the dominion of the air-第60章

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rry　out　any　required　manoeuvre　in　such　atmospheric　conditions　as　generally　prevail。　　If；　even　in　calm　and　favourable　weather；　more　often　than　not　motors　break　down；　or　gear　carries　away；　what　hope　is　there　for　any　aerial　craft　which　would　attempt　to　battle　with　such　wind　currents　as　commonly　blow　aloft？

And　when　we　turn　to　the　balloon　proper；　are　chances　greatly　improved？　　The　eminently　practical　aeronaut；　John　Wise；　as　was　told　in　Chapter　XII。；　prepared　a　scheme　for　the　reduction　of　Vera　Cruz　by　the　agency　of　a　balloon。　　Let　us　glance　at　it。　　A　single　balloon　was　to　suffice；　measuring　100　feet　in　diameter；　and　capable　of　raising　in　the　gross　30；000　lbs。　　To　manoeuvre　this　monstrous　engine　he　calculates　he　would　require　a　cable　five　miles　long；　by　means　of　which　he　hoped；　in　some　manner；　to　work　his　way　directly　over　the　fortress；　and　to　remain　poised　at　that　point　at　the　height　of　a　mile　in　the　sky。　　Once　granted　that　he　could　arrive　and　maintain　himself　at　that　position；　the　throwing　out　of　combustibles　would　be　simple；　though　even　then　the　spot　where　they　would　alight　after　the　drop　of　a　mile　would　be　by　no　means　certain。　　It　is　also　obvious　that　a　vast　amount　of　gas　would　have　to　be　sacrificed　to　compensate　for　the　prodigal　discharge　of　ballast　in　the　form　of　missiles。

The　idea　of　manoeuvring　a　balloon　in　a　wind；　and　poising　it　in　the　manner　suggested；　is；　of　course；　preposterous；　and　when　one　considers　the　attempt　to　aim　bombs　from　a　moving　balloon　high　in　air　the　case　becomes　yet　more　absurd。　　Any　such　missile　would　partake　of　the　motion　of　the　balloon　itself；　and　it　would　be　impossible　to　tell　where　it　would　strike　the　earth。

To　give　an　example　which　is　often　enough　tried　in　balloon　travel　when　the　ground　below　is　clear。　　A　glass　bottle　（presumably　empty）　is　cast　overboard　and　its　fall　watched。　　It　is　seen　not　to　be　left　behind；　but　to　keep　pace　with　the　balloon；　shrinking　gradually　to　an　object　　too　small　to　be　discerned；　except　when　every　now　and　then　a　ray　of　sunlight　reflected　off　it　reveals　it　for　a　moment　as　it　continues　to　plunge　downwards。　　After　a　very　few　seconds　the　impression　is　that　it　is　about　to　reach　the　earth；　and　the　eye　forms　a　guess　at　some　spot　which　it　will　strike；　but　the　spot　is　quickly　passed；　and　the　bottle　travels　far　beyond　across　a　field；　over　the　further　fence；　and　vastly　further　yet；　indeed；　inasmuch　as　to　fall　a　mile　in　air　a　heavy　body　may　take　over　twenty　secondsand　twenty　seconds　is　long　to　those　who　watchit　is　often　impossible　to　tell　to　two　or　three　fields　where　it　will　finally　settle。

All　this　while　the　risk　that　a　balloon　would　run　of　being　riddled　by　bullets；　shrapnel；　or　pom…poms　has　not　been　taken　into　account；　and　as　to　the　estimate　of　this　risk　there　is　some　difference　of　opinion。　　The　balloon　corps　and　the　artillery　apparently　approach　the　question　with　different　bias。　　On　the　one　hand；　it　is　stated　with　perfect　truth　that　a　free　balloon；　which　is　generally　either　rising　or　falling；　as　well　as　moving　across　country；　is　a　hard　object　to　hit；　and　a　marksman　would　only　strike　it　with　a　chance　or　blundering　shot；　but；　on　the　other　hand　let　us　take　the　following　report　of　three　years　ago。

The　German　artillery　had　been　testing　the　efficiency　of　a　quick…firing　gun　when　used　against　a　balloon；　and　they　decided　that　the　latter　would　have　no　chance　of　escape　except　at　night。　　A　German　kite…balloon　was　kept　moving　at　an　altitude　of　600　metres；　and　the　guns　trained　upon　it　were　distant　3；000　metres。　　It　was　then　stated　that　after　the　third　discharge　of　the　rapid　firing　battery　the　range　was　found；　when　all　was　at　once　over　with　the　balloon；　for；　not　only　was　it　hit　with　every　discharge；　but　it　was　presently　set　on　fire　and　annihilated。

But；　in　any　case；　the　antique　mode　of　keeping　a　balloon　moored　at　any　spot　as　a　post　of　observation　must　be　abandoned　in　modern　warfare。　　Major　Baden…Powell；　speaking　from　personal　experience　in　South　Africa；　has　shown　how　dangerous；　or　else　how　useless；　such　a　form　of　reconnaissance　has　become。　　〃I　remember；〃　he　says；　〃at　the　battle　of　Magersfontein　my　company　was　lying　down　in　extended　order　towards　the　left　of　our　line。　　We　were　perfectly　safe　from　musketry　fire；　as　we　lay；　perhaps；　two　miles　from　the　Boer　trenches；　which　were　being　shelled　by　some　of　our　guns　close　by。　　The　enemy's　artillery　was　practically　silent。　　Presently；　on　looking　round；　I　descried　our　balloon　away　out　behind　us　about　two　miles　off。　　Then　she　steadily　rose　and　made　several　trips　to　a　good　height；　but　what　could　be　seen　from　that　distance？　　When　a　large　number　of　our　troops　were　ranged　up　within　800　yards　of　the　trenches；　and　many　more　at　all　points　behind　them；　what　useful　information　could　be　obtained　by　means　of　the　balloon　four　miles　off？〃

The　same　eminent　authority　insists　on　the　necessity　of　an　observing　war　balloon　making　short　ascents。　　The　balloon；　in　his　opinion；　should　be　allowed　to　ascend　rapidly　to　its　full　height；　and　with　as　little　delay　as　possible　be　hauled　down　again。　　Under　these　conditions　it　may　then　be　well　worth　testing　whether　the　primitive　form　of　balloon；　the　Montgolfier；　might　not　be　the　most　valuable。　　Instead　of　being　made；　as　the　war　balloon　is　now；　of　fragile　material；　and　filled　with　costly　gas　difficult　to　procure；　and　which　has　to　be　conveyed　in　heavy　and　cumbersome　cylinders；　a　hot　air　balloon　could　be　rapidly　carried　by　hand　anywhere　where　a　few　men　could　push　their　way。　　It　is　of　strong　material；　readily　mended　if　torn；　and　could　be　inflated　for　short　ascents；　if　not　by　mere　brush　wood；　then　by　a　portable　blast　furnace　and　petroleum。

But　there　is　a　further　use　for　balloons　in　warfare　not　yet　exploited。　　The　Siege　of　Paris　showed　the　utility　of　free　balloons；　and　occasions　arise　when　their　use　might　be　still　further　extended。　　The　writer　pointed　out　that　it　might　have　been　very　possible　for　an　aeronaut　of　experience；　by　choosing　the　right　weather　and　the　right　position　along　the　British　lines；　to　have　skilfully　manoeuvred　a　free　balloon　by　means　of　upper　currents；　so　as　to　convey　all…important　intelligence　to　besieged　Mafeking；　and　he　proved　that　it　would　have　sufficed　if　the　balloon　could　have　been　〃tacked〃　across　the　sky　to　within　some　fifteen　miles　of　the　desired　goal。

The　mode　of　signalling　which　he　proposed　was　by　means　of　a　〃collapsing　drum；〃　an　instrument　of　occasional　use　in　the　Navy。　　A　modification　of　this　instrument；　as　employed　by　the　writer；　consisted　of　a　light；　spherical；　drum…shaped　frame　of　large　size；　which；　when　covered　with　dark　material　and　hung　in　the　clear　below　the　car　of　a　lofty　balloon；　could　be　well　seen　either　against　blue　sky　or　grey　at　a　great　distance。　　The　so…called　drum　could；　by　a　very　simple　contrivance；　readily　worked　from　the　car；　be　made　to　collapse　into　a　very　inconspicuous　object；　and　thus　be　capable　of　displaying　Morse　Code　signals。　　A　long　pause　with　the　drum　extendedlike　the　long　wave　of　a　signalling　flagwould　denote　a　〃dash；〃　and　a　short　pause　a　〃dot；〃　and　these　motions　would　be　at　once　intelligible　to　anyone　acquainted　with　the　now　universal　Morse　Code　system。

Provided　with　an　apparatus　of　the　kind；　the　writer　made　an　ascent　from　Newbury　at　a　time　when　the　military　camps　were　lying　on　Salisbury　Plain　at　a　distance　of　nearly　twenty　miles　to　the　south…west。　　The　ground　wind　up　to　2；500　feet　on　starting　was　nearly　due　north；　and　would　have　defeated　the　attempt；　again；　the　air　stream　blowing　above　that　height　was　nearly　due　east；　which　again　would　have　proved　unsuitable。　　But　it　was　manifestly　possible　to　utilise　the　two　currents；　and　with　good　luck　to　zig…zag　one's　course　so　as　to　come　within　easy　signalling　distance　of　the　various　camps；　and；　as　a　matter　of　fact；　we　actually　passed　immediately　over　Bulford　Camp；　with　which　we　exchanged　signals；　while　two　other　camps　lay　close　to　right　and　left　of　us。　　Fortune　favouring　us；　we　had　actually　hit　our　mark；　though　it　would　have　been　sufficient　for　the　experiment　had　our　course　lain　within　ten　miles　right　or　left。

Yet　a　further　use　for　the　balloon　in　warfare　remains　untried　in　this　country。　　Acting　under　the　advice　of　experts　in　the　Service；　the　writer；　in　the　early　part　of　the　present　year；　suggested　to　the　Admiralty　the　desirabilit