the dominion of the air-第25部分

快捷操作: 按键盘上方向键 ← 或 → 可快速上下翻页 按键盘上的 Enter 键可回到本书目录页 按键盘上方向键 ↑ 可回到本页顶部! 如果本书没有阅读完，想下次继续接着阅读，可使用上方 "收藏到我的浏览器" 功能 和 "加入书签" 功能！


aluable　aid　to　the　uses　of　philosophy；　and　rescue　it　from　the　impending　degradation　of　continuing　a　toy　fit　only　to　be　exhibited　or　to　administer　to　the　pleasures　of　the　curious　and　lovers　of　adventure。〃

The　words　of　the　same　authority　as　to　the　possible　practical　development　of　the　balloon　as　an　aerial　machine　should　likewise　be　quoted；　and　will　appear　almost　prophetic。　　〃In　England　the　subject　of　aero…station　has　made　but　little　progress；　and　no　valuable　invention　has　arisen　to　facilitate　travelling　in　the　air。　　In　all　my　ascents　I　used　the　balloon　as　I　found　it。　　The　desire　which　influenced　me　was　to　ascend　to　the　higher　regions　and　travel　by　its　means　in　furtherance　of　a　better　knowledge　of　atmospheric　phenomena。　　Neither　its　management　nor　its　improvement　formed　a　part　of　my　plan。　　I　soon　found　that　balloon　travelling　was　at　the　mercy　of　the　wind；　and　I　saw　no　probability　of　any　method　of　steering　balloons　being　obtained。　　It　even　appeared　to　me　that　the　balloon　itself；　admirable　for　vertical　ascents；　was　not　necessarily　a　first　step　in　aerial　navigation；　and　might　possibly　have　no　share　in　the　solution　of　the　problem。　　It　was　this　conviction　that　led　to　the　formation　of　the　Aeronautical　Society　a　few　years　since　under　the　presidency　of　the　Duke　of　Argyll。　　In　the　number　of　communications　made　to　this　society　it　is　evident　that　many　minds　are　taxing　their　ingenuity　to　discover　a　mode　of　navigating　the　air；　all　kinds　of　imaginary　projects　have　been　suggested；　some　showing　great　mechanical　ingenuity；　but　all　indicating　the　want　of　more　knowledge　of　the　atmosphere　itself。　　The　first　great　aim　of　this　society　is　the　connecting　the　velocity　of　the　air　with　its　pressure　on　plane　surfaces　at　various　inclinations。

〃There　seems　no　prospect　of　obtaining　this　relation　otherwise　than　by　a　careful　series　of　experiments。〃



CHAPTER　XIV。　THE　HIGHEST　ASCENT　ON　RECORD。


Mr。　Glaisher's　instrumental　outfit　was　on　an　elaborate　and　costly　scale；　and　the　programme　of　experimental　work　drawn　up　for　him　by　the　Committee　of　the　British　Association　did　not　err　on　the　side　of　too　much　modesty。　　In　the　first　place　the　temperature　and　moisture　of　the　atmosphere　were　to　be　examined。　　Observations　on　mountain　sides　had　determined　that　thermometers　showed　a　decrease　of　1　degree　F。　for　every　300　feet；　and　the　accuracy　of　this　law　was　particularly　to　be　tested。　　Also；　investigations　were　to　be　made　as　to　the　distribution　of　vapour　below　the　clouds；　in　them；　and　above　them。　　Then　careful　observations　respecting　the　dew　point　were　to　be　undertaken　at　all　accessible　heights；　and；　more　particularly；　up　to　those　heights　where　man　may　be　resident　or　troops　may　be　located。　　The　comparatively　new　instrument；　the　aneroid　barometer；　extremely　valuable；　if　only　trustworthy；　by　reason　of　its　sensibility；　portability　and　safety；　was　to　be　tested　and　compared　with　the　behaviour　of　a　reliable　mercurial　barometer。　　Electrical　conditions　were　to　be　examined；　the　presence　of　ozone　tested；　the　vibration　of　a　magnet　was　again　to　be　resorted　to　to　determine　how　far　the　magnetism　of　the　earth　might　be　affected　by　height。　　The　solar　spectrum　was　to　be　observed；　air　was　to　be　collected　at　different　heights　for　analysis；　clouds；　also　upper　currents；　were　to　be　reported　on。　　Further　observations　were　to　be　made　on　sound；　on　solar　radiation；　on　the　actinic　action　of　the　sun；　and　on　atmospheric　phenomena　in　general。

All　this　must　be　regarded　as　a　large　order　where　only　a　very　limited　number　of　ascents　were　contemplated；　and　it　may　be　mentioned　that　some　of　the　methods　of　investigation；　as；　for　instance；　the　use　of　ozone　papers；　would　now　be　generally　considered　obsolete；　while　the　mechanical　aspiration　of　thermometers　by　a　stream　of　air；　which；　as　we　have　pointed　out；　was　introduced　by　Welsh；　and　which　is　strongly　insisted　on　at　the　present　day；　was　considered　unnecessary　by　Mr。　Glaisher　in　the　case　of　wet　and　dry　bulb　hygrometers。　　The　entire　list　of　instruments；　as　minutely　described　by　the　talented　observer；　numbered　twenty…two　articles；　among　which　were　such　irreproachable　items　as　a　bottle　of　water　and　a　pair　of　scissors。

The　following　is　a　condensed　account；　gathered　from　Mr。　Glaisher's　own　narrative；　of　his　first　ascent；　which　has　been　already　briefly　sketched　in　these　pages　by　the　hand　of　Mr。　Coxwell。　　Very　great　difficulties　were　experienced　in　the　inflation；　which　operation　appeared　as　if　it　would　never　be　completed；　for　a　terrible　W。S。W。　wind　was　constantly　blowing；　and　the　movements　of　the　balloon　were　so　great　and　so　rapid　that　it　was　impossible　to　fix　a　single　instrument　in　its　position　before　quitting　the　earth；　a　position　of　affairs　which；　says　Mr。　Glaisher；　〃was　by　no　means　cheering　to　a　novice　who　had　never　before　put　his　foot　in　the　car　of　a　balloon；〃　and　when；　at　last；　at　9。42　a。m。；　Mr。　Coxwell　cast　off；　there　was　no　upward　motion；　the　car　simply　dragging　on　its　side　till　the　expiration　　of　a　whole　minute；　when　the　balloon　lifted；　and　in　six　minutes　reached　the　first　cloud　at　an　altitude　of　4；467　feet。　　This　cloud　was　passed　at　5；802　feet；　and　further　cloud　encountered　at　2；000　feet　further　aloft。　　Four　minutes　later；　the　ascent　proceeding；　the　sun　shone　out　brightly；　expanding　the　balloon　into　a　perfect　globe　and　displaying　a　magnificent　view；　which；　however；　the　incipient　voyager　did　not　allow　himself　to　enjoy　until　the　instruments　were　arranged　in　due　order；　by　which　time　a　height　of　10；000　feet　was　recorded。

Mr。　Glaisher　apparently　now　had　opportunity　for　observing　the　clouds；　which　he　describes　as　very　beautiful；　and　he　records　the　hearing　of　a　band　of　music　at　a　height　of　12；709　feet；　which　was　attained　in　exactly　twenty　minutes　from　the　start。　　A　minute　later　the　earth　was　sighted　through　a　break　in　the　clouds；　and　at　16；914　feet　the　clouds　were　far　below；　the　sky　above　being　perfectly　cloudless；　and　of　an　intense　Prussian　blue。

By　this　time　Mr。　Glaisher　had　received　his　first　surprise；　as　imparted　by　the　record　of　his　instruments。　　At　starting；　the　temperature　of　the　air　had　stood　at　59　degrees。　　Then　at　4；000　feet　this　was　reduced　to　45　degrees；　and；　further；　to　26　degrees　at　10；000　feet；　when　it　remained　stationary　through　an　ascent　of　3；000　feet　more；　during　which　period　both　travellers　added　to　their　clothing；　anticipating　much　accession　of　cold。　　However；　at　15；500　feet　the　temperature　had　actually　risen　to　31　degrees；　increasing　to　no　less　than　42　degrees　at　19；500　feet。

Astonishing　as　this　discovery　was；　it　was　not　the　end　of　the　wonder；　for　two　minutes　later；　on　somewhat　descending；　the　temperature　commenced　decreasing　so　rapidly　as　to　show　a　fall　of　27　degrees　in　26　minutes。　　As　to　personal　experiences；　Mr。　Glaisher　should　be　left　to　tell　his　own　story。　　〃At　the　height　of　18；844　feet　18　vibrations　of　a　horizontal　magnet　occupied　26。8　seconds；　and　at　the　same　height　my　pulse　beat　at　the　rate　of　100　pulsations　per　minute。　　At　19；415　feet　palpitation　of　the　heart　became　perceptible；　the　beating　of　the　chronometer　seemed　very　loud；　and　my　breathing　became　affected。　　At　19；435　feet　my　pulse　had　accelerated；　and　it　was　with　increasing　difficulty　that　I　could　read　the　instruments；　the　palpitation　of　the　heart　was　very　perceptible；　the　hands　and　lips　assumed　a　dark　bluish　colour；　but　not　the　face。　　At　20；238　feet　28　vibrations　of　a　horizontal　magnet　occupied　43　seconds。　　At　21；792　feet　I　experienced　a　feeling　analogous　to　sea…sickness；　though　there　was　neither　pitching　nor　rolling　in　the　balloon；　and　through　this　illness　I　was　unable　to　watch　the　instrument　long　enough　to　lower　the　temperature　to　get　a　deposit　of　dew。　　The　sky　at　this　elevation　was　of　a　very　deep　blue　colour；　and　the　clouds　were　far　below　us。　　At　22；357　feet　I　endeavoured　to　make　the　magnet　vibrate；　but　could　not；　it　moved　through　arcs　of　about　20　degrees；　and　then　settled　suddenly。

〃Our　descent　began　a　little　after　11　a。m。；　Mr。　Coxwell　experiencing　considerable　uneasiness　at　our　too　close　vicinity　to　the　Wash。　　We　came　down　quickly　from　a　height　of　16；300　feet　to　one　of　12；400　feet　in　one　minute；　at　this　elevation　we　entered　into　a　dense　cloud　which　proved　to　be　no　less　than　8；000　feet　in　thickness　and　whilst　passing　through　this　the　balloon　was　invisible　from　the　car。　　From　the　rapidity　of　the　descent　the　balloon　assumed　the　shape　of　a　parachute；　and　though　Mr。　Coxwell　had　reserved　a　large　amount　of　ballast；　which　he　discharged　as　quickly　as　possible；　we　collected　so　much　weight　by　the　condensation　of　the　immense　amount　of　vapour　through　which　we　passed　that；　notwithstanding　all　his　exertions；　we　came　to　the　earth　with　a　very　considerable　shock；　which　broke　nearly　all　the　instruments。。。。　The　descent　took　place　at　Langham；　near　Oakham。〃

Just　a　month　later　Mr。　Glaisher；　bent　on　a　yet　loftier　climb；　made　his　second　ascent；　again　under　Mr。　Coxwell's　guidance；　and　again　from　Wolverhampton。　　Besides　attending　to　his　instruments　he　found　leisure　to　make　other　chance　notes　by　the　way。　　He　was　particularly　struck　by　the　beauty　of　masses　of　cloud；　which；　by　the　time　12；000　feet　were　reached；　were　far　below；　〃presenting　at　times　mountain　scenes　of　endless　variety　and　grandeur；　while　fine　dome…like　clouds　dazzled　and　charmed　the　eye　with　alternations　and　brilliant　effects　of　light　and　shade。〃

When　a　height　of　about　20；000　feet　had　been　reached　thunder　was　heard　twice　over；　coming　from　below；　though　no　clouds　could　be　seen。　　A　height　of　4；000　feet　more　was　attained；　and　shortly　after　this　Mr。　Glaisher　speaks　of　feeling　unwell。　　It　was　difficult　to　obtain　a　deposit　of　dew　on　the　hygrometer；　and　the　working　of　the　aspirator　became　troublesome。　　While　in　this　region　a　sound　like　that　of　loud　thunder　came　from　the　sky。　　Observations　were　practically　completed　at　this　point；　and　a　speedy　and　safe　return　to　earth　was　effected；　the　landing　being　at　Solihull；　seven　miles　from　Birmingham。

It　was　on　the　5th　of　September　following　that　the　same　two　colleagues　carried　out　an　exploit　which　will　always　stand　alone　in　the　history　of　aeronautics；　namely；　that　of　ascending　to　an　altitude　which；　based　on　the　best　estimate　they　were　able　to　make；　they　calculated　to　be　no　less　than　seven　miles。　　Whatever　error　may　have　unavoidably　come　into　the　actual　estimate；　which　is　to　some　extent　conject