aeroplanes and dirigibles of war-第34节

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！
————未阅读完？加入书签已便下次继续阅读！



feet；　or　on　speed　combined　with　rapid　twisting　and　turning；　or

erratic　undulating　flight；　rendering　it　extremely　difficult　for

the　gun…layer　to　follow　his　path　with　sufficient　celerity　to

ensure　accurate　firing。



At　altitudes　ranging　between　4；000　and　6；000　feet　the　aeroplane

comes　within　the　range　of　rifle　and　machine…gun　firing。　　The

former；　however；　unless　discharged　in　volleys　with　the　shots

covering　a　wide　area；　is　not　particularly　dangerous；　inasmuch　as

the　odds　are　overwhelmingly　against　the　rifleman。　　He　is　not

accustomed　to　following　and　firing　upon　a　rapidly　moving

objective；　the　result　being　that　ninety…nine　times　out　of　a

hundred　he　fails　to　register　a　hit。　　On　the　other　hand　the

advantage　accruing　from　machine…gun　fire　is；　that　owing　to　the

continuous　stream　of　bullets　projected；　there　is　a　greater

possibility　of　the　gun　being　trained　upon　the　objective　and

putting　it　hors　de　combat。



But；　taking　all　things　into　consideration；　and　notwithstanding

the　achievements　of　the　artillerist；　the　advantages　are

overwhelmingly　on　the　side　of　the　aviator。　　When　one　reflects

upon　the　total　sum　of　aircraft　which　have　been　brought　to　earth

during　the　present　campaign；　it　will　be　realised　that　the　number

of　prizes　is　insignificant　in　comparison　with　the　quantity　of

ammunition　expended。







CHAPTER　XVI

MINING　THE　AIR



While　the　anti…aircraft　gun　represents　the　only　force　which　has

been　brought　to　the　practical　stage　for　repelling　aerial　attack；

and　incidentally　is　the　sole　offensive　weapon　which　has

established　its　effectiveness；　many　other　schemes　have　been

devised　and　suggested　to　consummate　these　ends。　　While　some　of

these　schemes　are　wildly　fantastic；　others　are　feasible　within

certain　limitations；　as　for　instance　when　directed　against

dirigibles。



It　has　been　argued　that　the　atmosphere　is　akin　to　the　salt　seas；

that　an　aerial　vessel　in　its　particular　element　is　confronted

with　dangers　identical　with　those　prevailing　among　the　waters　of

the　earth。　　But　such　an　analogy　is　fallacious：　there　is　no　more

similarity　between　the　air　and　the　ocean　than　there　is　between　an

airship　and　a　man…of…war。　　The　waters　of　the　earth　conceal　from

sight　innumerable　obstructions；　such　as　rocks；　shoals；　sandbanks；

and　other　dangers　which　cannot　by　any　means　be　readily　detected。



But　no　such　impediments　are　encountered　in　the　ether。　　The　craft

of　the　air　is　virtually　a　free　age　in　the　three　dimensions。　　It

can　go　whither　it　will　without　let　or　hindrance　so　long　as　the

mechanical　agencies　of　man　are　able　to　cope　with　the　influences

of　Nature。　　It　can　ascend　to　a　height　which　is　out　of　all

proportion　to　the　depth　to　which　the　submarine　can　descend　in

safety。　　It　is　a　matter　of　current　knowledge　that　a　submarine

cannot　sink　to　a　depth　of　more　than　250　feet：　an　aerial　vessel　is

able　to　ascend　to　5；000；　8；000；　or　even　10；000　feet　above　the

earth；　and　the　higher　the　altitude　it　attains　the　greater　is　its

degree　of　safety。　　The　limit　of　ascension　is　governed　merely　by

the　physical　capacities　of　those　who　are　responsible　for　the

aerial　vessel's　movement。



It　is　for　this　reason　that　the　defensive　measures　which　are

practised　in　the　waters　of　the　earth　are　inapplicable　to　the

atmosphere。　　Movement　by；　or　in；　water　is　governed　by　the　depth

of　channels；　and　these　may　be　rendered　impassable　or　dangerous　to

negotiate　by　the　planting　of　mines。　　A　passing　ship　or　submarine

may　circumvent　these　explosive　obstructions；　but　such　a

successful　manoeuvre　is　generally　a　matter　of　good　luck。　　So　far

as　submarines　are　concerned　the　fact　must　not　be　over　looked　that

movements　in　the　sea　are　carried　out　under　blind　conditions：　the

navigator　is　unable　to　see　where　he　is　going；　the　optic　faculty

is　rendered　nugatory。　　Contrast　the　disability　of　the　submarine

with　the　privileges　of　its　consort　in　the　air。　　The　latter　is

able　to　profit　from　vision。　　The　aerial　navigator　is　able　to　see

every　inch　of　his　way；　at　least　during　daylight。　　When　darkness

falls　he　is　condemned　to　the　same　helplessness　as　his　confrere　in

the　waters　below。



A　well…known　British　authority　upon　aviation　suggested　that

advantage　should　be　taken　of　this　disability；　and　that　the　air

should　be　mined　during　periods　of　darkness　and　fog　to　secure

protection　against　aerial　invasion。　　At　first　sight　the　proposal

appears　to　be　absolutely　grotesque；　but　a　little　reflection　will

suffice　to　demonstrate　its　possibilities　when　the　area　to　be

defended　is　comparatively　limited。　　The　suggestion　merely

proposes　to　profit　from　one　defect　of　the　dirigible。　　The　latter；

when　bent　upon　a　daring　expedition；　naturally　prefers　to　make　a

bee…line　towards　its　objective：　fuel　considerations　as　a　matter

of　fact　compel　it　to　do　so。　　Consequently　it　is　possible；　within

certain　limits；　to　anticipate　the　route　which　an　invading　craft　

will　follow：　the　course　is　practically　as　obvious　as　if　the

vessel　were　condemned　to　a　narrow　lane　marked　out　by　sign…posts。

Moreover；　if　approaching　under　cover　of　night　or　during　thick

weather；　it　will　metaphorically　〃hug　the　ground。〃　To　attempt　to　

complete　its　task　at　a　great　height　is　to　court　failure；　as　the

range　of　vision　is　necessarily　so　limited。



Under　these　circumstances　the　mining　of　the　air　could　be　carried

out　upon　the　obvious　approaches　to　a　threatened　area。　　The　mines；

comprising　large　charges　of　high…explosive　and　combustible

material；　would　be　attached　to　small　captive　balloons　similar　to

the　〃sounding　balloons〃　which　are　so　much　used　by　meteorologists

in　operations　for　sounding　the　upper　strata　of　the　atmosphere。　　

These　pilot　balloons　would　be　captive；　their　thin　wires　being

wound　upon　winches　planted　at　close　intervals　along　the

coast…line。　　The　balloon…mines　themselves　would　be　sent　to

varying　heights；　ranging　from　1；000　to　5；000　feet；　and　with

several　attached　to　each　cable；　the　disposition　of　the　mines

in　the　air　in　such　an　irregular　manner　being　in　fact　closely

similar　to　the　practice　adopted　in　the　mining　of　a　channel　for

protection　against　submarines　and　hostile　ships。



The　suggestion　is　that　these　mines　should　be　sent　aloft　at　dusk

or　upon　the　approach　of　thick　and　foggy　weather；　and　should　be

wound　in　at　dawn　or　when　the　atmosphere　cleared；　inasmuch　as　in

fine　weather　the　floating　aerial　menace　would　be　readily　detected

by　the　pilot　of　a　dirigible；　and　would　be　carefully　avoided。　　If

the　network　were　sufficiently　intricate　it　would　not　be　easy　for

an　airship　travelling　at　night　or　in　foggy　weather　to　steer　clear

of　danger；　for　the　wires　holding　the　balloons　captive　would　be

difficult　to　distinguish。



The　mines　would　depend　upon　detonators　to　complete　their　work；

and　here　again　they　would　bear　a　close　resemblance　to　sea…mines。

By　looping　the　mines　their　deadliness　could　be　increased。　　The

unsuspicious　airship；　advancing　under　cover　of　darkness　or　thick

weather；　might　foul　one　of　the　wires；　and；　driving　forward；　would

tend　to　pull　one　or　more　mines　against　itself。　　Under　the　force

of　the　impact；　no　matter　how　gentle；　or　slight；　one　or　more　of

the　detonating　levers　would　be　moved；　causing　the　mine　to

explode；　thus　bursting　the　lifting　bag　of　the　vessel；　and　firing

its　gaseous　contents。　　An　alternative　method；　especially　when　a

cable　carried　only　a　single　mine；　would　be　to　wind　in　the　captive

balloon　directly　the　wire　was　fouled　by　an　invading　aerial　craft；

the　process　being　continued　until　the　mine　was　brought　against

the　vessel　and　thereby　detonated。



Another　proposed　mining　method　differs　materially　in　its

application。　　In　this　instance　it　is　suggested　that　the　mines

should　be　sent　aloft；　but　should　not　be　of　the　contact　type；　and

should　not　be　fired　by　impact　detonators；　but　that　dependence

should　be　placed　rather　upon　the　disturbing　forces　of　a　severe

concussion　in　the　air。　　The　mines　would　be　floating　aoft；　and

the　advance　of　the　airship　would　be　detected。　　The　elevation

of　the　mines　in　the　vicinity　of　the　invading　craft　would　be

known；　while　the　altitude　of　the　airship　in　relation　thereto

could　be　calculated。　　Then；　it　is　proposed　that　a　mine　within　d

certain　radius　of　the　approaching　craft；　and；　of　course；　below

it；　should　be　fired　electrically　from　the　ground。　　It　is

maintained　that　if　the　charge　were　sufficiently　heavy　and　an

adequate　sheet　of　flame　were　produced　as　a　result　of　the

ignition；　an　airship　within　a　hundred　yards　thereof　would　be

imperilled　seriously；　while　the　other　mines　would　also　be　fired；

communicating　ignition　from　one　to　the　other。　　The　equilibrium

of　the　airship　is　so　delicate　that　it　can　be　readily　upset；　and

taking　into　account　the　facts　that　gas　is　always　exuding　from

the　bag；　and　that　hydrogen　has　a　tendency　to　spread　somewhat　in

the　manner　of　oil　upon　water；　it　is　argued　that　the　gas　would　be

ignited；　and　would　bring　about　the　explosion　of　the　airship。



Another　method　has　even　been　advo