aeroplanes and dirigibles of war-第20节

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determine　their　significance。　　It　is　for　this　reason　that　no

lights　of　any　description　are　permitted　in　the　advance　trenches。　

The　striking　of　a　match　may　easily　betray　a　position　to　the　alert

eye　above。



So　far　as　the　British　Army　is　concerned　a　complete　code　is　in

operation　for　communicating　between　aeroplanes　and　the　ground　at

night。　　Very's　lights　are　used　for　this　purpose；　it　being

possible　to　distinguish　the　respective　colours　at　a　distance　of

six　miles　and　from　an　altitude　of　2；000　feet。　　The　lights　are

used　both　by　the　aeroplane　and　the　battery　of　artillery。



The　code　is　varied　frequently；　but　the　following　conveys　a　rough

idea　of　how　communication　is　carried　out　by　this　means　under

cover　of　darkness。　　The　aeroplane　has　located　its　objective　and

has　returned　to　the　pre…arranged　altitude。　　A　red　light　is　thrown

by　the　airman。　　It　indicates　that　he　is　directly　over　the　enemy's

position。　　A　similarly　coloured　light　is　shown　by　the　artillery

officer；　which　intimates　to　the　airman　that　his　signal　has　been

observed　and　that　the　range　has　been　taken。



In　observing　the　effects　of　artillery　fire　a　code　of　signals　is

employed　between　the　airman　and　the　artillery　officer　to　indicate

whether　the　shot　is　〃long〃　or　〃short；〃　to　the　right　or　to　the

left　of　the　mark；　while　others　intimate　whether　the　fuse　is

correctly　timed　or　otherwise。　　It　is　necessary　to　change　the　code

fairly　frequently；　not　only　lest　it　should　fall　into　the　enemy's

hands；　but　also　to　baffle　the　hostile　forces；　otherwise；　after　a

little　experience；　the　latter　would　be　able　to　divine　the

significance　of　the　signals；　and；　in　anticipation　of　being

greeted　with　a　warm　fusillade；　would　complete　hurried

arrangements　to　mitigate　its　effects；　if　not　to　vacate　the

position　until　the　bombardment　had　ceased。



Sufficient　experience　has　already　been　gathered；　however；　to

prove　the　salient　fact　that　the　airman　is　destined　to　play　an

important　part　in　the　direction　and　control　of　artillery…fire。　

Already　he　has　been　responsible　for　a　re…arrangement　of　strategy

and　tactics。　　The　man　aloft　holds　such　a　superior　position　as　to

defy　subjugation；　the　alternative　is　to　render　his　work　more

difficult；　if　not　absolutely　impossible。







CHAPTER　X

BOMB…THROWING　FROM　AIR…CRAFT



During　the　piping　times　of　peace　the　utility　of　aircraft　as

weapons　of　offence　was　discussed　freely　in　an　academic　manner。　

It　was　urged　that　the　usefulness　of　such　vessels　in　this

particular　field　would　be　restricted　to　bomb…throwing。　　So　far

these　contentions　have　been　substantiated　during　the　present

campaign。　　At　the　same　time　it　was　averred　that　even　as　a

bomb…thrower　the　ship　of　the　air　would　prove　an　uncertain

quantity；　and　that　the　results　achieved　would　be　quite　contrary

to　expectations。　　Here　again　theory　has　been　supported　by

practice；　inasmuch　as　the　damage　wrought　by　bombs　has　been

comparatively　insignificant。



The　Zeppelin　raids　upon　Antwerp　and　Britain　were　a　fiasco　in　the

military　sense。　　The　damage　inflicted　by　the　bombs　was　not　at　all

in　proportion　to　the　quantity　of　explosive　used。　　True；　in　the

case　of　Antwerp；　it　demoralised　the　civilian　population　somewhat

effectively；　which　perhaps　was　the　desired　end；　but　the　military

results　were　nil。



The　Zeppelin；　and　indeed　all　dirigibles　of　large　size；　have　one

advantage　over　aeroplanes。　　They　are　able　to　throw　bombs　of

larger　size　and　charged　with　greater　quantities　of　high　explosive

and　shrapnel　than　those　which　can　be　hurled　from　heavier…than…air

machines。　　Thus　it　has　been　stated　that　the　largest　Zeppelins　can

drop　single　charges　exceeding　one　ton　in　weight；　but　such　a

statement　is　not　to　be　credited。



The　shell　generally　used　by　the　Zeppelin　measures　about　47　inches

in　length　by　8　1/2　inches　in　diameter；　and　varies　in　weight　from

200　to　242　pounds。　　Where　destruction　pure　and　simple　is　desired；

the　shell　is　charged　with　a　high　explosive　such　as　picric　acid　or

T。N。T。；　the　colloquial　abbreviation　for　the　devastating　agent

scientifically　known　as　〃Trinitrotoluene；〃　the　base　of　which；　in

common　with　all　the　high　explosives　used　by　the　different　powers

and　variously　known　as　lyddite；　melinite；　cheddite；　and　so　forth；

is　picric　acid。　　Such　a　bomb；　if　it　strikes　the　objective；　a

building；　for　instance；　fairly　and　squarely；　may　inflict

widespread　material　damage。



On　the　other　hand；　where　it　is　desired　to　scatter　death；　as　well

as　destruction；　far　and　wide；　an　elaborate　form　of　shrapnel　shell

is　utilised。　　The　shell　in　addition　to　a　bursting　charge；

contains　bullets；　pieces　of　iron；　and　other　metallic　fragments。

When　the　shell　bursts；　their　contents；　together　with　the　pieces

of　the　shell　which　is　likewise　broken　up　by　the　explosion；　are

hurled　in　all　directions　over　a　radius　of　some　50　yards　or　more；

according　to　the　bursting　charge。



These　shells　are　fired　upon　impact；　a　detonator　exploding　the

main　charge。　　The　detonator；　comprising　fulminate　of　mercury；　is

placed　in　the　head　or　tail　of　the　missile。　　To　secure　perfect

detonation　and　to　distribute　the　death…dealing　contents　evenly　in

all　directions；　it　is　essential　that　the　bomb　should　strike　the

ground　almost　at　right　angles：　otherwise　the　contents　are　hurled

irregularly　and　perhaps　in　one　direction　only。　　One　great

objection　to　the　percussion　system；　as　the　method　of　impact

detonation　is　called；　is　that　the　damage　may　be　localised。　　A

bomb　launched　from　a　height　of　say　1；000　feet　attains　terrific

velocity；　due　to　the　force　of　gravity　in　conjunction　with　its　own

weight；　in　consonance　with　the　law　concerning　a　falling　body；　by

the　time　it　reaches　the　ground。　　It　buries　itself　to　a　certain

depth　before　bursting　so　that　the　forces　of　the　explosion　become

somewhat　muffled　as　it　were。　　A　huge　deep　holea　miniature

volcano　crateris　formed；　while　all　the　glass　in　the　immediate

vicinity　of　the　explosion　may　be　shattered　by　the　concussion；　and

the　walls　of　adjacent　buildings　be　bespattered　with　shrapnel。



Although　it　is　stated　that　an　airship　is　able　to　drop　a　single

missile　weighing　one　ton　in　weight；　there　has　been　no　attempt　to

prove　the　contention　by　practice。　　In　all　probability　the

heaviest　shell　launched　from　a　Zeppelin　has　not　exceeded　300

pounds。　　There　is　one　cogent　reason　for　such　a　belief。　　A　bomb

weighing　one　ton　is　equivalent　to　a　similar　weight　of　ballast。　

If　this　were　discarded　suddenly　the　equilibrium　of　the　dirigible　

would　be　seriously　disturbedit　would　exert　a　tendency　to　fly

upwards　at　a　rapid　speed。　　It　is　doubtful　whether　the　planes

controlling　movement　in　the　vertical　plane　would　ever　be　able　to

counteract　this　enormous　vertical　thrust。　　Something　would　have

to　submit　to　the　strain。　　Even　if　the　dirigible　displaced　say　20

tons；　and　a　bomb　weighing　one　ton　were　discharged；　the　weight　of

the　balloon　would　be　decreased　suddenly　by　approximately　five　

per　cent；　so　that　it　would　shoot　upwards　at　an　alarming　speed；

and　some　seconds　would　elapse　before　control　was　regained。



The　method　of　launching　bombs　from　airships　varies　considerably。　

Some　are　released　from　a　cradle；　being　tilted　into　position　ready

for　firing；　while　others　are　discharged　from　a　tube　somewhat

reminiscent　of　that　used　for　firing　torpedoes；　with　the　exception

that　little　or　no　initial　impetus　is　imparted　to　the　missile；　the

velocity　it　attains　is　essentially　gravitational。



The　French　favour　the　tube…launching　method　since　thereby　it　is

stated　to　be　possible　to　take　more　accurate　aim。　　The　objective

is　sighted　and　the　bomb　launched　at　the　critical　moment。　　In　some　

instances　the　French　employ　an　automatic　detonator　which

corresponds　in　a　certain　measure　to　the　time…fuse　of　a　shrapnel

shell　fired　from　a　gun。



The　bomb…thrower　reads　the　altitude　of　his　airship　as　indicated

by　his　barometer　or　other　recording　instrument；　and　by　means　of　a

table　at　his　command　ascertains　in　a　moment　the　time　which　will

elapse　before　the　bomb　strikes　the　ground。　　The　automatic

detonator　is　set　in　motion　and　the　bomb　released　to　explode

approximately　at　the　height　to　which　it　is　set。　　When　it　bursts

the　full　force　of　the　explosion　is　distributed　downwards　and

laterally。　　Owing　to　the　difficulty　of　ensuring　the　explosion　of

the　bomb　at　the　exact　height　desired；　it　is　also　made　to　explode

upon　impact　so　as　to　make　doubly　sure　of　its　efficacy。



Firing　timed　bombs　from　aloft；　however；　is　not　free　from

excitement　and　danger；　as　the　experience　of　a　French　airman

demonstrates。　　His　dirigible　had　been　commanded　to　make　a

night…raid　upon　a　railway　station　which　was　a　strategical

junction　for　the　movement　of　the　enemy's　troops。　　Although　the

hostile　searchlights　were　active；　the　airship　contrived　to　slip

between　the　spokes　of　light　without　being　observed。　　By

descending　to　a　comparatively　low　altitude　the　pilot　was　able　to

pick　up　the　objective。



Three　projectiles　were　discharged　in