstrongmaterial,readilymendediftorn,andcouldbeinflatedforshortascents,ifnotbymerebrushwood,thenbyaportableblastfurnaceandpetroleum。 Butthereisafurtheruseforballoonsinwarfarenotyetexploited。TheSiegeofParisshowedtheutilityoffreeballoons,andoccasionsarisewhentheirusemightbestillfurtherextended。Thewriterpointedoutthatitmighthavebeenverypossibleforanaeronautofexperience,bychoosingtherightweatherandtherightpositionalongtheBritishlines,tohaveskilfullymanoeuvredafreeballoonbymeansofuppercurrents,soastoconveyall—importantintelligencetobesiegedMafeking,andheprovedthatitwouldhavesufficediftheballooncouldhavebeen\"tacked\"acrosstheskytowithinsomefifteenmilesofthedesiredgoal。 Themodeofsignallingwhichheproposedwasbymeansofa\"collapsingdrum,\"aninstrumentofoccasionaluseintheNavy。