aeroplanes and dirigibles of war-第3章

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other　words；　the　balloon　should　be　directly　above　the　station

below；　so　that　if　100　yards　of　cable　are　paid　out　the　aerostat

may　be　100　yards　above　the　ground。　　If　a　wind　is　blowing；　the

helpless　craft　is　certain　to　be　caught　thereby　and　driven

forwards　or　backwards；　so　that　it　assumes　an　angle　to　its

station。　　If　this　become　acute　the　vessel　will　be　tilted；

rendering　the　position　of　the　observers　somewhat　precarious；　and

at　the　same　time　observing　efficiency　will　be　impaired。



This　point　may　be　appreciated　more　easily　by　reference　to　the

accompanying　diagram。　　A　represents　the　ground　station　and　B

the　position　of　the　captive　balloon　when　sent　aloft　in　calm

weather；　300　feet　of　cable　being　paid　out。　　A　wind　arises　and

blows　the　vessel　forward　to　the　position　C。　　At　this　point　the

height　of　the　craft　in　relation　to　the　ground　has　been　reduced；

and　the　reduction　must　increase　proportionately　as　the　strength

of　the　wind　increases　and　forces　the　balloon　still　more　towards

the　ground。　　At　the　same　time；　owing　to　the　tilt　given　to　the

car；　observation　is　rendered　more　difficult　and　eventually

becomes　extremely　dangerous。



A　wind；　if　of　appreciable　strength；　develops　another　and　graver

danger。　　Greater　strain　will　be　imposed　upon　the　cable；　while　if

the　wind　be　gusty；　there　is　the　risk　that　the　vessel　will　be　torn

away　from　its　anchoring　rope　and　possibly　lost。　　Thus　it　will　be

seen　that　the　effective　utilisation　of　a　captive　balloon　is

completely　governed　by　meteorological　conditions；　and　often　it　is

impossible　to　use　it　in　weather　which　exercises　but　little

influence　upon　dirigibles　or　aeroplanes。



The　captive　balloon　equipment　comprises　the　balloon；　together

with　the　observer's　basket；　the　wire…cable　whereby　it　is　anchored

and　controlled；　and　the　winding　apparatus。　　Formerly　a　steam

engine　was　necessary　for　the　paying　in　and　out　of　the　cable；　but

nowadays　this　is　accomplished　by　means　of　a　petrol…driven　motor；

an　oil…engine；　or　even　by　the　engine　of　an　automobile。　　The

length　of　cable　varies　according　to　the　capacity　of　the　balloon

and　the　maximum　operating　height。



The　average　British　balloon　is　able　to　lift　about　290　or　300

pounds；　which　may　be　taken　to　represent　the　weight　of　two

observers。　　On　the　other　hand；　the　French　and　German　balloons　are

able　to　carry　four　times　this　weight；　with　the　exception　of　the

French　auxiliaries；　which　are　designed　to　lift　one　observer　only。

The　balloons　of　the　two　latter　Powers　have　also　a　greater　maximum

altitude；　it　is　possible　to　ascend　to　a　height　of　some　2；000　feet

in　one　of　these。



The　observing　station　is　connected　with　the　winding　crew　below

either　by　a　telephone；　or　some　other　signalling　system；　the

method　practised　varying　according　to　circumstances。　　In　turn　the

winding　station　is　connected　with　the　officer　in　charge　of　the

artillery；　the　fire　of　which　the　captive　balloon　is　directing。　　

The　balloon　observer　is　generally　equipped　with　various

instruments；　such　as　telescope；　photographic　cameras；　and　so

forth；　so　as　to　be　able；　if　necessary；　to　prepare　a　topographical

survey　of　the　country　below。　　By　this　means　the　absence　of

reliable　maps　may　be　remedied；　or　if　not　regarded；　as

sufficiently　correct　they　may　be　checked　and　counter…checked　by

the　data　gained　aloft。



Seeing　that　the　gas　has　to　be　transported　in　cylinders；　which　are

weighty；　it　is　incumbent　that　the　waste　of　this　commodity　should

be　reduced　to　the　minimum。　　The　balloon　cannot　be　deflated　at

night　and　re…inflated　in　the　morningit　must　be　maintained　in

the　inflated　condition　the　whole　time　it　is　required　for

operation。



There　are　various　methods　of　consummating　this　end。　　One　method

is　to　haul　in　the　balloon　and　to　peg　it　down　on　all　sides；

completing　the　anchorage　by　the　attachment　of　bags　filled　with

earth　to　the　network。　　While　this　process　is　satisfactory　in　calm

weather；　it　is　impracticable　in　heavy　winds；　which　are　likely　to

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

resu