aeroplanes and dirigibles of war- 第3部分

spring　up　suddenly。　　Consequently　a　second　method　is　practised。　　

This　is　to　dig　a　pit　into　the　ground　of　sufficient　size　to

receive　the　balloon。　　When　the　latter　is　hauled　in　it　is　lowered

into　this　pit　and　there　pegged　down　and　anchored。　　Thus　it　is

perfectly　safe　during　the　roughest　weather；　as　none　of　its　bulk

is　exposed　above　the　ground　level。　　Furthermore　it　is　not　a

conspicuous　object　for　the　concentration　of　hostile　fire。



In　some　instances；　and　where　the　military　department　is　possessed

of　an　elaborate　equipment　such　as　characterises　the　German　army；

when　reconnaissance　is　completed　and　the　balloon　is　to　be　removed

to　another　point；　the　gas　is　pumped　back　into　the　cylinders　for

further　use。　　Such　an　economical　proceeding　is　pretty　and　well

adapted　to　manoeuvres；　but　it　is　scarcely　feasible　in　actual

warfare；　for　the　simple　reason　that　the　pumping　takes　time。

Consequently　the　general　procedure；　when　the　balloon　has

completed　its　work；　is　to　permit　the　gas　to　escape　into　the　air

in　the　usual　manner；　and　to　draw　a　fresh　supply　of　gas　from

further　cylinders　when　the　occasion　arises　for　re…inflation。



Although　the　familiar　spherical　balloon　has　proved　perfectly

adequate　for　reconnoitring　in　the　British　and　French　armies；　the

German　authorities　maintained　that　it　was　not　satisfactory　in

anything　but　calm　weather。　　Accordingly　scientific　initiative　was

stimulated　with　a　view　to　the　evolution　of　a　superior　vessel。　　

These　endeavours　culminated　in　the　Parseval…Siegsfeld　captive

balloon；　which　has　a　quaint　appearance。　　It　has　the　form　of　a

bulky　cylinder　with　hemispherical　extremities。　　At　one　end　of　the

balloon　there　is　a　surrounding　outer　bag；　reminiscent　of　a

cancerous　growth。　　The　lower　end　of　this　is　open。　　This

attachment　serves　the　purpose　of　a　ballonet。　　The　wind　blowing

against　the　opening；　which　faces　it；　charges　the　ballonet　with

air。　　This　action；　it　is　claimed；　serves　to　steady　the　main

vessel；　somewhat　in　the　manner　of　the　tail　of　a　kite；　thereby

enabling　observations　to　be　made　as　easily　and　correctly　in　rough

as　in　calm　weather。　　The　appearance　of　the　balloon　while　aloft　is

certainly　curious。　　It　appears　to　be　rearing　up　on　end；　as　if　the

extremity　saddled　with　the　ballonet　were　weighted。



British　and　French　captive　balloon　authorities　are　disposed　to

discount　the　steadying　effect　of　this　attachment；　and；　indeed；　to

maintain　that　it　is　a　distinct　disadvantage。　　It　may　hold　the

vessel　steadier　for　the　purpose　of　observation；　but　at　the　same

time　it　renders　the　balloon　a　steadier　target　for　hostile　fire。　　

On　the　other　hand；　the　swaying　of　a　spherical　balloon　with　the

wind　materially　contributes　to　its　safety。　　A　moving　object；

particularly　when　its　oscillations　are　irregular　and

incalculable；　is　an　extremely　difficult　object　at　which　to　take

effective　aim。



Seeing　that　even　a　small　captive　balloon　is　of　appreciable

dimensionsfrom　25　to　33　feet　or　more　in　diameterone　might

consider　it　an　easy　object　to　hit。　　But　experience　has　proved

otherwise。　　In　the　first　place　the　colour　of　the　balloon　is

distinctly　protective。　　The　golden　or　yellowish　tinge　harmonises

well　with　the　daylight；　even　in　gloomy　weather；　while　at

night…time　it　blends　excellently　with　the　moonlight。　　For

effective　observations　a　high　altitude　is　undesirable。　　At　a

height　of　600　feet　the　horizon　is　about　28　miles　from　the

observer；　as　compared　with　the　3　miles　constituting　the　range　of

vision　from　the　ground　over　perfectly　flat　country。　　Thus　it　will

be　seen　that　the　〃spotter〃　up　aloft　has　the　command　of　a

considerable　tract。



Various　ways　and　means　of　finding　the　range　of　a　captive　balloon

have　been　prepared；　and　tables　innumerable　are　available　for

committal　to　memory；　while　those　weapons　especially　designed　for

aerial　targets　are　fitted　with　excellent　range…finders　and　other

instruments。　　The　Germans；　with　characteristic　thoroughness；　have

devoted　considerable　attention　to　this　subject；　but　from　the

results　which　they　have　achieved　up　to　the　present　this　guiding

knowledge　appears　to　be　more　spectacular　and　impressive　than

effective。



To　put　a　captive　balloon　out　of　action　one　must　either　riddle　the

envelope；　causing　it　to　leak　like　a　sieve；　blow　the　vessel　to

pieces；　or　ignite　the　highly　inflammable　gas　with　which　it　is

inflated。　　Individual　rifle　fire　will　inflict　no　tangible　damage。

A　bullet；　if　it　finds　its　billet；　will　merely　pass　through　the

envelope　and　leave　two　small　punctures。　　True；　these　vents　will

allow　the　gas　to　escape；　but　this　action　will　proceed　so　slowly

as　to　permit　the　vessel　to　remain　aloft　long　enough　to　enable　the

observer　to　complete　his　work。　　A　lucky　rifle　volley；　or　the

stream　of　bullets　from　a　machine　gun　may　riddle　the　envelope；

precipitating　a　hurried　descent；　owing　to　the　greater　number　of

perforations　through　which　the　gas　is　able　to　escape；　but　as　a

rule　the　observer　will　be　able　to　land　safely。



Consequently　the　general　practice　is　to　shatter　the　aerostat；　and

to　this　end　either　shrapnel；　high　explosive；　or　incendiary　shells

will　be　used。　　The　former　must　explode　quite　close　to　the　balloon

in　order　to　achieve　the　desired　end；　while　the　incendiary　shell

must　actually　strike　it；　so　as　to　fire　the　gas。　　The　high

explosive　shell　may　explode　effectually　some　feet　away　from　the

vessel；　inasmuch　as　in　this　instance　dependence　is　placed　upon

the　terrific　concussion　produced　by　the　explosion　which；　acting

upon　the　fragile　fabric　of　the　balloon；　brings　about　a　complete

collapse　of　the　envelope。　　If　a　shrapnel　is　well　placed　and

explodes　immediately　above　the　balloon；　the　envelope　will　be　torn

to　shreds　and　a　violent　explosion　of　the　gas　will　be　precipitated。

But　as　a　matter　of　fact；　it　is　extremely　difficult　to　place　a

shrapnel　shell　so　as　to　consummate　this　end。　　The　range　is　not

picked　up　easily；　while　the　timing　of　the　fuse　to　bring　about　the

explosion　of　the　shell　at　the　critical　moment　is　invariably　a

complex　problem。



One　favourite　method　of　finding　the　range　of　a　balloon　is　shown

in　the　accompanying　diagrams。　　The　artillery　battery　is　at　B

and　the　captive　balloon；　C；　is　anchored　at　A。　　On　either

side　of　B　and　at　a　specified　distance；　observers　O1　and　O2　

respectively　are　stationed。　　First　a　shell　is　fired　at　〃long〃

range；　possibly　the　maximum　range　of　the　gun。　　It　bursts　at　D。　　

As　it　has　burst　immediately　in　the　line　of　sight　of　B；　but　with

the　smoke　obscured　by　the　figure　of　the　balloon　C；　it　is　obvious

to　B　that　the　explosion　has　occurred　behind　the　objective；　but　at

what　distance　he　cannot　tell。　　To　O1　and　O2；however；　it　is　seen

to　have　burst　at　a　considerable　distance　behind　C　though　to　the

former　it　appears　to　have　burst　to　the　left　and　to　the　second

observer　to　the　right　of　the　target。



Another　shell；　at　〃short〃　range；　is　now　fired；　and　it　bursts　at

E。　　The　explosion　takes　place　in　the　line　of　sight　of　B；　who

knows　that　he　has　fired　short　of　the　balloon　because　the　latter

is　eclipsed　by　the　smoke。　　But　the　two　observers　see　that　it　is

very　short；　and　here　again　the　explosion　appears　to　O1　to　have

occurred　to　the　right　of　the　target；　while　to　O2　it　has　evidently

burst　to　the　left　of　the　aerostat；　as　revealed　by　the　relation　of

the　position　of　the　balloon　to　the　bursting　of　the　shell　shown　in

Fig。　3。



A　third　round　is　fired；　and　the　shell　explodes　at　F。　　In　this

instance　the　explosion　takes　place　below　the　balloon。　　Both　the

observers　and　the　artillery　man　concur　in　their　deductions　upon

the　point　at　which　the　shell　burst。　　But　the　shell　must　explode

above　the　balloon；　and　accordingly　a　fourth　round　is　discharged

and　the　shell　bursts　at　G。



This　appears　to　be　above　the　balloon；　inasmuch　as　the　lines　of

sight　of　the　two　observers　and　B　converge　at　this　point。　　But

whether　the　explosion　occurs　immediately　above　the　vessel　as　is

desired；　it　is　impossible　to　say　definitely；　because　it　may

explode　too　far　behind　to　be　effective。　　Consequently；　if　this

shell　should　prove　abortive；　the　practice　is　to　decrease　the

range　gradually　with　each　succeeding　round　until　the　explosion

occurs　at　the　critical　point；　when；　of　course；　the　balloon　is

destroyed。　　An　interesting　idea　of　the　difficulty　of　picking　up

the　range　of　a　captive　balloon　may　be　gathered　from　the　fact　that

some　ten　minutes　are　required　to　complete　the　operation。



But　success　is　due　more　to　luck　than　judgment。　　In　the　foregoing

explanation　it　is　premised　that　the　aerial　vessel　remains

stationary；　which　is　an　ex　tremely　unlikely　contingency。　　While

those　upon　the　ground　are　striving　to　pick　up　the　range；　the

observer　is　equally　active　in　his　efforts　to　baffle　his

opponents。　　The　observer　follows　each　successive；　round　with　keen

interest；　and　when　the　shells　appear　to　be　bursting　at

uncomfortably　close　quarters　naturally　he　intimates　to　his

colleagues　below　that　he　desires　his　position　to　be　changed；

either　by　ascending　to　a　higher　point　or　descending。　　In　fact；　he

may　be　content　to　come　to　the　ground。　　Nor　must　the　fact　be

overlooked　that　while　the　enemy　is　trying　to　place　the　observer

hors　de　combat；　he　is　revealing　the　position　of　his　artillery；

and　the　observer　is　equally　industrious　in　picking　up　the　range

of　the　hostile　guns　for　the　benefit　of　his　friends　below。



When　the　captive　balloon　is　aloft　in　a　wind　the　chances　of　the

enemy　picking　up　the　range　thereof　are　extremely　slender；　as　it

is　continually　swinging　　to　and　fro。　　While　there　is　always　the

possibility　of　a　shell　bursting　at　such　a　lucky　moment　as　to

demolish　the　aerial　target；　it　is　generally　conceded　to　be

impossible　to　induce　a　shell　to　burst　within　100　yards　of　a

balloon；　no　matter　how　skilfully　the　hostile　battery　may　be

operated。



The　value　of　the　captive　balloon　has　been　demonstrated　very

strikingly　throughout　the　attack　upon　the　entrenched　German

positions　in　Flanders。　　Owing　to　the　undu