第18章

类别:其他 作者:Rev. J. M. Bacon字数:12141更新时间:18/12/18 14:00:38
Amodificationofthisinstrument,asemployedbythewriter,consistedofalight,spherical,drum—shapedframeoflargesize,which,whencoveredwithdarkmaterialandhungintheclearbelowthecarofaloftyballoon,couldbewellseeneitheragainstblueskyorgreyatagreatdistance。Theso—calleddrumcould,byaverysimplecontrivance,readilyworkedfromthecar,bemadetocollapseintoaveryinconspicuousobject,andthusbecapableofdisplayingMorseCodesignals。Alongpausewiththedrumextended——likethelongwaveofasignallingflag——woulddenotea\"dash,\"andashortpausea\"dot,\"andthesemotionswouldbeatonceintelligibletoanyoneacquaintedwiththenowuniversalMorseCodesystem。 Providedwithanapparatusofthekind,thewritermadeanascentfromNewburyatatimewhenthemilitarycampswerelyingonSalisburyPlainatadistanceofnearlytwentymilestothesouth—west。Thegroundwindupto2,500feetonstartingwasnearlyduenorth,andwouldhavedefeatedtheattempt;again,theairstreamblowingabovethatheightwasnearlydueeast,whichagainwouldhaveprovedunsuitable。Butitwasmanifestlypossibletoutilisethetwocurrents,andwithgoodlucktozig—zagone’scoursesoastocomewithineasysignallingdistanceofthevariouscamps;and,asamatteroffact,weactuallypassedimmediatelyoverBulfordCamp,withwhichweexchangedsignals,whiletwoothercampslayclosetorightandleftofus。Fortunefavouringus,wehadactuallyhitourmark,thoughitwouldhavebeensufficientfortheexperimenthadourcourselainwithintenmilesrightorleft。 Yetafurtherusefortheballooninwarfareremainsuntriedinthiscountry。ActingundertheadviceofexpertsintheService,thewriter,intheearlypartofthepresentyear,suggestedtotheAdmiraltythedesirabilityofexperimentingwithballoonsasameansofdetectingsubmarineenginesofwar。 Itiswellknownthatreefsandshoalscangenerallybeseenfromaclifformastheadfarmoreclearlythanfromthedeckorotherpositionnearthesurfaceofthewater。Wouldnot,then,aballoon,ifskilfullymanoeuvred,serveasavaluablepostofobservation?TheAdmiralty,inacknowledgingthecommunication,promisedtogivethemattertheirattention;butbythemonthofJunethePresshadannouncementsofhowtheself—sameexperimentshadbeensuccessfullycarriedthroughbyFrenchauthorities,whileafewdayslatertheAdmiraltywrote,\"Forthepresentnoneedisseenfortheuseofacaptiveballoontodetectsubmarines。\" Amongmanyandvariedballooningincidentswhichhaveoccurredtothewriter,therearesomewhichmaynotunprofitablybecomparedwithcertainexperiencesalreadyrecordedofotheraeronauts。Thunderstorms,aswitnessedfromaballoon,havealreadybeencasuallydescribed,anditmayreasonablybehopedthattheobservationswhichhave,undervaryingcircumstances,beenmadeathighaltitudesmaythrowsomeadditionallightonthisfamiliar,thoughsomewhatperplexing,phenomenon。 Tobeginwith,itseemsamootpointwhetheraballooncaughtinathunderstormis,orisnot,inanyspecialdangerofbeingstruck。Ithasbeenarguedthatimmunityundersuchcircumstancesmustdependuponwhetherasufficientlylongtimehaselapsedsincetheballoonlefttheearthtoallowofitsbecomingpositivelyelectrifiedbyinductionfromthecloudsorbyrainfallinguponitssurface。Buttherearemanyotherpointstobeconsidered。Thereistheconstantescapeofgasfromthemouth;thereisthemassofpointedmetalintheanchor;and,again,itisconceivablethataballoonrapidlydescendingoutofathunderstormmightcarrywithitachargeresidingonitsmoistenedsurfacewhichmightmanifestitselfdisastrouslyastheballoonreachedtheearth。 Instancesseemtohavebeennotinfrequentofballoonsencounteringthunderstorms;but,unfortunately,inmostcasestheobservershavenothadanyscientifictraining,ortheaccountswhicharetohandarethoseofthetypeofjournalistwhoischieflyinquestofsensationalcopy。 ThusthereisanaccountfromAmericaofaProfessorKingwhomadeanascentfromBurlington,Iowa,justasathunderstormwasapproaching,withtheresultthat,insteadofscuddingawaywiththewindbeforethestorm,hewasactually,asifbysomeattraction,drawnintoit。Onthishisaimwastopiercethroughthecloudabove,andthenfollowsadescriptionwhichitishardtorealise:——\"Therecamedowninfrontofhim,andapparentlynotmorethan50feetdistant,agranddischargeofelectricity。\"Thenhefeelsthecarlifted,thegassuddenlyexpandstooverflowing,andtheballoonishurledthroughthecloudwithinconceivablevelocity,thishappeningseveraltimes,withtremendousoscillationsofthecar,untiltheballoonisbornetoearthinatorrentofrain。Wefancythatmanypracticalballoonistswillhardlyendorsethisdescription。 Butwehaveanother,relatingtooneofthemostdistinguishedaeronauts,M。EugeneGodard,who,inanascentwithlocaljournalists,wascaughtinathunderstorm。Herewearetold——presumablybythejournalists——that\"twicethelightningflashedwithinafewyardsoftheterror—strickencrew。\" Onceagain,inanascentatDerby,aspectatorwrites:——\"Thelightningplayeduponthesphereoftheballoon,lightingitupandmakingthingsvisiblethroughit。\"This,however,onemustsuppose,canhardlyapplytotheballoonwhenliberated。 Butagraphicdescriptionofaverydifferentcharactergiveninthe\"QuarterlyJournaloftheRoyalMeteorologicalSociety\" forJanuary,1901,isofrealvalue。ItappearsthatthreelieutenantsofthePrussianBalloonCorpstookchargeofaballoonthatascendedatBerlin,and,whenataheightof2,300 feet,becameenvelopedinthemist,throughwhichonlyoccasionalglimpsesofearthwereseen。Atthispointasharp,cracklingsoundwasheardatthering,likethesparkingofahugeelectricalmachine,and,lookingup,thevoyagersbeheldsparksapparentlysomehalf—inchthick,andovertwofeetinlength,playingfromthering。Thunderwasheard,but——andthismayhavesignificance——onlybeforeandaftertheabovephenomenon。 AnotherinstructiveexperienceisrecordedoftheyoungerGreeninanascentwhichhemadefromFrankfort—on—the—Maine。Onthisoccasionherelatesthatheencounteredathunderstorm,andataheightof4,400feetfoundhimselfatthelevelwherethestormcloudsweredischargingthemselvesinadeluge。Heseemstohavehadnodifficultyinascendingthroughthestormintotheclearskyabove,whereabreezefromanotherquarterquicklycarriedhimawayfromthestormcentre。 Thisco—existence,orconflictofoppositecurrents,isheldtobethecommoncharacteristic,ifnotthemaincause,ofthunderstorms,andtallieswiththefollowingpersonalexperience。ItwasintypicalJulyweatherof1900thatthewriterandhisson,accompaniedbyAdmiralSirEdmundFremantleandMr。PercivalSpencer,madeaneveningascentfromNewbury。 Ithadbeenadayofstorms,butabout5p。m。,afterwhatappearedtobeaclearingshower,theskybrightened,andwesailedupintoacloudlessheaven。Thewind,at3,000feet,wastravellingatsomethirtymilesanhour,anderethedistanceoftenmileshadbeencoveredaformidablethunderpackwasseenapproachingandcomingupdeadagainstthewind。 Nothingcouldbemoreevidentthanthattheballoonwastravellingrapidlywithalowerwind,whilethestormwasbeingborneequallyrapidlyonanupperanddiametricallyoppositecurrent。Itprovedoneofthemostseverethunderstormsrememberedinthecountry。ItbroodedforfivehoursoverDevizes,afewmilesahead。Ahomesteadonourrightwasstruckandburnedtotheground,whileonourlefttwosoldierswerekilledonSalisburyPlain。Theskyimmediatelyoverheadwas,ofcourse,hiddenbythelargeglobeoftheballoon,butaroundandbeneathusthestormseemedtogatherinabluegreymist,whichquicklybroadenedanddeepenedtill,almostbeforewecouldrealiseit,wefoundourselvesintheveryheartofthestorm,thelightningplayingallaroundus,andthesharphailstingingourfaces。 Thecountrymenbelowdescribedtheballoonasapparentlyenvelopedbythelightning,butwithourselves,thoughtheflasheswereincessant,andonallsides,thereverberationsofthethunderwerenotremarkable,beingratherbriefexplosionsinwhichtheyresembledthethunderclapsnotinfrequentlydescribedbytravellersonmountainheights。 Theballoonwasnowdescendingfromadoublecause:theweightofmoisturesuddenlyaccurnulatedonitssurface,andtheveryobviousdownrushofcoldairthataccompaniedthestormofpeltinghail。Withaverylimitedstoreofballast,itseemedimpossibletomakeafurtherascent,norwasthisdesirable。 Thesignallingexperimentsonwhichwewereintentcouldnotbecarriedoninsuchweather。Theonlycoursewastodescend,andthoughthiswasnotatoncepracticable,owingtoSavernakeForestbeingbeneathus,weeffectedasafelandinginthefirstavailableclearing。 Ashasbeenmentioned,Mr。Glaisherandotherobservershaverecordedseveralremarkableinstancesofoppositewindcurrentsbeingmetwithatmoderatealtitudes。None,however,canhavebeenmorenoteworthyorsurprisingthanthefollowingexperienceOfthewriteronWhitMondayof1899。Theascentwasunderanovercastsky,fromtheCrystalPalaceat3p。m。,atwhichhouracolddrizzlewassettlinginwithamoderatebreezefromtheeast。Thus,startingfromtheusualfillinggroundnearthenorthtower,theballoonsailedoverthebodyofthePalace,andthenceoverthesuburbstowardsthewesttilllostinthemist。Wethenascendedthrough1,500feetofdense,wettingcloud,and,emerginginbrightsunshine,continuedtodriftfortwohoursatanaveragealtitudeofsome3,000feet;1,000feetbelowuswastheill—defined,everchanginguppersurfaceofthedensecloudfloor,anditwasnolongerpossibletodetermineourcourse,whichwethereforeassumedtohaveremainedunchanged。Atlength,however,asameasureofprudence,wedeterminedtodescendthroughthecloudssufficientlytolearnsomethingofourwhereabouts,whichwereasonablyexpectedtobesomewhereinSurreyorBerks。Onemerging,however,belowthecloud,thefirstobjectthatloomedoutofthemistirnmediatelybelowuswasacargovessel,intheriggingofwhichourtrailropewasentanglingitself。OnlybydegreesthefactdawneduponusthatwewereintheestuaryoftheThames,andbeatinguptowardsLondononceagainwithancastwind。Thusitbecameevidentthatatthehigherlevel,unknowntoourselves,wehadbeenheadedbackonourcourse,fortwohours,byawinddiametricallyopposedtothatblowingontheground。 Tworecentdevelopmentsofthehot—airwarballoonsuggestgreatpossibilitiesinthenearfuture。Onetakestheformofasmallcaptive,carryingaloftaphotographiccameradirectedandoperatedelectricallyfromtheground。Theotherisaself—containedpassengerballoonoflargedimensions,carryingincompletesafetyaspecialpetroleumburnerofgreatpower。 ThesenewandimportantdeparturesaremainlyduetothemechanicalgeniusofMr。J。N。Maskelyne,whohaspatentedandperfectedtheminconjunctionwiththewriter。 CHAPTERXXVIII。THECONSTITUTIONOFTHEAIR。 Somefairideaoftheconditionsprevailingintheupperairmayhavebeengatheredfromthemanyandvariousobservationsalreadyrecorded。Statingthecasebroadly,wemayassertthatthesameatmosphericchangeswithwhichwearefamiliarattheleveloftheeartharetobefoundalsoatallaccessibleheights,equallyextensiveandequallysudden。 Standingonanopenheathonagustyday,wemayoftennotetherhythmicbuffetingofthewind,resemblingtheassaultofrollingbillowsofair。Theevidenceofthesebillowshasbeenactuallytracedfaraloftinballoontravel,whenaeronauts,lookingdownonawind—sweptsurfaceofcloud,haveobservedthissurfacetobethrownintoaseriesofrollsofvapour,whichwerebutvastandveritablewavesofair。Theintervalbetweensuccessivecrestsofthesewaveshasononeoccasionbeenestimatedatapproximatelyhalfamile。Wehaveseenhowtheseairstreamssometimesholdwideandindependentswayatdifferentlevels。Wehaveseen,too,howtheysometimesmeetandmingle,notinfrequentlyattendedwithelectricaldisturbanceThroughbroaddriftsofairminorairstreamswouldseemoftenliterallyto\"thread\"theirway,breakngupintofilamentsorwanderingrillsofair。InthevoyageacrossSalisburyPlainlatelydescribed,whiletheballoonwasbeingcarriedwiththemoresluggishcurrent,anumberofsmallparachutesweredroppedoutatfrequentintervalsandcarefullywatched。Thesewouldcommonlyattendtheballoonforalittlewhile,until,gettingintosomeminorairstream,theywouldsuddenlyandrapidlydivergeatsuchwideanglesastosuggestthatcrossingouractualcoursethereweresidepaths,downwhichthesmallerbodiesbecamewafted。 Onanotheroccasionthewritermetwithstronglymarkedandaltogetherexceptionalevidenceofthevehemenceandpersistenceoftheseminoraerialstreamlets。ItwasonanoccasioninAprilweather,whenaheavyovercastskyblottedouttheupperheavens。Inthecloudlevelsthewindwassomewhatsluggish,andforanhourwetravelledatanaveragespeedofalittleovertwentymilesanhour,neverhigherthan3,000feet。Atthispoint,whileflyingoverHertfordshire,wethrewoutsufficientballasttocausetheballoontoriseclearofthehazylowerair,andcomingunderthefullinfluenceofthesun,theninthemeridian,weshotupwardsatconsiderablespeed,andsoonattainedanaltitudeofthreemiles。Butforaconsiderableportionofthisclimb——while,infact,wewereascendingthroughlittlelessthanamileofourupwardcourse——wewereassailedbyimpetuouscrosscurrents,whichwhistledthroughcarandriggingandsmoteusfairlyonthecheek。Itwasaltogetheranovelexperience,andthemoreremarkablefromthefactthatourmainonwardcoursewasnotappreciablydiverted。 Thenwegotabovethesecurrents,andremainedatourmaximumlevel,whilewefloated,stillatonlyamoderatespeed,thelengthofacounty。Thedescentthenbegan,andonceagain,whilewedroppedthroughthesamedisturbedregion,thesamefar—reachingandobtrusivecross—currentassailedus。Itwasquiteobviousthatthevehementcurrentsweretooslendertotelllargelyuponthehugesurfaceoftheballoon,asitwasbeingsweptsteadilyonwardsbythemainwind,whichnevervariedindirectionfromgroundlevelsuptothegreatestheightattained。 ThisexperienceisbutconfirmationofthestoryofthewindtoldbythewindgaugesontheForthBridge。Herethemaximumpressuremeasuredonthelargegaugeof300squarefeetiscommonlyconsiderablylessthanthatonthesmallergauge,suggestingthatthelattermustbeduetothreadsofairoflimitedareaandhighvelocity。 Furtherandveryvaluablelightisthrownonthepeculiarwaysofthewind,nowbeingconsidered,byProfessorLangleyinthespecialresearchesofhistowhichreferencehasalreadybeenmade。Thiseminentobserverandmathematician,suspectingthattheold—fashionedinstruments,whichonlytoldwhatthewindhadbeendoingeveryhour,oratbesteveryminute,gavebutamostimperfectrecord,constructeddelicategauges,whichwouldrespondtoeveryimpulseandgivereadingsfromsecondtosecond。 Inthiswayheestablishedthefactthatthewind,farfrombeingabodyofevenapproximateuniformity,isundermostordinaryconditionsirregularalmostbeyondconception。 Further,thatthegreaterthespeedthegreaterthefluctuations,sothatahighwindhastoberegardedas\"airmovinginatumultuousmass,\"thevelocityatonemomentperhapsfortymilesanhour,thendiminishingtoanalmostinstantaneouscalm,andthenresuming。\"Infact,intheverynatureofthecase,windisnottheresultofonesimplecause,butofaninfinitenumberofimpulsesandchanges,perhapslongpassed,whicharepreservedinit,andwhichdieonlyslowlyaway。\" Whenwecometotakeobservationsoftemperaturewefindtheconditionsintheatmosphereaboveustobeatfirstsightnotalittlecomplex,andaltogetherdifferentindayandnighthours。Fromobservationsalreadyrecordedinthisvolume——notablythoseofGayLussac,Welsh,andGlaisher——ithasbeenmadetoappearthat,inascendingintotheskyindaytime,thetemperatureusuallyfallsaccordingtoagenerallaw;buttherearefoundregionswherethefalloftemperaturebecomesarrested,suchregionsbeingcommonly,thoughbynomeansinvariably,associatedwithvisiblecloud。Itisprobable,however,thatitwouldbemorecorrectnottointerpretthepresenceofcloudascausingmanifestationofcold,butrathertoregardthemeetingofwarmandcoldcurrentsasthecauseofcloud。 Thewriterhasexperimentedintheupperregionswithaspecialformofairthermometerofgreatsensibility,designedtorespondrapidlytoslightvariationsoftemperature。Testingthisinstrumentononeoccasioninaroomofequablewarmth,andwithoutdraughts,hewaspuzzledbyseeingtheindexinacapillarytubesuddenlymountingrapidly,duetosomecausewhichwasnotapparent,tillitwasnoticedthattheparlourcat,attractedbytheproceedings,hadapproachedneartheapparatus。Thebehaviourofthisinstrumentwhenslungintheclearsomedistanceoverthesideoftheballooncar,andcarefullywatched,suggestsbyitsfitful,sudden,andrapidchangesthatwarmercurrentsareoftenmakingtheirwayinsuchslenderwanderingrillsashavebeenalreadypicturedaspermeatingthebroaderairstreams。Duringnighthoursconditionsarereversed。Thewarmerairradiatedofftheearththroughthedayhasthenascended。Itwillbefoundatdifferentheights,lyinginpoolsorstrata,possiblyresemblinginform,couldtheybeseen,massesofvisiblecloud。 Thewriterhasgatheredfromnightvoyagesinstructiveandsuggestivefactswithreferencetotheascentofairstreams,duetodifferencesoftemperature,particularlyoverLondonandthesuburbs,anditisconceivablethatinsuchascendingstreamsmaylieameansofdealingsuccessfullywithvisitationsofsmokeandfog。 Onelessontaughtbyballoontravelhasbeenthatfogorhazewillcomeorgoinobediencetotemperaturevariationsatlowlevels。ThusthickhazehaslainoverLondon,moreparticularlyoverthelowerparts,atsundown。Thenthroughnighthours,asthetemperatureofthelowerairhasbecomeequalised,thehazehascompletelydisappeared,butonlytoreassertitselfatdawn。 AdescriptionoftheveryimpressiveexperienceofanightsailoverLondonhasbeenreserved,butshouldnotbealtogetheromitted。Glaisher,writingofthespectacleasheobserveditnearlyfortyyearsago,describesLondonseenatnightfromaballoonatadistanceasresemblingavastconflagration。Whenactuallyoverthetown,amainthoroughfareliketheCommercialRoadshoneuplikealineofbrilliantfire;but,travellingwestward,OxfordStreetpresentedanappearancewhichpuzzledhim。\"Herethetwothicklystuddedrowsofbrilliantlightswereseenoneithersideofthestreet,withanarrow,darkspacebetween,andthisdarkspacewasbounded,asitwere,onbothsidesbyabrightfringelikefrostedsilver。\"Presentlyhediscoveredthatthisricheffectwascausedbythebrightilluminationoftheshoplightsonthepavements。\" London,asseenfromaballoononaclearmoonlightnightinAugustayearago(1901),woreasomewhatalteredappearance。 Therewerethefairylampstracingoutthestreets,which,thoughdarkcentred,woretheirsilverlining;butinirregularpatchesawhiterlightfromelectricarclampsbroadenedandbrightenedandshoneoutlikesomepyrotechnicdisplayabovetheblackhousetops。Throughthevasttownranablank,blackchannel,theriver,windingonintodistance,crossedhereandtherebybridgesshowingasbrightbands,andwithbrightspotsoccasionallytomarkwherelaytherivercraft。Butwhatwasmoststrikingwasthesilence。ThoughthenoiseofLondontrafficasheardfromaballoonhasdiminishedoflateyearsowingtothebetterpaving,yetindayhourstheroarofthestreetsishearduptoagreatheightasahard,harsh,grindingdin。Butatnight,afterthelast’bushasceasedtoply,andbeforethemarketcartsbeginlumberingin,theballoonist,ashesailsoverthetown,mightimaginethathewastraversingaCityoftheDead。 Itisatsuchtimesthatashoutthroughaspeakingtrumpethasamoststartlingeffect,andmoreparticularlyablastonahorn。Inthiscaseafteranintervalofsomesecondsawildnotewillbeflungbackfromthehouse—topsbelow,answeredandre—answeredonallsidesasitechoesfromrooftoroof——awild,weirduproarthatawakessuddenly,andthendiesoutslowlyfaraway。 Experimentswithechoesfromaballoonhaveprovedinstructive。 If,whenridingataheight,say,of2,000feet,achargeofgun—cottonbefiredelectrically100feetbelowthecar,thereport,thoughreallyasloudasacannon,soundsnomorethanamerepistolshot,possiblypartlyowingtothegreaterrarityoftheair,butchieflybecausethesound,havingnobackgroundtoreflectit,simplyspendsitselfintheair。Then,alwaysandunderallconditionsofatmospheresoever,thereensuesabsolutesilenceuntilthetimefortheechobackfromearthhasfullyelapsed,whenadeafeningoutburstofthunderrisesfrombelow,rollingonoftenformorethanhalfaminute。Twonoteworthyfacts,atleast,thewriterhasestablishedfromaverylargenumberoftrials:first,thatthetheoryofaerialechoesthrownbackfromemptyspace,whichphysicistshaveheldtoexistconstantly,andtobepartofthecauseofthunder,willhavetobeabandoned;and,secondly,thatfromsomecauseyettobefullyexplainedtheechobackfromtheearthisalwaysbehinditstime。 Butballoonshaverevealedfurthersuggestivefactswithregardtosound,andmoreparticularlywithregardtothevaryingacousticpropertiesoftheair。Itisafamiliarexperiencehowdistantsoundswillcomeandgo,risingandfalling,oftenbeingwaftedoverextraordinarydistances,andagainfailingaltogether,orsometimesbeinglostatnearrange,butappearinginstrengthfurtheraway。Afreeballoon,movingintheprofoundsilenceoftheupperair,becomesanadmirablesoundobservatory。Itmaybeclearlydetectedthatincertainconditionsofatmosphere,atleast,therearewhatmaybeconceivedtobeaerialsoundchannels,throughwhichsoundsare,momentarilyconveyedwithabnormalintensity。Thisphenomenondoesbutservetogiveanintelligiblepresentmentoftheunseenconditionsexistingintherealmofair。 Itwouldbereasonabletosupposethatwereaneyesoconstitutedastobeabletosee,say,cumulusmassesofwarmerair,stratamottledwithtracesofothergases,andbedsofinvisiblematterinsuspension,onemightsupposethatwhatwedeemtheclearestskywouldthenappearfleckedwithformsasmanyandvariousasthecloudsthatadornoursummerheavens。 Butthereismatterinsuspensionintheatmospherewhichisveryfarfrominvisible,andwhichinthecaseoflargetownsisverycommonlylyinginthickstrataoverhead,stoppingbackthesunlight,andformingthenucleusroundwhichnoisomefogsmayform。Experimentingwithsuitableapparatus,thewriterhasfoundonastillafternooninMay,at2,000feetaboveKingstoninSurrey,thattheairwaschargedfarmoreheavilywithdustthanthatoftheLondonstreetsthenextday;and,again,athalfamileabovethecityinthemonthofAugustlastdust,muchofitbeingofagrossandevenfibrousnature,wasfarmoreabundantthanongrassenclosuresinthetownduringtheforenoonofthedayfollowing。 AnattempthasbeenmadetoincludeEnglandinaseriesofinternationalballoonascentsarrangedexpresslyforthepurposeoftakingsimultaneousobservationsatalargenumberofstationsoverEurope,bywhichmeansitishopedthatmuchfreshknowledgewillbeforthcomingwithrespecttotheconstitutionoftheatmosphereuptothehighestlevelsaccessiblebyballoonsmannedandunmanned。ItisverymuchtoberegrettedthatinthecaseofEnglandtheattemptherespokenofhasrestedentirelyonprivateenterprise。FirstandforemostinpersonalliberalityandtheworkoforganisationmustbementionedMr。P。Y。Alexander,whosezealintheprogressofaeronauticsissecondtononeinthiscountry。 TwicethroughhiseffortsEnglandhasbeenrepresentedintheimportantworkforwhichContinentalnationshavenodifficultyinobtainingpublicgrants。ThefirstoccasionwasonNovember8th,1900,whenthewriterwasprivilegedtooccupyaseatintheballoonfurnishedbyMr。Alexander,andequippedwiththemostmoderntypeofinstruments。ItwasastormyandfastvoyagefromtheCrystalPalacetoHalstead,inEssex,48milesin40minutes。Simultaneouslywiththis,Mr。AlexanderdismissedanunmannedballoonfromBath,whichascended8,000 feet,andlandedatCricklade。OtherballoonswhichtookpartinthecombinedexperimentweretwofromParis,threefromChalaisMeudon,threefromStrasburg,twofromVienna,twofromBerlin,andtwofromSt。Petersburg。 Thesectionofourcountrymenspeciallyinterestedinaeronautics——agrowingcommunity——isrepresentedbytheAeronauticalSociety,formedin1865,withtheDukeofArgyllforpresident,andforthirtyyearsunderthemostenergeticmanagementofMr。F。W。Brearey,succeedingwhomashon。secs。 havebeenMajorBaden—PowellandMr。EricS。Bruce。Mr。 Breareywasoneofthemostsuccessfulinventorsofflyingmodels。Mr。Chanute,speakingasPresidentoftheAmericanSocietyofCivilEngineers,paidhimahighandwell—deservedcomplimentinsayingthatitwasthroughhisinfluencethataerialnavigationhadbeenclearedofmuchrubbishandplaceduponascientificandfirmbasis。 Anothercommunitydevotingitselftothepursuitofballoontripsandmattersaeronauticalgenerallyisthenewly—formedAeroClub,ofwhomoneofthemostprominentandenergeticmembersistheHon。C。S。Rolls。 IthadbeenannouncedthatM。Santos—DumontwouldbringanairshiptoEngland,andduringthesummerofthepresentyearwouldgiveexhibitionsofitscapability。ItwasevenrumouredthathemightcircleroundSt。Paul’sandaccomplishotheraerialfeatsunknowninEngland。ThepromisewasfulfilledsofarasbringingtheairshiptoEnglandwasconcerned,foroneofhisvesselswhichhadseenservicewasdepositedattheCrystalPalace。Insomemysteriousmanner,however,neversufficientlymadecleartothepublic,thismachinewasonemorningfounddamaged,andM。Santos—Dumonthaswithdrawnfromhisproposedengagements。 Inthusdoingheleftthefieldopentooneofourowncountrymen,who,inhisfirstattemptatflightwithanairshipofhisowninventionandconstruction,hasprovedhimselfnounworthyrivalofthewealthyyoungBrazilian。 Mr。StanleySpencer,inaverybriefspaceoftime,designedandbuiltcompletelyintheworkshopsofthefirmanelongatedmotorballoon,75feetlongby20feetdiameter,workedbyascrewandpetrolmotor。Thismotorisplacedintheprow,25 feetawayfrom,andinfrontof,thesafetyvalve,bywhichprecautionanydangerofignitingtheescapinggasisavoided。 Should,however,acollapseofthemachinearisefromanycause,thereisanarrangementforthrowingtheballoonintotheformofaparachute。Further,thereisprovidedmeansforadmittingairatwillintotheballoon,bywhichthenecessityformuchballastisobviated。 Mr。Spencerhavingfilledtheballoonwithpurehydrogen,madehisfirsttrialwiththismachinelateinaneveningattheendofJune。TheperformanceofthevesselisthusdescribedintheWestminsterGazette:——\"Thehugeballoonfilledslowly,sothatthelightwasrapidlyfailingwhenatlastthedoorsofthebigshedslidopenandtheshipwasbroughtcarefullyout,hermotorstarted,andhermaidenvoyagecommenced。WithMr。