the life of thomas telford-第61章

按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！



half　in　diameter；　a　binding　of　gravel；　about　an　inch　in　thickness；

being　placed　over　all。　　A　drain　crossed　under　the　bed　of　the　bottom

layer　to　the　outside　ditch　in　every　hundred　yards。　　The　result　was

an　admirably　easy；　firm；　and　dry　road；　capable　of　being　travelled

upon　in　all　weathers；　and　standing　in　comparatively　small　need　of

repairs。



A　similar　practice　was　introduced　in　England　about　the　same　time　by

Mr。　Macadam；　and；　though　his　method　was　not　so　thorough　as　that　of

Telford；　it　was　usefully　employed　on　most　of　the　high　roads

throughout　the　kingdom。　　Mr。　Macadam's　notice　was　first　called　to

the　subject　while　acting　as　one　of　the　trustees　of　a　road　in

Ayrshire。　　Afterwards；　while　employed　as　Government　agent　for

victualling　the　navy　in　the　western　parts　of　England；　he　continued

the　study　of　road…making；　keeping　in　view　the　essential　conditions

of　a　compact　and　durable　substance　and　a　smooth　surface。　　At　that

time　the　attention　of　the　Legislature　was　not　so　much　directed　to

the　proper　making　and　mending　of　the　roads；　as　to　suiting　the

vehicles　to　them　such　as　they　were；　and　they　legislated　backwards

and　forwards　for　nearly　half　a　century　as　to　the　breadth　of　wheels。

Macadam　was；　on　the　other　hand；　of　opinion　that　the　main　point　was

to　attend　to　the　nature　of　the　roads　on　which　the　vehicles　were　to

travel。　　Most　roads　were　then　made　with　gravel；　or　flints　tumbled

upon　them　in　their　natural　state；　and　so　rounded　that　they　had　no

points　of　contact；　and　rarely　became　consolidated。　　When　a　heavy

vehicle　of　any　sort　passed　over　them；　their　loose　structure

presented　no　resistance；　the　material　was　thus　completely

disturbed；　and　they　often　became　almost　impassable。　　Macadam's

practice　was　this：　to　break　the　stones　into　angular　fragments；　so

that　a　bed　several　inches　in　depth　should　be　formed；　the　material

best　adapted　for　the　purpose　being　fragments　of　granite；

greenstone；　or　basalt；　to　watch　the　repairs　of　the　road　carefully

during　the　process　of　consolidation；　filling　up　the　inequalities

caused　by　the　traffic　passing　over　it；　until　a　hard　and　level

surface　had　been　obtained。　　Thus　made；　the　road　would　last　for

years　without　further　attention。　　in　1815　Mr。　Macadam　devoted

himself　with　great　enthusiasm　to　road…making　as　a　profession；　and

being　appointed　surveyor…general　of　the　Bristol　roads；　he　had　full

opportunities　of　exemplifying　his　system。　　It　proved　so　successful

that　the　example　set　by　him　was　quickly　followed　over　the　entire

kingdom。　　Even　the　streets　of　many　large　towns　were　Macadamised。

In　carrying　out　his　improvements；　however；　Mr。　Macadam　spent　several

thousand　pounds　of　his　own　money；　and　in　1825；　having　proved　this

expenditure　before　a　Committee　of　the　House　of　Commons；　the　amount

was　reimbursed　to　him；　together　with　an　honorary　tribute　of　two

thousand　pounds。　　Mr。　Macadam　died　poor；　but；　as　he　himself　said；

〃a　least　an　honest　man。〃　　By　his　indefatigable　exertions　and　his

success　as　a　road…maker；　by　greatly　saving　animal　labour；

facilitating　commercial　intercourse；　and　rendering　travelling　easy

and　expeditious；　he　entitled　himself　to　the　reputation　of　a　public

benefactor。



＇Image＇　J。　L。　Macadam。



Owing　to　the　mountainous　nature　of　the　country　through　which

Telford's　Carlisle　and　Glasgow　road　passes；　the　bridges　are

unusually　numerous　and　of　large　dimensions。　　Thus；　the　Fiddler's

Burn　Bridge　is　of　three　arches；　one　of　150　and　two　of　105　feet　span

each。　　There　are　fourteen　other　bridges；　presenting　from　one　to

three　arches；　of　from　20　to　90　feet　span。　　But　the　most　picturesque

and　remarkable　bridge　constructed　by　Telford　in　that　district　was

upon　another　line　of　road　subsequently　carried　out　by　him；　in　the

upper　part　of　the　county　of　Lanark；　and　crossing　the　main　line　of

the　Carlisle　and　Glasgow　road　almost　at　right　angles。　　Its　northern

and　eastern　part　formed　a　direct　line　of　communication　between　the

great　cattle　markets　of　Falkirk；　Crief；　and　Doune；　and　Carlisle　and

the　West　of　England。　　It　was　carried　over　deep　ravines　by　several

lofty　bridges；　the　most　formidable　of　which　was　that　across　the

Mouse　Water　at　Cartland　Crags；　about　a　mile　to　the　west　of　Lanark。

The　stream　here　flows　through　a　deep　rocky　chasm；　the　sides　of

which　are　in　some　places　about　four　hundred　feet　high。　　At　a　point

where　the　height　of　the　rocks　is　considerably　less；　but　still　most

formidable；　Telford　spanned　the　ravine　with　the　beautiful　bridge

represented　in　the　engraving　facing　this　page；　its　parapet　being

129　feet　above　the　surface　of　the　water　beneath。



＇Image＇　Cartland　Crags　Bridge。



The　reconstruction　of　the　western　road　from　Carlisle　to　Glasgow；

which　Telford　had　thus　satisfactorily　carried　out；　shortly　led　to

similar　demands　from　the　population　on　the　eastern　side　of　the

kingdom。　　The　spirit　of　road　reform　was　now　fairly　on　foot。

Fast　coaches　and　wheel…carriages　of　all　kinds　had　become　greatly

improved；　so　that　the　usual　rate　of　travelling　had　advanced　from

five　or　six　to　nine　or　ten　miles　an　hour。　　The　desire　for　the　rapid

communication　of　political　and　commercial　intelligence　was　found　to

increase　with　the　facilities　for　supplying　it；　and；　urged　by　the

public　wants；　the　Post…Office　authorities　were　stimulated　to

unusual　efforts　in　this　direction。　　Numerous　surveys　were　made　and

roads　laid　out；　so　as　to　improve　the　main　line　of　communication

between　London　and　Edinburgh　and　the　intermediate　towns。　　The　first

part　of　this　road　taken　in　hand　was　the　worstthat　lying　to　the

north　of　Catterick　Bridge；　in　Yorkshire。　　A　new　line　was　surveyed　by

West　Auckland　to　Hexham；　passing　over　Garter　Fell　to　Jedburgh；　and

thence　to　Edinburgh；　but　was　rejected　as　too　crooked　and　uneven。

Another　was　tried　by　Aldstone　Moor　and　Bewcastle；　and　rejected　for

the　same　reason。　　The　third　line　proposed　was　eventually　adopted　as

the　best；　passing　from　Morpeth；　by　Wooler　and　Coldstream；

to　Edinburgh；　saving　rather　more　than　fourteen　miles　between　the

two　points；　and　securing　a　line　of　road　of　much　more　favourable

gradients。



The　principal　bridge　on　this　new　highway　was　at　Pathhead；　over　the

Tyne；　about　eleven　miles　south　of　Edinburgh。　　To　maintain　the

level；　so　as　to　avoid　the　winding　of　the　road　down　a　steep　descent

on　one　side　of　the　valley　and　up　an　equally　steep　ascent　on　the

other；　Telford　ran　out　a　lofty　embankment　from　both　sides；

connecting　their　ends　by　means　of　a　spacious　bridge。　　The　structure

at　Pathhead　is　of　five　arches；　each　50　feet　span；　with　25　feet　rise

from　their　springing；　49　feet　above　the　bed　of　the　river。　　Bridges

of　a　similar　character　were　also　thrown　over　the　deep　ravines　of

Cranston　Dean　and　Cotty　Burn；　in　the　same　neighbourhood。　　At　the

same　time　a　useful　bridge　was　built　on　the　same　line　of　road　at

Morpeth；　in　Northumberland；　over　the　river　Wansbeck。　　It　consisted

of　three　arches；　of　which　the　centre　one　was　50　feet　span；　and　two

side…arches　40　feet　each；　the　breadth　between　the　parapets　being　30

feet。



The　advantages　derived　from　the　construction　of　these　new　roads

were　found　to　be　so　great；　that　it　was　proposed　to　do　the　like　for

the　remainder　of　the　line　between　London　and　Edinburgh；　and　at　the

instance　of　the　Post…Office　authorities；　with　the　sanction　of　the

Treasury；　Mr。　Telford　proceeded　to　make　detailed　surveys　of　an

entire　new　post…road　between　London　and　Morpeth。　　In　laying　it　out；

the　main　points　which　he　endeavoured　to　secure　were　directness　and

flatness；　and　100　miles　of　the　proposed　new　Great　North　Road；　south

of　York；　were　laid　out　in　a　perfectly　straight　line。　　This　survey；

which　was　begun　in　1824；　extended　over　several　years；　and　all　the

requisite　arrangements　had　been　made　for　beginning　the　works；　when

the　result　of　the　locomotive　competition　at　Rainhill；　in　1829；　had

the　effect　of　directing　attention　to　that　new　method　of　travelling；

fortunately　in　time　to　prevent　what　would　have　proved；　for　the　most

part；　an　unnecessary　expenditure；　o