the life of thomas telford-第51部分

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in　some　parts　of　deep　clay；　in　others　of　deep　sand。　　A　mail…coach

had　been　tried　to　Banbury；　but　the　road　below　Aylesbury　was　so　bad；

that　the　Post…office　authorities　were　obliged　to　give　it　up。　　The

twelve　miles　from　Towcester　to　Daventry　were　still　worse。　　The　line

of　way　was　covered　with　banks　of　dirt；　in　winter　it　was　a　puddle　of

from　four　to　six　inches　deepquite　as　bad　as　it　had　been　in　Arthur

Young's　time；　and　when　horses　passed　along　the　road；　they　came　out

of　it　a　mass　of　mud　and　mire。*＇7＇　　There　were　also　several　steep　and

dangerous　hills　to　be　crossed；　and　the　loss　of　horses　by　fatigue　in

travelling　by　that　route　at　the　time　was　very　great。



Even　the　roads　in　the　immediate　neighbourhood　of　the　metropolis

were　little　better；　those　under　the　Highgate　and　Hampstead　trust

being　pronounced　in　a　wretched　state。　　They　were　badly　formed；

on　a　clay　bottom；　and　being　undrained；　were　almost　always　wet　and

sloppy。　　The　gravel　was　usually　tumbled　on　and　spread　unbroken；

so　that　the　materials；　instead　of　becoming　consolidated；　were　only

rolled　about　by　the　wheels　of　the　carriages　passing　over　them。



Mr。　Telford　applied　the　same　methods　in　the　reconstruction　of　these

roads　that　he　had　already　adopted　in　Scotland　and　Wales；　and　the

same　improvement　was　shortly　felt　in　the　more　easy　passage　over

them　of　vehicles　of　all　sorts；　and　in　the　great　acceleration　of　the

mail　service。　　At　the　same　time；　the　line　along　the　coast　from

Bangor；　by　Conway；　Abergele；　St。　Asaph；　and　Holywell；　to　Chester；

was　greatly　improved。　　As　forming　the　mail　road　from　Dublin　to

Liverpool；　it　was　considered　of　importance　to　render　it　as　safe

and　level　as　possible。　　The　principal　new　cuts　on　this　line　were

those　along　the　rugged　skirts　of　the　huge　Penmaen…Mawr；　around　the

base　of　Penmaen…Bach　to　the　town　of　Conway；　and　between　St。　Asaph

and　Holywell；　to　ease　the　ascent　of　Rhyall　Hill。



But　more　important　than　all；　as　a　means　of　completing　the　main　line

of　communication　between　England　and　Ireland；　there　were　the　great

bridges　over　the　Conway　and　the　Menai　Straits　to　be　constructed。

The　dangerous　ferries　at　those　places　had　still　to　be　crossed　in

open　boats；　sometimes　in　the　night；　when　the　luggage　and　mails　were

exposed　to　great　risks。　　Sometimes；　indeed；　they　were　wholly　lost

and　passengers　were　lost　with　them。　　It　was　therefore　determined；

after　long　consideration；　to　erect　bridges　over　these　formidable

straits；　and　Mr。　Telford　was　employed　to　execute　the　works；in

what　manner；　we　propose　to　describe　in　the　next　chapter。



Footnotes　for　Chapter　XI。



*＇1＇　'Life　of　Robert　Owen；'　by　himself。



*＇2＇　'Report　from　the　Select　Committee　on　the　Carlisle　and　Glasgow

Road；'　28th　June；　1815。



*＇3　A　diary　is　preserved　of　a　journey　to　Dublin　from　Grosvenor

Square　London；　l2th　June；　1787；　in　a　coach　and　four；　accompanied　by

a　post…chaise　and　pair；　and　five　outriders。　　The　party　reached

Holyhead　in　four　days；　at　a　cost　of　75L。　11s。　3d。　The　state　of

intercourse　between　this　country　and　the　sister　island　at　this　part

of　the　account　is　strikingly　set　forth　in　the　following　entries：

〃Ferry　at　Bangor；　1L。　10s。；　expenses　of　the　yacht　hired　to　carry

the　party　across　the　channel；　28L。　7s。　9d。；　duty　on　the　coach；　7L。

13s。　4d。；　boats　on　shore；　1L。　1s。；　total；　114L。　3s。　4d。〃

Roberts's　'Social　History　of　the　Southern　Counties；'　p。　504。



*＇4＇　'Second　Report　from　Committee　on　Holyhead　Roads　and　Harbours；'

1810。　　（Parliamentary　paper。）



*＇5＇　〃Many　parts　of　the　road　are　extremely　dangerous　for　a　coach　to

travel　upon。　　At　several　places　between　Bangor　and　Capel…Curig　there

are　a　number　of　dangerous　precipices　without　fences；　exclusive　of

various　hills　that　want　taking　down。　　At　Ogwen　Pool　there　is　a　very

dangerous　place　where　the　water　runs　over　the　road；　extremely

difficult　to　pass　at　flooded　times。　　Then　there　is　Dinas　Hill；　that

needs　a　side　fence　against　a　deep　precipice。　　The　width　of　the　road

is　not　above　twelve　feet　in　the　steepest　part　of　the　hill；　and　two

carriages　cannot　pass　without　the　greatest　danger。　　Between　this

hill　and　Rhyddlanfair　there　are　a　number　of　dangerous　precipices；

steep　hills；　and　difficult　narrow　turnings。　　From　Corwen　to

Llangollen　the　road　is　very　narrow；　long；　and　steep；　has　no　side

fence；　except　about　a　foot　and　a　half　of　mould　or　dirt；　which　is

thrown　up　to　prevent　carriages　falling　down　three　or　four　hundred

feet　into　the　river　Dee。　　Stage…coaches　have　been　frequently

overturned　and　broken　down　from　the　badness　of　the　road；　and　the

mails　have　been　overturned；　but　I　wonder　that　more　and　worse

accidents　have　not　happened；　the　roads　are　so　bad。〃Evidence　of

Mr。　William　Akers；　of　the　Post…office；　before　Committee　of　the

House　of　Commons；　1st　June；　1815。



*＇6＇　The　Select　Committee　of　the　House　of　Commons；　in　reporting　as

to　the　manner　in　which　these　works　were　carried　out；　stated　as

follows：　〃The　professional　execution　of　the　new　works　upon　this

road　greatly　surpasses　anything　of　the　same　kind　in　these

countries。　　The　science　which　has　been　displayed　in　giving　the

general　line　of　the　road　a　proper　inclination　through　a　country

whose　whole　surface　consists　of　a　succession　of　rocks；　bogs；

ravines；　rivers；　and　precipices；　reflects　the　greatest　credit　upon

the　engineer　who　has　planned　them；　but　perhaps　a　still　greater

degree　of　professional　skill　has　been　shown　in　the　construction；　or

rather　the　building；　of　the　road　itself。　　The　great　attention　which

Mr。　Telford　has　devoted；　to　give　to　the　surface　of　the　road　one

uniform　and　moderately　convex　shape；　free　from　the　smallest

inequality　throughout　its　whole　breadth；　the　numerous　land　drains；

and；　when　necessary；　shores　and　tunnels　of　substantial　masonry；

with　which　all　the　water　arising　from　springs　or　falling　in　rain　is

instantly　carried　off；　the　great　care　with　which　a　sufficient

foundation　is　established　for　the　road；　and　the　quality；　solidity；

and　disposition　of　the　materials　that　are　put　upon　it；　are　matters

quite　new　in　the　system　of　road…making　in　these　countries。〃

'Report　from　the　Select　Committee　on　the　Road　from　London　to

Holyhead　in　the　year　1819。'



*＇7＇　Evidence　of　William　Waterhouse　before　the　Select　Committee；

10th　March；　1819。





CHAPTER　XII。



THE　MENAI　AND　CONWAY　BRIDGES。



＇Image＇　Map　of　Menai　Strait　＇Ordnance　Survey＇



So　long　as　the　dangerous　Straits　of　Menai　had　to　be　crossed　in　an

open　ferry…boat；　the　communication　between　London　and　Holyhead　was

necessarily　considered　incomplete。　　While　the　roads　through　North

Wales　were　so　dangerous　as　to　deter　travellers　between　England　and

Ireland　from　using　that　route；　the　completion　of　the　remaining　link

of　communication　across　the　Straits　was　of　comparatively　little

importance。　　But　when　those　roads　had；　by　the　application　of　much

capital；　skill；　and　labour；　been　rendered　so　safe　and　convenient

that　the　mail　and　stage　coaches　could　run　over　them　at　the　rate　of

from　eight　to　ten　miles　an　hour；　the　bridging　of　the　Straits　became

a　measure　of　urgent　public　necessity。　　The　increased　traffic　by　this

route　so　much　increased　the　quantity　of　passengers　and　luggage；

that　the　open　boats　were　often　dangerously　overloaded；　and　serious

accidents；　attended　with　loss　of　life　and　property；　came　to　be　of

frequent　occurrence。



The　erection　of　a　bridge　over　the　Straits　had　long　been　matter　of

speculation　amongst　engineers。　　As　early　as　1776；　Mr。　Golborne

proposed　his　plan　of　an　embankment　with　a　bridge　in　the　middle　of　it；

and　a　few　years　later；　in　1785；　Mr。　Nichols　proposed　a　wooden

viaduct；　furnished　with　drawbridges　at　Cadnant　Island。　　Later　still；

Mr。　Rennie　proposed　his　design　of　a　cast　iron　bridge。　　But　none　of

these　plans　were　carried　out；　and　the　whole　subject　remained　in

abeyance　until　the　year　1810；　when　a　commission　was　appointed　to

inquire　and　report　as　to　the　state　of　the　roads　between　Shrewsbury；

Chester；　and　Holyhead。　　The　result　was；　that　Mr。　Telford　was　called

upon　to　report　as　to　the　most　effectual　method　of　bridging　the

Menai　Strait；　and　thus　completing　the　communication　with　the　port

of　embarkation　for　Ireland。



＇Image＇　Telford's　proposed　Cast　Iron　Bridge



Mr。　Telford　submitted　alternative　plans　for　a　bridge　over　the

Strait：　one　at　the　Swilly　Rock；　consisting　of　three　cast　iron

arches　of　260　feet　span；　with　a　stone　arch　of　100　feet　span　between

each　two　iron　ones；　to　resist　their　lateral　thrust；　and　another　at

Ynys…y…moch；　to　which　he　himself　attached　the　preference；

consisting　of　a　single　cast　iron　arch　of　500　feet　span；　the　crown

of　the　arch　to　be　100　feet　above　high　water　of　spring　tides；　and

the　breadth　of　the　roadway　to　be　40　feet。



The　principal　objection　taken　to　this　plan　by　engineers　generally；

was　the　supposed　difficulty　of　erecting　a　proper　centering　to

support　the　arch　during　construction；　and　the　mode　by　which

Mr。　Telford　proposed　to　overcome　this　may　be　cited　in　illustration

of　his　ready　ingenuity　in　overcoming　difficulties。　　He　proposed　to

suspend　the　centering　from　above　instead　of　supporting　it　from

below　in　the　usual　mannera　contrivance　afterwards　revived　by

another　very　skilful　engineer；　the　late　Mr。　Brunel。　　Frames；　50　feet

high；　were　to　be　erected　on　the　top　of　the　abutments；　and　on　these；

strong　blocks；　or　rollers　and　chains；　were　to　be　fixed；　by　means　of

which；　and　by　the　aid　of　windlasses　and　other　mechanical　powers；

each　separate　piece　of　centering　was　to　be　raised　into；　and

suspended　in；　its　proper　place。　　Mr。　Telford　regarded　this　method　of

constructing　centres　as　applicable　to　stone　as　well　as　to　iron

arches；　and　indeed　it　is　applicable；　as　Mr。　Brunel　held；　to　the

building　of　the　arch　itself。*＇1＇



＇Image＇　Proposed　Plan　of　Suspended　Centering



Mr。　Telford　anticipated　that；　if　the　method　recommended　by　him　were

successfully　adopted　on　the　large　scale　proposed　at　Menai；　all

difficulties　with　regard　to　carrying　bridges　over　dee