aeroplanes and dirigibles of war-第34部分

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or　zone　comprises　merely　two　or　three　successive　stretches　of

trenches　and　other　defences；　representing　a　belt　five　miles　or　so

in　width；　but　this　is　a　fallacy。　　The　fighting　zone　is　at　least

20　miles　in　width；　that　is　to　say；　the　occupied　territory　in

which　vital　movements　take　place　represents　a　distance　of　20

miles　from　the　foremost　line　of　trenches　to　the　extreme　rear；

and　then　comes　the　secondary　zone；　which　may　be　a　further　10

miles　or　more　in　depth。　　Consequently　the　airman　must　fly　at

least　30　miles　in　a　bee…line　to　cover　the　transverse　belt　of　the

enemy's　field　of　operations。　　Upon　the　German　and　Russian　sides

this　zone　is　of　far　greater　depth；　ranging　up　to　50　miles　or　so


in　width。　　In　these　circumstances　the　difficulties　of　ethereal

communication　'twixt　air　and　earth　may　be　realised　under　the

present　limitations　of　radius　from　which　it　is　possible　to

transmit。



But　there　are　reasons　still　more　cogent　to　explain　why　wireless

telegraphy　has　not　been　used　upon　a　more　extensive　scale　during

the　present　campaign。　　Wireless　communication　is　not　secretive。　　

In　other　words；　its　messages　may　be　picked　up　by　friend　and　foe

alike　with　equal　facility。　　True；　the　messages　are　sent　in　code；

which　may　be　unintelligible　to　the　enemy。　　In　this　event　the

opponent　endeavours　to　render　the　communications　undecipherable

to　one　and　all　by　what　is　known　as　〃jambing。〃　That　is　to　say；　he

sends　out　an　aimless　string　of　signals　for　the　purpose　of

confusing　senders　and　receivers；　and　this　is　continued　without

cessation　and　at　a　rapid　rate。　　The　result　is　that　messages

become　blurred　and　undecipherable。



But　there　is　another　danger　attending　the　use　of　wireless　upon

the　battlefield。　　The　fact　that　the　stations　are　of　limited　range

is　well　known　to　the　opposing　forces；　and　they　are　equally　well

aware　of　the　fact　that　aerial　craft　cannot　communicate　over　long

distances。　　For　instance；　A　sends　his　airmen　aloft　and

conversation　begins　between　the　clouds　and　the　ground。　　Presently

the　receivers　of　B　begin　to　record　faint　signals。　　They　fluctuate

in　intensity；　but　within　a　few　seconds　B　gathers　that　an

aeroplane　is　aloft　and　communicating　with　its　base。　　By　the　aid

of　the　field　telephone　B　gets　into　touch　with　his　whole　string　of

wireless　stations　and　orders　a　keen　look…out　and　a　listening　ear

to　ascertain　whether　they　have　heard　the　same　signals。　　Some

report　that　the　signals　are　quite　distinct　and　growing　louder；

while　others　declare　that　the　signals　are　growing　fainter　and

intermittent。　　In　this　manner　B　is　able　to　deduce　in　which

direction　the　aeroplane　is　flying。　　Thus　if　those　to　the　east

report　that　signals　are　growing　stronger；　while　the　stations　on

the　west　state　that　they　are　diminishing；　it　is　obvious　that　the

aeroplane　is　flying　west　to　east；　and　vice　versa　when　the　west

hears　more　plainly　at　the　expense　of　the　east。　　If；　however；　both

should　report　that　signals　are　growing　stronger；　then　it　is

obvious　that　the　aircraft　is　advancing　directly　towards　them。



It　was　this　ability　to　deduce　direction　from　the　sound　of　the

signals　which　led　to　the　location　of　the　Zeppelin　which　came　down

at　Lun6ville　some　months　previous　to　the　war；　and　which

threatened　to　develop　into　a　diplomatic　incident　of　serious

importance。　　The　French　wireless　stations　running　south…east　to

north…west　were　vigilant；　and　the　outer　station　on　the　north…west

side　picked　up　the　Zeppelin's　conversation。　　It　maintained　a

discreet　silence；　but　communicated　by　telephone　to　its　colleagues

behind。



Presently　No。　2　station　came　within　range；　followed　by　Nos。　3；　4；

5；　6；　and　so　on　in　turn。　　Thus　the　track　of　the　Zeppelin　was

dogged　silently　through　the　air　by　its　wireless　conversation　as

easily　and　as　positively　as　if　its　flight　had　been　followed　by

the　naked　eye。　　The　Zeppelin　travellers　were　quite　ignorant　of

this　action　upon　the　part　of　the　French　and　were　surprised　when

they　were　rounded…up　to　learn　that　they　had　been　tracked　so

ruthlessly。　　Every　message　which　the　wireless　of　the　Zeppelin　had

transmitted　had　been　received　and　filed　by　the　French。



Under　these　circumstances　it　is　doubtful　whether　wireless

telegraphy　between　aircraft　and　the　forces　beneath　will　be

adopted　extensively　during　the　present　campaign。　　Of　course；

should　some　radical　improvement　be　perfected；　whereby

communication　may　be　rendered　absolutely　secretive；　while　no

intimation　is　conveyed　to　the　enemy　that　ethereal　conversation　is

in　progress；　then　the　whole　situation　will　be　changed；　and　there

may　be　remarkable　developments。







CHAPTER　XVIII

AIRCRAFT　AND　NAVAL　OPERATIONS



When　once　the　flying　machine　had　indicated　its　possibilities　in

connection　with　land　operations　it　was　only　natural　that

endeavours　should　be　made　to　adapt　it　to　the　more　rigorous

requirements　of　the　naval　service。　　But　the　conditions　are　so

vastly　dissimilar　that　only　a　meagre　measure　of　success　has　been

recorded。　　Bomb…throwing　from　aloft　upon　the　decks　of　battleships

appeals　vividly　to　the　popular　imagination；　and　the　widespread

destruction　which　may　be　caused　by　dropping　such　an　agent　down

the　funnel　of　a　vessel　into　the　boiler…room　is　a　favourite　theme

among　writers　of　fiction　and　artists。　　But　hitting　such　an

objective　while　it　is　tearing　at　high　speed　through　the　water；

from　a　height　of　several　thousand　feet　is　a　vastly　different　task

from　throwing　sticks　and　balls　at　an　Aunt　Sally　on　terra　firma：

the　target　is　so　small　and　elusive。



Practically　it　is　impossible　to　employ　the　flying　machine；

whether　it　be　a　dirigible　or　an　aeroplane；　in　this　field。　　Many

factors　militate　against　such　an　application。　　In　the　first　place

there　is　a　very　wide　difference　between　dry　land　and　a　stretch　of

water　as　an　area　over　which　to　manoeuvre。　　So　far　as　the　land　is

concerned　descent　is　practicable　at　any　time　and　almost　anywhere。

But　an　attempt　to　descend　upon　the　open　sea　even　when　the　latter

is　as　calm　as　the　proverbial　mill…pond　is　fraught　with

considerable　danger。　　The　air…currents　immediately　above　the

water　differ　radically　from　those　prevailing　above　the　surface　of

the　land。　　Solar　radiation　also　plays　a　very　vital　part。　　In　fact

the　dirigible　dare　not　venture　to　make　such　a　landing　even　if　it

be　provided　with　floats。　　The　chances　are　a　thousand　to　one　that

the　cars　will　become　water…logged；　rendering　re…ascent　a　matter

of　extreme　difficulty；　if　not　absolutely　impossible。　　On　the

other　hand；　the　aeroplane　when　equipped　with　floats；　is　able　to

alight　upon　the　water；　and　to　rest　thereon　for　a　time。　　It　may

even　take　in　a　new　supply　of　fuel　if　the　elements　be　propitious；

and　may　be　able　to　re…ascend；　but　the　occasions　are　rare　when

such　operations　can　be　carried　out　successfully。



In　operations　over　water　the　airman　is　confronted　with　one

serious　dangerthe　risk　of　losing　his　bearings　and　his　way。　　For

instance；　many　attempts　have　been　made　to　cross　the　North　Sea　by

aeroplane；　but　only　one　has　proved　successful　so　far。　　The

intrepid　aviator　did　succeed　in　passing　from　the　shore　of　Britain

to　the　coast　of　Scandinavia。　　Many　people　suppose　that　because　an

airman　is　equipped　with　a　compass　he　must　be　able　to　find　his

way；　but　this　is　a　fallacy。　　The　aviator　is　in　the　same　plight　as

a　mariner　who　is　compelled　from　circumstances　to　rely　upon　his

compass　alone；　and　who　is　debarred　by　inclement　weather　from

deciding　his　precise　position　by　taking　the　sun。　　A　ship

ploughing　the　waters　has　to　contend　against　the　action　of　cross

currents；　the　speed　of　which　varies　considerably；　as　well　as

adverse　winds。　　Unless　absolute　correction　for　these　influences

can　be　made　the　ship　will　wander　considerably　from　its　course。　　

The　airman　is　placed　in　a　worse　position。　　He　has　no　means　of

determining　the　direction　and　velocity　of　the　currents　prevailing

in　the　atmosphere；　and　his　compass　cannot　give　him　any　help　in

this　connection；　because　it　merely　indicates　direction。



Unless　the　airman　has　some　means　of　determining　his　position；

such　as　landmarks；　he　fails　to　realise　the　fact　that　he　is

drifting；　or；　even　if　he　becomes　aware　of　this　fact；　it　is　by　no

means　a　simple　straightforward　matter　for　him　to　make　adequate

allowance　for　the　factor。　　Side…drift　is　the　aviator's　greatest

enemy。　　It　cannot　be　determined　with　any　degree　of　accuracy。　　If

the　compass　were　an　infallible　guide　the　airman　would　be　able　to

complete　a　given　journey　in　dense　fog　just　as　easily　as　in　clear

weather。　　It　is　the　action　of　the　cross　currents　and　the

unconscious　drift　which　render　movement　in　the　air　during　fog　as

impracticable　with　safety　as　manoeuvring　through　the　water　under

similar　conditions。　　More　than　one　bold　and　skilful　aviator　has

essayed　the　crossing　of　the　English　Channel　and；　being　overtaken

by　fog；　has　failed　to　make　the　opposite　coast。　　His　compass　has

given　him　the　proper　direction；　but　the　side…drift　has　proved　his

undoing；　with　the　result　that　he　has　missed　his　objective。



The　fickle　character　of　the　winds　over　the　water；　especially　over

such　expanses　as　the　North　Sea；　constitutes　another　and　seriously

adverse　factor。　　Storms；　squalls；　gales；　and；　in　winter；

blizzards；　spring　up　with　magical　suddenness；　and　are　so　severe

that　no　aircraft　could　hope　to　live　in　them。　　But　such

visitations　are　more　to　be　dreaded　by　the　lighter…than…air　than

by　the　heavier…than…air　machines。　　The　former　offers　a

considerable　area　of　resistance　to　the　tempest　and　is　caught　up

by　the　whirlwind　before　the　pilot　fully　grasps　the　significant

chance　of　the　natural　phenomenon。　　Once　a　dirigible　is　swept　out

of　the　hands　of　its　pilot　its　doom　is　sealed。



On　the　other　hand；　the　speed　attainable　by　the　aeroplane

constitutes　its　safety。　　It　can　run　before　the　wind；　and　meantime

can　climb　steadily　and　rapidly　to　a　higher　altitude；　until　at

last　it　enters　a　contrary　wind　or　even　a　tolerably　quiescent

atmosph