,transcrib]'s note3 ,?is is ,pap] #da f ! ,smi?sonian ,in/itution ,unit$ ,/ates ,national ,museum ,bullet9 #bdj1 compris+ ,pap]s #cd-dd1 :i* w also be available z a complete e-book4 ,! front mat]ial1 introduction & relevant index entries f ! ,bullet9 are includ$ 9 ea* s+le-pap] e-book4 ,italic emphasis d5ot$ z ,text4 ,:ole numb]s & fractions3 %[n z #a-a_/b1 #c-a_/d1 etc4 ,please see ! end ( ! book = corrections & *anges made4 ,smi?sonian ,in/itution ,unit$ ,/ates ,national ,museum ,bullet9 #bdj ,illu/ration3 ,smi?sonian ,press ,museum ( ,hi/ory & ,te*nology ,contributions f ! ,museum ( ,hi/ory & ,te*nology ,pap]s #cd-dd ,on ,sci5ce & ,te*nology ,smi?sonian ,in/itution 4 ,wa%+ton1 ,d4,c4 #aiff 99 99 99 99 99 ,publications ( ! ,unit$ ,/ates ,national ,museum ,! s*ol>ly & sci5tific publications ( ! ,unit$ ,/ates ,national ,museum include two s]ies1 ,proce$+s ( ! ,unit$ ,/ates ,national ,museum & ,unit$ ,/ates ,national ,museum ,bullet94 ,9 ^! s]ies1 ! ,museum publi%es orig9al articles & monographs deal+ ) ! collections & "w ( its con/itu5t museums--,! ,museum ( ,natural ,hi/ory & ! ,museum ( ,hi/ory & ,te*nology--sett+ =? newly acquir$ facts 9 ! fields ( an?ropology1 biology1 hi/ory1 geology1 & te*nology4 ,copies ( ea* publication are di/ribut$ to libr>ies1 to cultural & sci5tific organizations1 & to speciali/s & o!rs int]e/$ 9 ! diff]5t subjects4 ,! ,proce$+s1 begun 9 #ahgh1 are int5d$ = ! publication1 9 sep>ate =m1 ( %ort] pap]s f ! ,museum ( ,natural ,hi/ory4 ,^! are ga!r$ 9 volumes1 octavo 9 size1 ) ! publication date ( ea* pap] record$ 9 ! table ( cont5ts ( ! volume4 ,9 ! ,bullet9 s]ies1 ! fir/ ( :i* 0 issu$ 9 #ahge1 appe> long]1 sep>ate publications consi/+ ( monographs 7occasionally 9 sev]al p>ts7 & volumes 9 :i* are collect$ works on relat$ subjects4 ,bullet9s are ei!r octavo or qu>to 9 size1 dep5d+ on ! ne$s ( ! pres5tation4 ,s9ce #aijb pap]s relat+ to ! botanical collections ( ! ,museum ( ,natural ,hi/ory h be5 publi%$ 9 ! ,bullet9 s]ies "u ! head+ ,contributions f ! ,unit$ ,/ates ,national ,h]b>ium1 & s9ce #aiei1 9 ,bullet9s titl$ ,contributions f ! ,museum ( ,hi/ory & ,te*nology1 h be5 ga!r$ %ort] pap]s relat+ to ! collections & rese>* ( t ,museum4 ,! pres5t collection ( ,contributions1 ,pap]s #cd-dd1 comprises ,bullet9 #bdj4 ,ea* ( ^! pap]s has be5 previ\sly publi%$ 9 sep>ate =m4 ,! ye> ( publication is %[n on ! la/ page ( ea* pap]4 ,,frank ,a4 ,,taylor ,director1 ,unit$ ,/ates ,national ,museum 99 99 99 99 99 ,,contributions ,,f ,,! ,,museum ,,( ,,hi/ory ,,& ,,te*nology4 ,,pap] #da ,,tunnel ,,eng9e]+--,a ,,museum ,,treatm5t ,rob]t ,m4 ,vogel ,,introduction #bjc ,,rock ,,tunnel+ #bjf ,,s(t-,,gr\nd ,,tunnel+ #bae ,,bibliography #bci ,,footnotes ,,index ,illu/ration3 ,figure #a4--,,m9+ ,,by ,,e>ly ,,european ,,civilizations1 us+ fire sett+ & h& *isel+ to break out ore & rock4 ,,mht model--#c_/d scale4 7,smi?sonian photo #dibfj-;,h47 ,rob]t ,m4 ,vogel ,,tunnel ,,eng9e]+--,a ,,museum ,,treatm5t ,dur+ ! ye>s f #ahcj to #aijj1 ext5sive developm5ts took place 9 ! field ( tunnel+1 :i* today is an important1 firmly e/abli%$ bran* ( civil eng9e]+4 ,?is pap] (f]s a picture ( its gr[? f ! hi/orical /&po9t1 bas$ on a s]ies ( models con/ruct$ = ! ,hall ( ,civil ,eng9e]+ 9 ! new ,museum ( ,hi/ory & ,te*nology4 ,! eight models describ$ highlight ! fundam5tal advances :i* h occurr$ betwe5 primitive man's fir/ sy/ematic use ( fire = excavat+ rock 9 m9+1 & ! use 9 comb9ation ( compress$ air1 an iron l9+1 & a movable %ield 9 a subaque\s tunnel at ! end ( ! #ai? c5tury4 ,,! ,,au?or3 ,rob]t ,m4 ,vogel is curator ( heavy ma*9]y & civil eng9e]+1 9 ! ,smi?sonian ,in/itution's ,museum ( ,hi/ory & ,te*nology4 ,introduction ,) few exceptions1 civil eng9e]+ is a field 9 :i* ! ultimate goal is ! assemblage ( mat]ials into a useful /ructural =m accord+ to a sci5tifically d]iv$ plan :i* is bas$ on v>i\s natural & man-impos$ conditions4 ,?is is true :e!r ! result be1 = example1 a dam1 a build+1 a bridge1 or ev5 ! fix$ plant ( a railroad4 ,h[ev]1 "o pr9cipal bran* ( ! field is bas$ ^u an entirely diff]5t concept4 ,9 ! eng9e]+ ( tunnels ! utility ( ! /ructure is d]iv$ n f ! br++ toge!r ( elem5ts b f ! sep>ation ( "o portion ( naturally exi/+ mat]ial f ano!r to p]mit passage ?r\gh a =m] b>ri]4 ,9 tunnel+ h>d1 firm rock1 ?is is practically ! entire compass ( ! "w3 break+ away ! rock f ! "m mass1 &1 co9cid5tly1 remov+ x f ! work+s4 ,! opposite extreme 9 conditions is met 9 ! s(t-gr\nd tunnel1 driv5 ?r\gh mat]ial incapable ( support+ itself above ! tunnel op5+4 ,"h1 ! excavation ( ! tunnel$ sub/ance is ( relatively small conc]n1 eclips$ by ! problem ( prev5t+ ! surr\nd+ mat]ial f collaps+ into ! bore4 ,illu/ration3 ,figure #b4--;,,hoosac ,,tunnel4 ,,me?od ,,( ,,work+ ,,e>ly ,,sections ( ! project2 bla/ holes drill$ by h& jack+4 ,,mht model--#a_/b scale4 7,smi?sonian photo #dibfj-,l47 ,9 "o o!r pr9cipal respect does tunnel eng9e]+ diff] widely f its collat]al bran*es ( civil eng9e]+4 ,few o!r physical und]tak+s are approa*$ ) any?+ l ! unc]ta9ty att5d+ a tunnel "w4 ,?is is ev5 m true 9 m\nta9 tunnels1 = :i* te/ bor+s frequ5tly _c be made to det]m9e ! nature ( ! mat]ial & ! geologic conditions :i* w be enc\nt]$4 ,! c\rse ( tunnel "w is n subject to an ov]all prelim9>y survey2 ! eng9e] is fac$ ) n only ! inability to anticipate g5]al cont+5cies common to all eng9e]+ "w1 b ) ! peculi> & (t5 ov]:elm+ unpr$ictability ( ! v basis ( 8 "w4 ,subaque\s & s(t-gr\nd "w on ! o!r h&1 :ile /ill subject to _m indet]m9ates1 is n[ f> m pr$ictable ?an dur+ its e>ly hi/ory1 simply because ! nature ( ! adv]se condition prevail+ ev5tually 0 und]/ood to be q pr$ictable4 ,! /eady pressures ( e>? & wat] to refill ! excavat$ area are today ov]come ) relative ease & consi/5cy by ! tunnel]4 ,9 tunnel+ z 9 no o!r bran* ( civil eng9e]+ did empiricism s long resi/ ! advance ( sci5tific !ory2 9 no o!r did ! practical eng9e] rema9 to su* an ext5t ! key figure 9 e/abli%+ ! success or failure ( a project4 ,! ,hoosac ,tunnel1 aft] #be ye>s ( legislative1 f9ancial1 & te*nical difficulties1 9 #ahge 0 f9ally driv5 to successful completion only by ! ef=ts ( a gr\p :o1 :ile 9 ! majority 7 tra9$ civil eng9e]s1 7 to an ev5 great] ext5t m5 ( va/ practical ability1 m at home 9 field ?an (fice4 ,de,witt ,c4 ,hask9 7see p4 #bcd71 dur+ ! inque/ t foll[$ ! dea? ( a numb] ( m5 9 a bl[\t ( 8 pneumatically driv5 ,hudson ,riv] ,tunnel 9 #ahhj1 /at$ 9 8 own def5se3 ,i am n a sci5tific eng9e]1 b a practical "o 444 ,i "k no?+ ( ma!matics2 9 my exp]i5ce ,i h grasp$ su* matt]s z a :ole2 ,i believe t ! /udy ( ma!matics 9 t k9d ( "w tunnel+ has a t5d5cy to dw>f ! m9d r ?an enlight5 x4444 ,an extreme attitude p]haps1 & "o :i* by no means adds to ,hask9's /ature1 b a n unusual "o 9 tunnel "w at ! "t4 ,x w\ld n ( c\rse be fair to imply t su* m5 z ,h]man ,haupt1 ,brunel ! eld]1 & ,grea!ad 7 n accompli%$ !oretical eng9e]s4 ,b x 0 _! innate ability to evaluate & control ! ov]ly+ physical conditions ( ! site & "w t made possible _! significant contributions to ! developm5t ( tunnel eng9e]+4 ,tunnel+ rema9$ l>gely indep5d5t ( ! realm ( ma!matical analysis long aft] ! "t :5 all b ! mo/ insignificant eng9e]+ works 7 design$ by t means4 ,?us1 z /ructural eng9e]+ has advanc$ z ! result ( a fl[ ( new !oretical concepts1 new1 improv$1 & /r5g!n$ mat]ials1 & new me?ods ( fa/5+1 ! progress ( tunnel eng9e]+ has be5 due m to ! cont9ual ref9em5t ( con/ructional te*niques4 ,a ,,new ,,hall ,,( ,,civil ,,eng9e]+ ,9 ! ,museum ( ,hi/ory & ,te*nology has rec5tly be5 e/abli%$ a ,hall ( ,civil ,eng9e]+ 9 :i* ! eng9e]+ ( tunnels is compreh5sively treat$ f ! hi/orical /&po9t--some?+ n previ\sly done 9 an ,am]ican museum4 ,! guid+ precept ( ! exhibit has n be5 to outl9e exhau/ively ! entire hi/ory ( tunnel+1 b r to %[ ! fundam5tal advances :i* h occurr$ betwe5 primitive man's fir/ sy/ematic use ( fire = excavat+ rock 9 m9+1 & ! use 9 comb9ation ( compress$ air1 iron l9+1 & a movable %ield 9 a subaque\s tunnel at ! end ( ! #ai? c5tury4 ,?is t]m9ation date 0 select$ because x 0 dur+ ! p]iod f ab\t #ahcj to #aijj t ! mo/ conc5trat$ developm5t took place1 & dur+ :i* tunnel+ became a firmly e/abli%$ & important bran* ( civil eng9e]+ & inde$1 ( mod]n civilization4 ,! te*niques ( pres5t-day tunnel+ are s fully relat$ 9 curr5t writ+ t x 0 deem$ f> m useful to devote ! exhibit entirely to a segm5t ( ! field's hi/ory :i* is less commonly treat$4 ,illu/ration3 ,figure #c4--;,,hoosac ,,tunnel4 ,,work+ ,,( ,,lat] ,,/ages ) ,burleigh pneumatic drills m\nt$ on c>riages4 ,! bottom head+ is be+ drill$ 9 prep>ation = bla/+ out ) nitroglyc]9e4 ,,mht model--#a_/b scale4 7,smi?sonian photo #dibfj-,m47 ,! major advances1 :i* h already be5 spok5 ( z be+ ones ( te*nique r ?an !ory1 devolve q naturally into two basic classifications3 ! "o ( support+ a mass ( loose1 un/able1 pressure-ex]t+ mat]ial--s(t-gr\nd tunnel+2 & ! diametrically opposite problem ( sep>at+ rock f ! basic mass :5 x is s firm & solid t x c support its own ov]be>+ weight z an op5+ is =c$ ?r\gh x--rock1 or h>d-gr\nd tunnel+4 ,to exhibit ! sequ5ce 9 a ?or\gh mann]1 invit+ & capable ( easy & correct int]pretation by ! nonpr(essional view]1 models (f]$ ! only logical means ( pres5tation4 ,six tunnels 7 select$1 all driv5 9 ! #ai? c5tury4 ,ea* repres5ts ei!r a fundam5tal1 new concept ( tunnel+ te*nique1 or an important1 e>ly application ( "o4 ,models ( ^! works =m ! basis ( ! exhibit4 ,no ef=t 0 made to re/rict ! "w to projects on ,am]ican soil4 ,?is w\ld1 9 fact1 h be5 q impossible if an accurate picture ( tunnel te*nology 0 to be drawn2 = z 9 virtually all o!r areas ( te*nology1 ! ov]all developm5t 9 ?is field has be5 int]national4 ,! art ( m9+ 0 fir/ develop$ highly 9 ! ,middle ,ages 9 ! ,g]manic /ates2 ! tunnel %ield 0 inv5t$ by a ,fr5*man resid+ 9 ,engl&1 & ! use ( compress$ air to exclude ! wat] f subaque\s tunnels 0 fir/ introduc$ on a major "w by an ,am]ican4 ,9 addition1 ! two ma9 subdivisions1 rock & s(t-gr\nd tunnel+1 are ea* introduc$ by a model n ( an actual work+1 b ( "o typify+ e>ly classical me?ods :i* 7 9 use = c5turies until ! comp>atively rec5t developm5t ( m effici5t sy/ems ( e>? support & rock break+4 ,p>ticul> att5tion is giv5 to accuracy ( detail ?r\gh\t ! s]ies ( eight models2 orig9al s\rces ( descriptive & graphic in=mation 7 us$ 9 _! con/ruction :]ev] possible4 ,9 all cases except ! introductory model 9 ! rock-tunnel+ s]ies1 repres5t+ copp] m9+ by e>ly civilizations1 ^! s\rces 7 contempor>y acc\nts4 ,! plan to use a uni=m scale ( r$uction ?r\gh\t1 9 ord] to facilitate ! view]s' int]pretation1 un=tunately prov$ impractical1 due to ! great diff]5ce 9 ! am\nt ( area to be encompass$ 9 diff]5t models1 & ! necessity t ! cases hold+ !m be ( uni=m height4 ,! relat$ models ( ! ,broadway & ,t[] ,subways repres5t %ort sections ( tunnels only #h feet or s 9 diamet] enabl+ a relatively l>ge scale1 #a-a_/b in*es to ! foot1 to be us$4 ,conv]sely1 9 ord] t ! model ( ,brunel's ,?ames ,tunnel be mo/ effective1 x 0 necess>y to include "o ( ! v]tical t]m9al %afts us$ 9 its con/ruction4 ,^! 7 ab\t #fj feet 9 dep?1 & ?us ! mu* small] scale ( #a_/d in* to ! foot 0 us$4 ,?is v>iation is n z confus+ z might be ?\ght1 = ! human figures 9 ea* model provide an imm$iate & positive s5se ( proportion & scale4 ,c>eful ?\ght 0 devot$ to ! int]nal light+ ( ! models1 z ?is 0 "o ( ! critical factors 9 e/abli%+1 s f> z is possible 9 a model1 an atmosph]e conv9c+ly repres5tative ( "w conduct$ solely by artificial light4 ,rem>kable realism 0 a*iev$ by use ( pla/ic rods to conduct light to ! t9y s\rces ( tunnel illum9ation1 su* z ! c&les on ! m9]s' hats 9 ! ,hoosac ,tunnel1 & ! gas lights 9 ! ,?ames ,tunnel4 ,no ov]scal$ m9iature bulbs1 g5]ally appli$ 9 su* cases1 7 us$4 ,at sev]al po9ts :]e ! g5]al light+ )9 ! tunnel prop] has be5 kept at a l[ level to simulate ! natural atmosph]e ( ! "w1 hidd5 lamps c be op]at$ by pu%-button 9 ord] to br+ out detail :i* o!rwise w\ld be unse54 ,! rema9d] ( ! mat]ial 9 ! ,museum's tunnel+ section fur!r ext5ds ! two major aspects ( tunnel+4 ,space limitations did n p]mit treatm5t ( ! _m int]e/+ ancill>y matt]s vital to tunnel eng9e]+1 su* z ! unique problems ( subt]ranean survey+1 & ! extreme accuracy requir$ 9 ! triangulation & subsequ5t guidance ( ! bor+ 9 long m\nta9 tunnels2 nor ! difficult problems ( v5tilat+ long work+s1 bo? dur+ driv+ & 9 s]vice2 nor ! sev]al major me?ods develop$ ?r\gh ! ye>s = driv+ or con/ruct+ tunnels 9 o!r ?an ! conv5tional mann]4#a ,rock ,tunnel+ ,:ile ! art ( tunnel+ s(t gr\nd is ( relatively rec5t orig91 t ( rock tunnel+ is deeply root$ 9 antiquity4 ,h[ev]1 ! l9e ( its developm5t is n absolutely direct1 b is m logically foll[$ ?r\gh a closely relat$ bran* ( te*nology--m9+4 ,! developm5t ( m9+ te*niques is a practically unbrok5 "o1 :]eas !re appe>s little cont9uity or relation%ip betwe5 ! few works und]tak5 be=e ab\t ! #ah? c5tury = passage ?r\gh ! e>?4 ,! ,egyptians 7 ! fir/ p 9 record$ hi/ory to h driv5 op5+s1 (t5 ( consid]able magnitude1 ?r\gh solid rock4 ,z is true ( all major works ( t nation1 ! capability ( su* gr& proportion 0 due solely to ! inexhau/ible supply ( human p[] & ! casual evaluation ( life4 ,! tombs & temples won f ! rock masses ( ! ,nile ,valley are monum5ts ( p]sev]ance r ?an te*nical skill4 ,nei!r ! ,egyptians nor any o!r peoples be=e ! ,middle ,ages h left any consi/5t evid5ce t !y 7 able to pi]ce gr\nd t w\ld n support itself above ! op5+ z w\ld firm rock4 ,9 ,egypt 7 e/abli%$ ! me?ods ( rock break+ t 7 to rema9 classical until ! fir/ use ( gun-p[d] bla/+ 9 ! #ag? c5tury :i* =m$ ! basis ( ! ensu+ te*nology ( m9+4 ,not)/&+ ! religi\s motives :i* inspir$ ! e>lie/ rock excavations1 m con/ant & univ]sal ?r\gh\t hi/ory has be5 ! inc5tive to obta9 ! useful & decorative m9]als hidd5 b5ea? ! e>?'s surface4 ,x 0 ! m9] :o develop$ ! me?ods introduc$ by ! e>ly civilizations to break rock away f ! prim>y mass1 & :o add$ ! ref9em5ts ( subt]ranean survey+ & v5tilat+1 all ( :i* 7 lat] to be assimilat$ into ! new art ( driv+ tunnels ( l>ge diamet]4 ,! connection is ! m evid5t f ! fact t tunnelm5 are /ill kn[n z m9]s4 ,,copp] ,,m9+1 ,b4,c4 ,!re=e1 ! fir/ model ( ! sequ5ce1 reflect+ elem5tal rock-break+ te*niques1 depicts a h>d-rock copp] m9e 7fig4 #a74 ,due to ! abs5ce ( specific in=mation ab\t su* works dur+ ! pre-,*ri/ian eras1 ?is model is bas$ on no p>ticul> p]iod or locale1 b repres5ts 9 a g5]al way1 a m9e 9 ! ,rio ,t9to area ( ,spa9 :]e copp] has be5 extract$ s9ce at lea/ #ajjj ,b4,c4 ,simil> work+s exi/$ 9 ! ,tirol z e>ly z ab\t #afjj ,b4,c4 ,two means ( break+ away ! rock are %[n3 to ! left is ! mo/ primitive ( all me?ods1 ! hamm] & *isel1 :i* require no fur!r description4 ,at ! "r side1 ! two figures are %[n utiliz+ ! fir/ rock-break+ me?od 9 :i* a =ce beyond t ( human muscles 0 employ$1 ! age-old fire-sett+ me?od4 ,! rock 0 ?or\ghly heat$ by a fi]ce fire built aga9/ its face & !n sudd5ly cool$ by da%+ wat] aga9/ x4 ,! !rmal %ock dis9tegrat$ ! rock or ore into bits easily removable by h&4 ,illu/ration3 ,figure #d4--;,,hoosac ,,tunnel4 ,bottom ( ! c5tral %aft %[+ elevator c> & rock skip2 pumps at f> "r4 ,9 ! c5t]1 ! top b5* is be+ drill$ by a s+le column-m\nt$ ,burleigh drill4 ,,mht model--#a_/b scale4 7,smi?sonian photo #dibfj-,n47 ,! practice ( ?is me?od bel[ gr\nd1 ( c\rse1 produc$ a fe>fully vitiat$ atmosph]e4 ,x is difficult to imag9e :e!r ! smoke1 ! /eam1 or ! toxic fumes f ! roa/+ ore 0 ! m di/ress+ to ! m9]s4 ,ev5 :5 p]=m$ by labor consid]$ m or less exp5dable1 ! me?od c\ld be employ$ only :]e !re 0 v5tilation ( "s sort3 natural *imneys & convection curr5ts 7 ! *ief s\rces ( air circulation4 ,despite ! drawbacks ( ! fire sy/em1 its simplicity & efficacy weigh$ s heavily 9 its favor t its hi/ory ( use is unbrok5 almo/ to ! pres5t day4 ,fire sett+ 0 ( greate/ importance dur+ ! ye>s ( int5sive m9+ 9 ,europe be=e ! adv5t ( explosive bla/+1 b its use 9 _m remote areas h>dly slack5$ until ! e>ly #bj? c5tury because ( its l[ co/ :5 comp>$ to p[d]4 ,= ?is same reason1 x did h limit$ application 9 actual tunnel "w until ab\t #aijj4 ,direct h&work ) pick1 *isel & hamm]1 & fire sett+ 7 ! pr9cipal means ( rock removal = c5turies4 ,al?\gh v>i\s w$g+ sy/ems 7 also 9 favor 9 "s situations1 _! importance 0 s slight t !y 7 n %[n 9 ! model4 ,,hoosac ,,tunnel ,x 0 possible 9 ! model s]ies1 )\t neglect+ any major advancem5t 9 ! art ( rock tunnel+1 to complete ! sequ5ce ( developm5t ) only a s+le additional model4 ,_m ( ! greate/ works ( civil eng9e]+ h be5 ^? conc]n$ directly ) transport1 & h5ce are ! product ( ! pres5t era1 beg9n+ 9 ! e>ly #ai? c5tury4 ,! developm5t ( ! anci5t arts ( r\te location1 bridge con/ruction1 & tunnel driv+ receiv$ a p[]ful /imulation aft] #ahjj "u ! impetus ( ! mod]n canal1 highway1 &1 especially1 ! railroad4 ,! ,hoosac ,tunnel1 driv5 ?r\gh ,hoosac ,m\nta9 9 ! v nor?we/ corn] ( ,massa*usetts betwe5 #ahea & #ahge1 0 ! fir/ major tunnel+ "w 9 ! ,unit$ ,/ates4 ,its importance is due n s mu* to ?is z to its be+ lit]ally ! f\nta9head ( mod]n rock-tunnel+ te*nology4 ,! rem>kable ?+ is t ! "w 0 begun us+ me?ods ( driv+ almo/ un*ang$ dur+ c5turies previ\s1 & 0 complet$ tw5ty ye>s lat] by te*niques :i* 71 = ! day1 almo/ totally me*aniz$4 ,! basic patt]n ( op]ation set at ,hoosac1 us+ pneumatic rock drills & effici5t explosives1 rema9s practically un*ang$ today4 ,! g5]al hi/ory ( ! ,hoosac project is s ?or\ghly record$ t ! briefe/ outl9e ( its political aspects w suffice "h4 ,hoosac ,m\nta9 0 ! *ief ob/acle 9 ! pa? ( a railroad project$ betwe5 ,gre5field1 ,massa*usetts1 & ,troy1 ,new ,york4 ,! l9e 0 laun*$ by a gr\p ( ,bo/on m]*ants to provide a direct r\te to ! rapidly develop+ ,we/1 9 competition ) ! coa/al r\tes via ,new ,york4 ,! only r\te economically reasonable includ$ a tunnel ( ne>ly five miles ?r\gh ! m\nta9--a l5g? absolutely )\t prec$5t1 & an imm5se und]tak+ 9 view ( ! relatively primitive rock-work+ me?ods !n available4 ,illu/ration3 ,figure #e4--;,,burleigh ,,rock ,,drill1 improv$ model ( ab\t #ahgj1 m\nt$ on frame = surface "w4 7,catalog & price li/3 ,! ,burleigh ,rock ,drill ,company1 #ahgf47 ,! bore's great l5g? & ! desire = rapid exploitation inspir$ innovation f ! outset ( ! "w4 ,! e>lie/ attempts at me*anization1 al?\gh ineffectual & )\t influ5ce on tunnel eng9e]+ until _m ye>s lat]1 are ( int]e/4 ,^! took ! =m ( sev]al exp]im5tal ma*9es ( ! full area type1 int5d$ to excavate ! entire face ( ! "w 9 a s+le op]ation by cutt+ "o or m conc5tric grooves 9 ! rock4 ,! rock rema9+ betwe5 ! grooves 0 to be bla/$ out4 ,! fir/ su* ma*9e te/$ succe$$ 9 bor+ a #bd-;foot diamet] op5+ = #aj feet be=e its total failure4 ,sev]al lat] ma*9es prov$ ( equal m]it4#b ,x 0 ! ,baltimore & ,ohio's em95t *ief eng9e]1 ,b5jam9 ,h4 ,latrobe1 :o 9 8 ,report on ! ,hoosac ,tunnel 7,baltimore1 ,oct4 #a1 #ahfb1 p4 #abe7 /at$ t su* app>atus conta9$ 9 its own /ructure ! elem5ts ( failure1 444 z !y require ! ma*9es to d too mu* & ! p[d] too little ( ! "w1 ?us contradict+ ! fundam5tal pr9ciples ^u :i* all labor-sav+ ma*9]y is fram$ 444 ,i c\ld only look ^u x z a misapplication ( me*anical g5ius4 ,illu/ration3 ,figure #f4--;,,hoosac ,,tunnel4 ,fla%-p[d] photograph ( ,burleigh drills at ! work+ face4 7,photo c\rtesy ( ,/ate ,libr>y1 ,commonweal? ( ,massa*usetts47 ,latrobe /at$ ! basic philosophy ( rock-tunnel "w4 ,no me*anical ag5t has ev] be5 able to improve ^u ! effici5cy ( explosives = ! %att]+ ( rock4 ,= ?is reason1 ! logical application ( ma*9]y to tunnel+ 0 n 9 replac+ or alt]+ ! fundam5tal process itself1 b 9 enabl+ x to be conduct$ ) great] spe$ by me*anically drill+ ! bla/+ holes to receive ! explosive4 ,actual "w on ! ,hoosac ,tunnel began at bo? ends ( ! tunnel 9 ab\t #ahed1 b )\t mu* useful effect until #aheh :5 a contract 0 let to ! r5[n$ civil eng9e] & railroad build]1 ,h]man ,haupt ( ,philadelphia4 ,haupt imm$iately resum$ inve/igations ( improv$ tunnel+ me?ods1 bo? full-area ma*9es & me*anical rock drills4 ,at ?is "t me*anical rock-drill te*nology 0 9 a /ate beyond1 b n f> beyond1 initial exp]im5tation4 ,!re exi/$ "o workable ,am]ican ma*9e1 ! ,f[le drill1 inv5t$ 9 #ahea4 ,x 0 /eam-driv51 & _h be5 us$ 9 qu>ry "w1 al?\gh app>5tly n to any comm]cial ext5t4 ,h[ev]1 x 0 f> too l>ge & cumb]some to f9d any possible application 9 tunnel+4 ,nev]!less1 x conta9$ 9 its op]at+ pr9ciple1 ! se$ ( a practical rock drill 9 t ! drill rod 0 atta*$ directly to & reciprocat$ by a d\ble-act+ /eam pi/on4 ,a po9t ( great importance 0 ! indep5d5ce ( its op]ation on gravity1 p]mitt+ drill+ 9 any direction4 ,:ile exp]im5t+1 ,haupt drove ! "w onw>d by ! classical me?ods1 %[n 9 ! left-h& section ( ! model 7fig4 #b74 ,at ! f> "r an advance head+ or adit is be+ =m$ by pick & hamm] "w2 ?is is !n deep5$ into a top head+ ) en\gh height to p]mit hamm] drill+1 actually ! basic tunnel+ op]ation4 ,a team is %[n d\ble jack+1 i4e41 us+ two-h&$ hamm]s1 ! /eel held by a ?ird man4 ,?is 0 ! mo/ effici5t ( ! sev]al h&-drill+ me?ods4 ,! top-head+ plan 0 foll[$ s t ! bulk ( ! rock c\ld be remov$ 9 ! =m ( a bottom b5*1 & ! majority ( drill+ w\ld be d[nw>d1 obvi\sly ! mo/ effective direction4 ,bla/+ 0 ) black p[d] & its comm]cial v>iants4 ,"s lib]ty 0 tak5 9 depict+ ^! /eps s t bo? op]ations might be %[n )9 ! scope ( ! model3 9 practice ! head+ 0 kept betwe5 #djj & #fjj feet 9 advance ( ! b5* s t head+ bla/s w\ld n int]f]e ) ! b5* "w4 ,! b5* c>riage simply facilitat$ h&l+ ( ! bla/$ rock4 ,x 0 roll$ back dur+ bla/s4 ,illu/ration3 ,figure #g4--;,,hoosac ,,tunnel4 ,,gr\p ,,( ,,m9]s desc5d+ ! we/ %aft ) a ,burleigh drill4 7,photo c\rtesy ( ,/ate ,libr>y1 ,commonweal? ( ,massa*usetts47 ,! exp]im5ts conduct$ by ,haupt ) ma*9e drills produc$ no imm$iate useful results4 ,a drill design$ by ,haupt & 8 associate1 ,/u>t ,gwynn1 9 #aheh bor$ h>d granite at ! rate ( #e_/h in* p] m9ute1 b 0 n sub/antial en\gh to be> up 9 s]vice4 ,haupt left ! "w 9 #ahfa1 victim ( int5se political pressures & totally unju/ accusations ( corruption & mismanagem5t4 ,! "w 0 susp5d$ until tak5 ov] by a /ate commission 9 #ahfb4 ,despite frightful ineptitude & v real corruption1 ?is p]iod 0 exce$+ly important 9 ! long hi/ory bo? ( ,hoosac ,tunnel & ( rock tunnel+ 9 g5]al4 ,! m]ely r\t9e criticism ( ! project _h by ?is "t become viol5t due to ! inord9ate l5g? ( "t already elaps$ & ! imm5se co/1 comp>$ to ! small portion ( "w complet$4 ,?is s]v$ to g5]ate 9 ! commission a /rong s5se ( urg5cy to hurry ! project along4 ,*>les ,s4 ,/orr[1 a compet5t eng9e]1 0 s5t to ,europe to report on ! progress ( tunnel+ !re1 & 9 p>ticul> on me*anization at ! ,mont ,c5is ,tunnel !n "u con/ruction betwe5 ,france & ,italy4 ,g]ma9 ,sommeill]1 its *ief eng9e]1 _h1 aft] exp]im5tation simil> to ,haupt's1 inv5t$ a reasonably effici5t drill+ ma*9e :i* _h gone into s]vice at ,mont ,c5is 9 ,m>* #ahfa4 ,x 0 a di/9ct improvem5t ov] h& drill+1 almo/ d\bl+ ! drill+ rate1 b 0 complex & highly unreliable4 ,two hundr$ drills 7 requir$ to keep #af drills at "w4 ,b ! vital po9t 9 ?is 0 ! fact t ,sommeill] drove 8 drills n ) /eam1 b air1 compress$ at ! tunnel portals & pip$ to ! "w face4 ,x 0 ?is s+le factor1 "o ( application r ?an inv5tion1 t made ! me*anical drill feasible = tunnel+4 ,all previ\s ef=t 9 ! field ( ma*9e drill+1 on bo? sides ( ! ,atlantic1 _h be5 direct$ t[>d /eam z ! motive p[]4 ,9 deep tunnels1 ) v5tilation already an inh]5t problem1 ! exhau/ ( a /eam drill into ! atmosph]e 0 inadmissible4 ,fur!r1 /eam c\ld n be pip$ ov] great di/ances due to s]i\s losses ( en]gy f radiation ( heat1 & cond5sation4 ,/eam g5]ation )9 ! tunnel itself 0 obvi\sly out ( ! "q4 ,x 0 ! comb9ation ( a practical drill1 & ! p>allel inv5tion by ,sommeill] ( a practical air compressor t result$ 9 ! fir/ workable application ( ma*9e rock drill+ to tunnel+4 ,illu/ration3 ,figures #h #i4--;,,hoosac ,,tunnel4 ,,contempor>y ,,engrav+s4 ,z su* l>ge g5]al areas c\ld n be suffici5tly illum9at$ = photography1 ! ,museum model 0 bas$ prim>ily on arti/s' v]sions ( ! "w4 7,sci5ce ,record1 #ahgb2 ,leslie's ,weekly1 #ahgc47 ,! ,sommeill] drills greatly impress$ ,/orr[1 & 8 report ( ,novemb] #ahfb /rongly favor$ _! adoption at ,hoosac4 ,x is curi\s h[ev]1 t n a s+le "o 0 br\ght to ! ,u4,s41 ev5 on trial4 ,/orr[ does speak ( ,sommeill]'s int5t to keep ! details ( ! ma*9e to himself until x _h be5 fur!r improv$1 ) a view to its ev5tual exploitation4 ,! fact is1 t al?\gh workable1 ! ,sommeill] drill prov$ to be a dead end 9 rock-drill developm5t because ( its _m basic defici5cies4 ,x did ex]t ! indirect influ5ce ( inspiration :i*1 c\pl$ ) a press+ ne$ = ha/e1 l$ to r5ew$ trials ( drill+ ma*9]y at ,hoosac4 ,?omas ,doane1 *ief eng9e] "u ! /ate commission1 c>ri$ ?is program =? ) int5sity1 seek+ & enc\rag+ inv5tors1 & himself work+ on ! problem4 ,! patt]n ( ! ,sommeill] drill 0 g5]ally foll[$2 t is1 ! drill 0 design$ z a sep>ate1 relatively light me*anical elem5t1 adapt$ = transportation by sev]al m9]s1 & atta*able to a movable frame or c>riage dur+ op]ation4 ,air 0 ( c\rse ! presum$ p[]4 ,to be effective1 x 0 necess>y t a drill automatically fe$ ! drill rod z ! hole deep5$1 & also rotate ! rod automatically to ma9ta9 a r\nd1 smoo? hole4 ,extreme durability 0 ess5tial1 & usually prov$ ! s\rce ( a ma*9e's failure4 ,! comb9ation ( ^! *>act]i/ics into a ma*9e capable ( driv+ ! drill rod into ! rock ) great =ce1 p]haps five times p] second1 0 a sev]e te/ ( +5uity & mat]ials4 ,doane 9 #ahfd _h ?ree diff]5t exp]im5tal drills 9 h&1 z well z v>i\s /eam & wat]-p[]$ compressors4 ,success f9ally came 9 #ahfe ) ! inv5tion ( a drill by ,*>les ,burleigh1 a me*anical eng9e] at ! well-kn[n ,putnam ,ma*9e ,works ( ,fit*burg1 ,massa*usetts4 ,! drills 7 fir/ appli$ 9 ! ea/ head+ 9 ,june ( #ahff4 ,al?\gh work+ well1 _! initial success 0 limit$ by lack ( reliability & a result+ high exp5se = repairs4 ,!y 7 describ$ z hav+ sev]al weake/ po9ts4 ,9 ,novemb]1 ^! drills 7 replac$ by an improv$ ,burleigh drill :i* 0 us$ ) total success to ! end ( ! "w4 ,! era ( mod]n rock tunnel+ 0 ?us laun*$ by ,sommeill]'s insight 9 initially apply+ pneumatic p[] to a ma*9e drill1 by ,doane's p]si/5ce 9 se>*+ = a ?or\ghly practical drill1 & by ,burleigh's me*anical tal5t 9 produc+ "o4 ,! desp]ate ne$ to complete ! ,hoosac ,tunnel may reasonably be consid]$ ! greate/ s+le spur to ! developm5t ( a successful drill4 ,! significance ( ?is inv5tion 0 f> rea*+4 ,burleigh's 0 ! fir/ practical me*anical rock drill 9 ,am]ica &1 9 view ( its dep5dability1 effici5cy1 & simplicity :5 comp>$ to ! ,sommeill] drill1 p]haps 9 ! _w4 ,! ,burleigh drill a*iev$ success almo/ imm$iately4 ,x 0 plac$ 9 production by ,putnam = ! ,burleigh ,rock ,drill ,company be=e completion ( ,hoosac 9 #ahgf1 & its use spread ?r\gh\t ! we/]n m9+ regions & o!r tunnel works4 ,= a major inv5tion1 its adoption 01 9 relative t]ms1 in/antane\s4 ,x 0 ! prototype ( all succe$+ pi/on-type drills1 :i* came to be kn[n g5]ically z burleighs1 reg>dless ( manufacture4 ,walt] ,%anley1 ! ,canadian contractor :o ultimately complet$ ! ,hoosac1 report$ 9 #ahgj1 aft] ! drills _h be5 9 s]vice = a suffici5t "t t ! te*niques = _! mo/ effici5t use 7 fully und]/ood & effectively appli$1 t ! ,burleigh drills sav$ ab\t half ! drill+ co/s ov] h& drill+4 ,! p]-in* co/ ( ma*9e drill+ av]ag$ #e4e c5ts1 all inclusive1 vs4 #aa4b c5ts = h&work4 ,! m important po9t1 t ( spe$1 is %[n by ! reports ( av]age mon?ly progress ( ! tunnel itself1 be=e & aft] use ( ! air drills4 ,ye> ,av]age mon?ly progress 9 feet #ahfe #ee #ahff #dh #ahfg #ii #ahfh -- #ahfi #ach #ahgj #abf #ahga #ade #ahgb #abd ,illu/ration3 ,figure #aj4--,,tr9itroglyc]9e ,,bla/ at ,hoosac ,tunnel4 7,leslie's ,weekly1 #ahgc47 ,! "r portion ( ! model 7fig4 #c7 repres5ts ! work+s dur+ ! f9al p]iod4 ,! bottom head+ sy/em 0 g5]ally us$ aft] ! ,burleigh drills _h be5 introduc$4 ,f\r to six drills 7 m\nt$ on a c>riage design$ by ,doane4 ,^! drove ! holes = ! fir/ bla/ 9 ! c5t] ( ! head+ 9 ab\t six h\rs4 ,! full wid? ( ! head+1 ! #bd-;foot wid? ( ! tunnel1 0 !n drill$ & bla/$ out 9 two m /ages4 ,z 9 ! e>ly section1 ! b5*es to ! re> 7 lat] remov$ to ! full-tunnel height ( ab\t #bj feet4 ,?is op]ation is %[n by a s+le drill 7fig4 #d7 m\nt$ on a screw column4 ,?ree #h-;h\r %ifts c>ri$ ! "w =w>d3 drill+ occupi$ half ! "t & half 0 sp5t 9 runn+ ! c>riage back1 bla/+1 & muck+ 7cle>+ ! brok5 rock74 ,illu/ration3 ,figure #aa4--;,,hoosac ,,tunnel survey crew at eng9e]+ (fice4 ,! highe/ accuracy ( ! abovegr\nd & und]gr\nd survey "w 0 requir$ to insure prop] v]tical & horizontal alignm5t & meet+ ( ! sev]al sep>ately driv5 sections4 7,photo c\rtesy ( ,/ate ,libr>y1 ,commonweal? ( ,massa*usetts47 ,! tunnel's #ajbh-;foot c5tral %aft1 complet$ "u ! ,%anley contract 9 #ahgj to provide two additional "w faces z well z a v5tilation %aft is %[n at ! f> "r side ( ?is half ( ! model4 ,complet$ s ne> ! end ( ! project1 only #ae p]c5t ( ! tunnel 0 driv5 f ! %aft4 ,! enorm\s increase 9 rate ( progress 0 n due entirely to ma*9e drill+4 ,f ! outset ( 8 jurisdiction1 ,doane und]took exp]im5ts ) explosives z well z drills1 seek+ an ag5t m effective ?an black p[d]4 ,9 ?is case1 ! ne$ = spe$ 0 n ! sole /imulus4 ,z ! ea/ & we/ head+s advanc$ fur!r & fur!r f ! portals1 ! problem ( v5tilation grew m acute1 & x became increas+ly difficult to exhau/ ! toxic fumes produc$ by ! black p[d] bla/s4 ,9 #ahff1 ,doane import$ f ,europe a sample ( tr9itroglyc]9e1 ! liquid explosive newly introduc$ by ,nobel1 kn[n 9 ,europe z glono9 oil & 9 ! ,unit$ ,/ates z nitroglyc]9e4 ,x already _h acquir$ a fe>some reputation f its t5d5cy to decompose ) heat & age & to explode ) or )\t ! slighte/ provocation4 ,nev]!less1 its trem5d\s p[] & *>act]i/ic ( almo/ complete smokelessness l$ ,doane to employ ! *emi/ ,george ,w4 ,m[bray1 :o _h bla/$ = ,drake 9 ! ,p5nsylvania oil fields1 to develop te*niques = ! bulk manufacture ( ! new ag5t & = its safe employm5t 9 ! tunnel4 ,m[bray e/abli%$ a works on ! m\nta9 & %ortly develop$ a completely new bla/+ practice bas$ on ! explosive4 ,its /ability 0 greatly increas$ by ma9ta9+ absolute purity 9 ! manufactur+ process4 ,freez+ ! liquid to r$uce its s5sitivity dur+ transport to ! head+s1 & extreme caution 9 its h&l+ fur!r r$uc$ ! haz>d ( its use4 ,at ! head+1 ! liquid 0 p\r$ into cyl9drical c>tridges = placem5t 9 ! holes4 ,z ) ! ,burleigh drill1 ! g5]al adoption ( nitroglyc]9e 0 imm$iate once its qualities _h be5 demon/rat$4 ,! effect on ! "w 0 notable4 ,its explosive *>act]i/ics p]mitt$ few] bla/ holes ov] a giv5 frontal area ( work+ face1 & at ! same "t x 0 capable ( effectively bl[+ f a deep] drill hole1 #db in*es aga9/ #cj in*es = black p[d]1 s t "u ideal conditions #dj p]c5t m tunnel l5g? 0 advanc$ p] cycle ( op]ations4 ,a new fuse & a sy/em ( electric ignition 7 develop$ :i* p]mitt$ simultane\s detonation & result$ 9 a degree ( effectiv5ess impossible ) ! p[d] tra9 & cord fus+ us$ ) ! black p[d]4 ,ov] a million p\nds ( nitroglyc]9e 7 produc$ by ,m[bray betwe5 #ahff & completion ( ! tunnel4 ,illu/ration3 ,figure #ab4--,,works ,,at ,,! ,,c5tral ,,%aft1 ,,hoosac ,,tunnel1 = hoi/+1 pump+ & air compress+ ma*9]y1 & g5]al repair1 #ahga4 7,photo c\rtesy ( ,/ate ,libr>y1 ,commonweal? ( ,massa*usetts47 ,illu/ration3 ,figure #ac4--;,,hoosac ,,tunnel4 ,,air-,,compressor ,,build+ on ,hoosac ,riv] ne> ,nor? ,adams4 ,! compressors 7 driv5 p>tially by wat]p[]1 d]iv$ f ! riv]4 7,photo c\rtesy ( ,/ate ,libr>y1 ,commonweal? ( ,massa*usetts47 ,illu/ration3 ,figure #ad4--,,we/ ,,portal ,,( ,,hoosac ,,tunnel be=e completion1 #ahfh1 %[+ six r+s ( l9+ brick4 7,photo c\rtesy ( ,/ate ,libr>y1 ,commonweal? ( ,massa*usetts47 ,:5 ! ,%anleys took ! "w ov] 9 #ahfh1 foll[+ political difficulties att5d+ op]ation by ! ,/ate1 ! p]iod ( exp]im5tation 0 ov]4 ,! tunnel 0 be+ advanc$ by totally mod]n me?ods1 & to ! pres5t day ! ov]all concepts h rema9$ fundam5tally unalt]$3 ! ,burleigh pi/on drill has be5 replac$ by ! light] hamm] drill2 ! ,doane drill c>riage by ! m flexible jumbo2 nitroglyc]9e by its m /able desc5dant dynamite & its alt]natives2 & /atic-electric bla/+ ma*9es by m dep5dable magnetoelectric4 ,b ^! are all 9 ! nature ( improvem5ts1 n innovations4 ,unlike ! prec$+ model1 !re 0 good docum5tation = ?is "o4 ,also1 ! ,hoosac 0 app>5tly ! fir/ ,am]ican tunnel to be well record$ photographically4 ,e>ly fla%light views exi/ ( ! drills work+ at ! head+ 7fig4 #f7 z well z ( ! portals1 ! w9d+ & pump+ works at ! c5tral %aft1 & mu* ( ! ma*9]y & associat$ aspects ( ! project4 ,^! & copies ( draw+s ( mu* ( ,doane's exp]im5tal app>atus1 a r>e te*nological record1 are pres]v$ at ! ,massa*usetts ,/ate ,libr>y4 ,s(t-,gr\nd ,tunnel+ ,s great is ! diff]5ce betwe5 h>d-rock & s(t-gr\nd tunnel+ t !y con/itute two almo/ sep>ate bran*es ( ! field4 ,9 p5etrat+ gr\nd lack+ ! firmness or cohesion to support itself above an op5+1 ! m9]'s *ief conc]n is n t ( remov+ ! mat]ial1 b ( prev5t+ its collapse into 8 excavation4 ,! primitive me?ods dep5d+ ^u brute /r5g? & direct application ( fire & human =ce 7 suitable = assault on rock1 b lack$ ! artifice ne$$ = delv+ into less /able mat]ial4 ,roman eng9e]s 7 accompli%$ 9 spann+ subt]ranean ways ) masonry ar*es1 b app>5tly mo/ ( _! "w 0 done by cut-&-cov] me?ods r ?an by actual m9+4 ,n until ! ,middle ,ages did ! skill ( effectively work+ op5+s 9 s(t gr\nd develop1 & n until ! ,r5aissance 0 ?is developm5t s consi/5tly successful t x c\ld be consid]$ a sci5ce4 ,,r5aissance ,,m9+ ,f ! e>lie/ p]iods ( rock work+1 ! que/ = m9]als & metals 0 ! prim>y =ce t drove m5 und]gr\nd4 ,x 0 ! te*nology ( m9+1 ! product ( sl[ evolution ov] ! c5turies1 t became ! te*nology ( ! e>ly tunnel1 ) no significant modification except 9 size ( work+s4 ,e aspect ( #af? c5tury m9+ is def9itively detail$ 9 ,georgius ,agricola's rem>kable ,de re ,metallica1 fir/ publi%$ 9 ,basel 9 #aeef4 ,dur+ its "t ( active influ5ce1 :i* ext5d$ = two c5turies1 x s]v$ z ! au?oritative "w on ! subject4 ,x rema9s today an unp>allel$ e>ly record ( an entire bran* ( te*nology4 ,! sup]b woodcuts ( m9e work+s & tools 9 !mselves con/itute a precise description ( ! te*niques ( ! p]iod1 & provid$ an ideal s\rce ( in=mation ^u :i* to base ! fir/ model 9 ! s(t-gr\nd s]ies4 ,illu/ration3 ,figure #ae4--;,,c5t]+ ,,= ,,placem5t ,,( ,,f9i%$ ,,/onework at we/ portal1 #ahgd4 ,at top-"r are ! %$s :]e ! l9+ brick 0 produc$4 7,photo c\rtesy ( ,/ate ,libr>y1 ,commonweal? ( ,massa*usetts47 ,! model1 repres5t+ a typical ,european m9e1 demon/rates ! e>ly use ( timb] frames or sets to support ! s(t mat]ial ( ! walls & ro(4 ,9 areas ( only mod]ate in/ability1 ! sets alone 7 suffici5t to c\nt]act ! e>? pressure1 & 7 spac$ accord+ to ! degree ( support requir$4 ,9 m extreme conditions1 a solid lagg+ ( small poles or bo>ds 0 set outside ! frames1 z %[n 9 ! model1 to provide absolute support ( ! gr\nd4 ,details ( ! fram+1 ! w9dlass1 & all tools & appliances 7 suppli$ by ,agricola1 ) no ne$ = int]pretation or int]polation4 ,! basic fram+ patt]n ( sill1 side po/s & cap piece1 all mortic$ toge!r1 ) lagg+ us$ :]e ne$$1 0 translat$ unalt]$ into tunnel+ practice1 p>ticul>ly 9 small exploratory drifts4 ,x rema9$ 9 ?is application until well into ! #bj? c5tury4 ,! pressure ex]t$ ^u tunnels ( l>ge area 0 c\nt]$ dur+ con/ruction by timb]+ sy/ems ( great] elaboration1 evolv$ f ! basic "o4 ,by ! "t t tunnels ( section l>ge en\gh to accommodate canals & railways 7 be+ und]tak5 z matt]-(-c\rse civil eng9e]+ works1 a s]ies ( nationally di/+ui%able sy/ems _h em]g$1 ea* possess+ *>act]i/ic po9ts ( favor & fault4 ,z might be suspect$1 ! ,engli% sy/em ( tunnel timb]+1 = in/ance1 0 r>ely appli$ on ! ,cont95t1 nor 7 ! ,g]man1 ,au/rian or ,belgian sy/ems normally se5 9 ,great ,brita94 ,all 7 us$ at "o "t or ano!r 9 ?is c\ntry1 until ! ,am]ican sy/em 0 introduc$ 9 ab\t #ahee4 ,:ile ! timb]+ commonly rema9$ 9 place 9 m9es1 x w\ld be foll[$ up by p]man5t masonry ar*+ & l9+ 9 tunnel "w4 ,ov]head 9 ! museum ,hall ( ,civil ,eng9e]+ are frames repres5t+ ! ,engli%1 ,au/rian & ,am]ican sy/ems4 ,ne>by1 a s]ies ( small relief models 7fig4 #ai7 is us$ to %[ ! sequ5ce ( enl>gem5t 9 a s(t-gr\nd railroad tunnel ( ab\t #ahee1 us+ ! ,au/rian sy/em4 ,tempor>y timb] support ( tunnels fell f use gradually aft] ! adv5t ( %ield tunnel+ 9 conjunction ) ca/-iron l9+4 ,?is =m$ a p]fect support imm$iately beh9d ! %ield1 z well z ! p]man5t l9+ ( ! tunnel4 ,,brunel',s ,,?ames ,,tunnel ,! int]ior surfaces ( tunnels ?r\gh gr\nd m]ely un/able are am5able to support by v>i\s sy/ems ( timb]+ & ar*+4 ,?is becomes less true z ! fluidity ( ! gr\nd increases4 ,! s(t mat]ial :i* normally comprises ! b$s ( riv]s c approa* an almo/ liquid condition result+ 9 a hydraulic head f ! ov]be>+ wat] suffici5t to prev5t ! driv+ ( ev5 ! mo/ c>efully work$ drift1 support$ by simple timb]+4 ,! basic defect ( ! timb]+ sy/ems us$ 9 m9+ & tunnel+ 0 t !re 0 inevitably a c]ta9 am\nt ( ! face or ceil+ unsupport$ j previ\s to sett+ a frame1 or plac+ ov] x ! necess>y section ( lagg+4 ,9 m9e "w1 runny soil c\ld1 & did1 break ?r\gh su* gaps1 fill+ ! work+4 ,= ?is reason1 !re 7 no s]i\s attempts made be=e #ahbe to drive subaque\s tunnels4 ,9 t ye>1 "w 0 />t$ on a tunnel "u ! ,?ames betwe5 ! ,ro!rhi! & ,wapp+ sections ( ,london1 "u guidance ( ! already fam\s eng9e] ,m>c ,isamb>d ,brunel 7#agfi-ahdi71 fa!r ( ,i4 ,k4 ,brunel4 ,! und]tak+ is ( great int]e/ 9 t ,brunel employ$ an entirely novel app>atus ( 8 own inv5tion to provide cont9u\s & reliable support ( ! s(t wat]-be>+ clay :i* =m$ ! riv]b$4 ,by means ( ?is %ield1 ,brunel 0 able to drive ! _w's fir/ subaque\s tunnel4#c ,illu/ration3 ,figure #af4--,,we/ ,,portal ,,^u ,,completion1 #ahgf4 7,photo c\rtesy ( ,new-,york ,hi/orical ,society47 ,! %ield 0 ( ca/-iron1 rectangul> 9 elevation1 & 0 propell$ =w>d by jackscrews4 ,%elves at top1 bottom1 & sides support$ ! tunnel ro(1 floor1 & walls until ! p]man5t brick l9+ 0 plac$4 ,! work+ face1 ! critical area1 0 support$ by a l>ge numb] ( small brea/+ bo>ds1 held aga9/ ! gr\nd by small individual screws be>+ aga9/ ! %ield framework4 ,! %ield itself 0 =m$ ( #ab sep>ate frames1 ea* ( :i* c\ld be advanc$ indep5d5tly ( ! o!rs4 ,! height 0 #bb feet #c in*es3 ! wid? #cg feet #f in*es4 ,! progress 0 piecemeal4 ,9 op]ation ! m9]s w\ld remove "o brea/+ bo>d at a "t1 excavate 9 front ( x1 & !n replace x 9 ! advanc$ position--ab\t #f in*es =w>d4 ,?is 0 repeat$ ) ! next bo>d above or bel[1 & ! sequ5ce cont9u$ until ! gr\nd = ! entire height ( "o ( ! #ab sections _h be5 remov$4 ,! bo>d screws = t section 7 %ift$ to be> on ! adjac5t frames1 reliev+ ! frame ( longitud9al pressure4 ,x c\ld !n be screw$ =w>d by ! am\nt ( advance1 ! screws be>+ to ! re> on ! complet$ masonry4 ,?us1 /ep by /ep ! tunnel progress$ sl[ly1 ! greate/ weekly advance be+ #ad feet4 ,9 ! left-h& portion ( ! model is ! %aft sunk to beg9 op]ations2 "h also is %[n ! bucket hoi/ = remov+ ! spoil4 ,! ,v-type /eam eng9e p[]+ ! hoi/ 0 design$ by ,brunel4 ,at ! "r ( ! ma9 model is an enl>g$ detail ( ! %ield1 actually an improv$ v]sion built 9 #ahce4 ,! "w cont9u$ despite setbacks ( e sort4 ,! f9ancial ones ne$ no rec\nt+ "h4 ,te*nically1 al?\gh ! %ield pr9ciple prov$ workable1 ! support af=d$ 0 n infallible4 ,f\r or five times ! riv] broke ?r\gh ! ?9 cov] ( silt & flood$ ! work+s1 despite ! utmo/ caution 9 excavat+4 ,:5 ?is occurr$1 masses ( clay1 s&bags1 & mats 7 dump$ ov] ! op5+ 9 ! riv]b$ to seal x1 & ! tunnel pump$ out4 ,i4 ,k4 ,brunel act$ z sup]9t5d5t & ne>ly lo/ 8 life on a numb] ( occasions4 ,aft] sev]al susp5sions ( "w result+ f )drawal or exhau/ion ( support1 "o la/+ sev5 ye>s1 ! "w 0 complet$ 9 #ahdc4 ,despite ! fact t ,brunel _h1 = ! fir/ "t1 demon/rat$ a practical me?od = tunnel+ 9 firm & wat]-be>+ gr\nd1 ! enorm\s co/ ( ! "w & ! almo/ ov]:elm+ problems enc\nt]$ _h a disc\rag+ effect r ?an o!rwise4 ,n = ano!r qu>t] ( a c5tury 0 a simil> project und]tak54 ,! ,?ames ,tunnel 0 us$ = foot & light highway traffic until ab\t #ahgj :5 x 0 incorporat$ into ! ,london ,und]gr\nd railway sy/em1 :i* x cont9ues to s]ve today4 ,! ro($-ov] top sections ( ! two %afts may /ill be se5 f ! riv]4 ,a numb] ( contempor>y popul> acc\nts ( ! tunnel exi/1 b "o ( ! mo/ ?or\gh & int]e/+ expositions on a s+le tunnel "w ( any p]iod is ,h5ry ,law's ,a ,memoir ( ! ,?ames ,tunnel1 publi%$ 9 #ahde-ahdf by ,john ,weale4 ,law1 an em95t civil eng9e]1 cov]s ! "w 9 incr$ible detail f its inception until ! major susp5sion 9 late #ahbh :5 slightly m ?an half complet$4 ,! mo/ valuable aspect ( 8 record is a s]ies ( plates ( eng9e]+ draw+s ( ! %ield & its compon5ts1 :i*1 s f> z is kn[n1 exi/ n[h]e else4 ,^! =m$ ! basis ( ! enl>g$ section ( ! %ield1 %[n to ! "r ( ! model ( ! tunnel itself4 ,a v]tical section ?r\gh ! %ield is reproduc$ "h f ,law = comp>ison ) ! model 7figs4 #ba & #bc74 ,illu/ration3 ,figure #ag4--,,s(t-,,gr\nd ,,tunnel+4 ,! support ( walls & ro( ( m9e %aft by simple timb]+2 #af? c5tury4 ,,mht model--#c_/d scale4 7,smi?sonian photo #dibfj-;,j47 ,illu/ration3 ,figure #ah4--,,s(t-,,gr\nd ,,tunnel+4 ,! model ( a #af? c5tury m9e 9 ! ,museum ( ,hi/ory & ,te*nology 0 con/ruct$ f illu/rations 9 su* works z ,g4 ,e4 von ,loehneyss' ,b]i*t vom ,b]gw]ck1 #afij1 z well z ! bett] kn[n ones f ,de re ,metallica4 ,illu/ration3 ,figure #ai4--,,! ,,successive ,,/ages 9 ! enl>gem5t ( a mid-#ai? c5tury railroad tunnel1 us+ ! ,au/rian sy/em ( timb]+4 ,,mht model4 ,illu/ration3 ,figure #bj4--,m4 ,i4 ,,brunel',s ,,?ames ,,tunnel1 #ahbe-ahdc1 ! fir/ driv5 b5ea? a body ( wat]4 ,,mht model--#a_/d scale4 7,smi?sonian photo #dibfj-;,f47 ,,! ,,t[] ,,subway ,v>i\s inv5tors attempt$ to improve ^u ! ,brunel %ield1 aw>e ( ! fundam5tal s\ndness ( ! %ield pr9ciple4 ,almo/ all bypass$ ! rectangul> sectional con/ruction us$ 9 ! ,?ames ,tunnel1 & took z a />t+ po9t a sectional %ield ( circul> cross section1 advanc$ by ,brunel 9 8 orig9al pat5t ( #ahah4 ,james ,h5ry ,grea!ad 7#ahdd-ahif71 rightfully call$ ! fa!r ( mod]n subaque\s tunnel+1 surmis$ 9 lat] ye>s t ,brunel _h *os5 a rectangul> configuration = actual use1 z "o bett] adapt$ to ! sectional type ( %ield4 ,! ,engli% civil eng9e]1 ,pet] ,w4 ,b>l[1 9 #ahfd & #ahfh pat5t$ a circul> %ield1 ( "o piece1 :i* 0 ! basis ( "o us$ by him 9 con/ruct+ a small subway ( #acej feet b5ea? ! ,?ames 9 #ahfi1 ! fir/ "w to foll[ ! lead ( ,brunel4 ,grea!ad1 act+ z ,b>l['s contractor1 0 ! design] ( ! %ield actually us$ 9 ! "w1 b x 0 obvi\sly inspir$ by ,b>l['s pat5ts4 ,! r$uction ( ! multiplicity ( p>ts 9 ! ,brunel %ield to a s+le rigid unit 0 ( imm5se advantage & an advance p]haps equal to ! %ield concept ( tunnel+ itself4 ,! ,b>l[-,grea!ad %ield 0 l ! cap ( a telescope ) a %>p5$ circul> r+ on ! front to assi/ 9 p5etrat+ ! gr\nd4 ,! diaphragm function$1 z did ,brunel's brea/+ bo>ds1 to resi/ ! longitud9al e>? pressure ( ! face1 & ! cyl9drical portion beh9d ! diaphragm bore ! radial pressure ( ro( & walls4 ,"h also = ! fir/ "t1 a p]man5t l9+ =m$ ( ca/-iron segm5ts 0 us$1 a second major advancem5t 9 s(t-gr\nd tunnel+ practice4 ,n only c\ld ! segm5ts be plac$ & bolt$ toge!r f> m rapidly ?an masonry l9+ c\ld be laid up1 b unlike ! gre5 masonry1 !y c\ld imm$iately be> ! full =ce ( ! %ield-propell+ screws4 ,b>l[1 capitaliz+ on ,brunel's error 9 burr[+ s close to ! riv]b$1 ma9ta9$ an av]age cov] ( #cj feet ov] ! tunnel1 driv+ ?r\gh a solid /ratum ( firm ,london clay :i* 0 virtually imp]vi\s to wat]4 ,z ! result ( ?is1 comb9$ ) ! advantages ( ! solid %ield & ! rapidly plac$ iron l9+1 ! "w mov$ =w>d at a pace & ) a facility 9 />tl+ contra/ to t ( ! ,?ames ,tunnel1 al?\gh 9 fairness x mu/ be recall$ t ! face area 0 f> less4 ,! clay 0 f\nd suffici5tly s\nd t x c\ld be readily excavat$ )\t ! support ( ! diaphragm1 & normally ?ree m9]s work$ 9 front ( ! %ield1 digg+ out ! clay & pass+ x back ?r\gh a doorway 9 ! plate4 ,?is c\ld be clos$ 9 case ( a sudd5 settlem5t or break 94 ,foll[+ excavation1 ! %ield 0 advanc$ #ah in*es into ! excavat$ area by means ( #f screws1 & a r+ ( l9+ segm5ts #ah in*es 9 l5g? bolt$ to ! previ\s r+ "u cov] ( ! ov]lapp+ re> skirt ( ! %ield4 ,! small annul> space left betwe5 ! outside ( ! l9+ & ! clay by ! ?ickness & cle>ance ( ! skirt--ab\t an in*--0 fill$ ) ?9 cem5t gr\t4 ,! tunnel 0 advanc$ #ah in*es dur+ ea* #h-;h\r %ift4 ,! "w cont9u$ ar\nd ! clock1 & ! #ijj-;foot riv] section 0 complet$ 9 only #ad weeks4#d ,! entire "w 0 complet$ almo/ )\t incid5t 9 j "u a ye>1 a rem>kable p]=mance = ! _w's second subaque\s tunnel4 ,illu/ration3 ,figure #ba4--;,,enl>g$ ,,detail ( ,brunel's tunnel+ %ield1 v]tical section4 ,! fir/ two & "p ( ! ?ird ( ! twelve frames are %[n4 ,to ! left is ! tunnel's complet$ brick l9+ & to ! "r1 ! individual brea/+ bo>ds & screws = support+ ! face4 ,! propell+ screws are se5 at top & bottom1 be>+ aga9/ ! l9+4 ,?ree m9]s work$ 9 ea* frame1 "o above ! o!r4 ,,mht model--#c_/d scale4 7,smi?sonian photo #dibfj-;,g47 ,illu/ration3 ,figure #bb4--;,,broadside ,,publi%$ ,,aft] ,,comm5cem5t ,,( ,,"w on ! ,?ames ,tunnel1 #ahbg4 7,,mht collections47 ,,op5 ,,to ,,! ,,public ,,e ,,day 7,sundays except$7 f ,sev5 9 ! ,morn+1 until ,eight 9 ! ,ev5+1 ,,! ,,?ames ,,tunnel4 ,fig4 #a %[s a transv]se section ( ! ,?ames1 & b5ea? x a longitud9al section ( ! ,tunnel1 z x w be :5 complet$2 ) ! asc5ts 9 ! incl9ations 9 :i* !y w be f9i%$4 ,fig4 #b %[s ! two ar*$ entrances ( ! ,tunnel f ! %aft4 ,fig4 #c is a repres5tation ( ! iron %ield1 & %[s a workman 9 ea* ( ! comp>tm5ts4 ,! ,entrance to ! ,tunnel is ne> to ,ro!rhi! ,*ur*1 & ne>ly opposite to ! ,london-,docks4 ,! ne>e/ l&+ place f ! riv] is ,*ur* ,/airs4 ,! ,gre5wi* & ,dept=d coa*es :i* g ! l[] road1 />t h\rly f ,*>+-cross1 & ,grace*ur*-/reet1 & pass close by ! works at ,ro!rhi!4 ,books relative to ! ,tunnel may be _h at ! works4 ,! ,public may view ! ,tunnel e day 7,sundays except$7 f ,sev5 9 ! morn+ until ,eight 9 ! ,ev5+1 ^u paym5t ( ,"o ,%ill+ ea* ,p]son4 ,! extreme nor!rn end ( ! ,tunnel is = ! pres5t secur$ by a /rong wall2 b visitors w f9d a dry1 w>m1 & gravell$ prom5ade1 z f> z to almo/ ! c5tre ( ! riv]1 & brilliantly light$ ) oil gas4 ,! entrance is f ,ro!rhi! ,/reet1 & by a safe1 commodi\s1 & easy /air case4 ,h4 ,teape ,son1 ,pr9t]s1 ,t[]-hill1 ,london4 ,illu/ration3 ,figure #bc4--,,v]tical ,,section ,,?r\gh ,,brunel',s ,,%ield4 ,! long lev]1 x1 support$ ! wood c5t]+ = turn+ ! masonry ar*es ( ! l9+4 7,,law1 ,a ,memoir ( ! ,?ames ,tunnel47 ,illu/ration3 ,figure #bd4--,,?ames ,,tunnel4 ,,section ,,?r\gh riv]b$ & tunnel foll[+ "o ( ! break-?r\ghs ( ! riv]4 ,inspection ( ! damage ) a div+ bell4 7,,beami%1 ,a ,memoir ( ! ,life ( ,sir ,m>c ,isamb>d ,brunel47 ,! ,t[] ,subway at fir/ op]at$ ) cyl9drical c>s t ne>ly fill$ ! #g-;foot bore2 ! c>s 7 drawn by cables p[]$ by small /eam eng9es 9 ! %afts4 ,?is mode ( p[] _h previ\sly be5 us$ 9 pass5g] s]vice only on ! ,gre5wi* ,/reet elevat$ railway 9 ,new ,york4 ,lat] ! c>s 7 ab&on$ z unpr(itable & ! tunnel turn$ into a footway 7fig4 #cb74 ,?is small tunnel1 ! successful driv+ due entirely to ,grea!ad's skill1 0 ! =]unn] ( ! mod]n subaque\s tunnel4 ,9 x1 two ( ! ?ree elem5ts ess5tial to su* "w !reaft] 7 fir/ appli$3 ! "o-piece movable %ield ( circul> section1 & ! segm5tal ca/-iron l9+4 ,! docum5tation ( ?is "w is f> ?9n] ?an = ! ,?ames ,tunnel4 ,! mo/ accurate s\rce ( te*nical in=mation is a brief hi/orical acc\nt 9 ,copp]?waite's classic ,tunnel ,%ields & ! ,use ( ,compress$ ,air 9 ,subaque\s ,works1 publi%$ 9 #aijf4 ,copp]?waite1 a successful tunnel eng9e]1 lam5ts ! fact t he 0 able to turn up no draw+ or orig9al data on ?is fir/ %ield ( ,grea!ad's1 b he pres5ts a sket* ( x prep>$ 9 ! ,grea!ad (fice 9 #ahie1 :i* is presumably a fair repres5tation 7fig4 #cc74 ,! ,t[] ,subway model 0 built on ! basis ( ?is & sev]al woodcuts ( ! work+ area t appe>$ contemporane\sly 9 ! illu/rat$ press4 ,9 ?is & ! adjac5t model ( ,bea*'s ,broadway ,subway1 ! tunnel axis has be5 plac$ on an angle to ! view]1 project+ ! bore into ! case s t ! complete circle ( ! work+ face is includ$ = a m sugge/ive effect4 ,?is 0 possible because ( ! %ort l5g? ( ! "w includ$4 ,h5ry ,s4 ,dr9k]1 also a tunnel eng9e] & au?or ( ! mo/ compreh5sive "w on tunnel+ ev] publi%$1 treats rock tunnel+ 9 exhau/ive detail up to #ahgh4 ,8 notice ( :at he t]ms subm>9e tunnel+ is extremely brief4 ,he does1 h[ev]1 draw a mo/ int]e/+ comp>ison betwe5 ! fir/ ,?ames ,tunnel1 built by ,brunel1 & ! second1 built by ,grea!ad #bf ye>s lat]3 ,,fir/ ,,?ames ,,tunnel ,,second ,,?ames ,,tunnel 7,,t[] ,,subway7 ,brickwork l9+1 #ch feet ,ca/-iron l9+ ( #h feet wide by #bb-a_/b feet high4 outside diamet]4 #abj-ton ca/-iron %ield1 #b-a_/b-ton1 wr\ght-iron %ield1 accommodat+ #cf m9]s4 accommodat+ at mo/ #c m54 ,work+s fill$ by irruption ,wat] enc\nt]$ at almo/ ( riv] five times4 any "t c\ld h be5 ga!r$ 9 a /able pail4 ,eighte5 ye>s elaps$ betwe5 ,"w complet$ 9 ab\t />t & f9i% ( "w4 elev5 mon?s4 ,co/3 #c1jjj1jjj4 ,co/3 #ajj1jjj4 ,illu/ration3 ,figure #be4--,,transv]se ,,section ,,?r\gh ,,%ield1 aft] inundation4 ,su* disa/]s1 z well z ! inconsi/5cy ( ! riv]b$'s composition1 s]i\sly di/urb$ ! alignm5t ( ! %ield's individual sections4 7,,law1 ,a ,memoir ( ! ,?ames ,tunnel47 ,illu/ration3 ,figure #bf4--,,longitud9al ,,section ,,?r\gh ,,?ames ,,tunnel aft] s&bagg+ to close a break 9 ! riv]b$4 ,! tunnel is fill$ ) silt & wat]4 7,,law1 ,a ,memoir ( ! ,?ames ,tunnel47 ,illu/ration3 ,figure #bg4--;,,int]ior ,,( ,,! ,,?ames ,,tunnel %ortly aft] completion 9 #ahdc4 7,photo c\rtesy ( ,new ,york ,public ,libr>y ,picture ,collection47 ,illu/ration3 ,figure #bh4--,,?ames ,,tunnel 9 use by ,london ,und]gr\nd railway4 7,illu/rat$ ,london ,news1 #ahfi87 ,illu/ration3 ,figure #bi4--,,plac+ ,a segm5t ( ca/-iron l9+ 9 ,grea!ad's ,t[] ,subway1 #ahfi4 ,to ! re> is ! %ield's diaphragm or bulkhead4 ,,mht model--#a-a_/b scale4 7,smi?sonian photo #dibfj-;,b47 ,,bea*',s ,,broadway ,,subway ,almo/ simultane\sly ) ! con/ruction ( ! ,t[] ,subway1 ! fir/ ,am]ican %ield tunnel 0 driv5 by ,alfr$ ,ely ,bea* 7#ahbf-ahif74 ,bea*1 z editor ( ! ,sci5tific ,am]ican & inv5tor (1 among o!r ?+s1 a successful typewrit] z e>ly z #ahef1 0 well kn[n & respect$ 9 te*nical circles4 ,he 0 n a civil eng9e]1 b _h become conc]n$ ) ,new ,york's press+ traffic problem 7ev5 !n7 & z a solution1 develop$ plans = a rapid-transit subway to ext5d ! l5g? ( ,broadway4 ,he inv5t$ a %ield z an adjunct to ?is sy/em1 solely to p]mit driv+ ( ! tunnel )\t di/urb+ ! ov]ly+ /reets4 ,an active pat5t attorney z well1 ,bea* mu/ c]ta9ly h kn[n ( & /udi$ ! exi/+ pat5ts = tunnel+ %ields1 :i* 71 )\t exception1 ,briti%4 ,9 c]ta9 aspects 8 %ield resembl$ ! "o pat5t$ by ,b>l[ 9 #ahfd1 b nev] built4 ,h[ev]1 "w on ! ,bea* tunnel />t$ 9 #ahfi1 s close 9 "t to t on ! ,t[] ,subway1 t x is unlikely t !re 0 any influ5ce f t s\rce4 ,bea* _h himself pat5t$ a %ield1 9 ,june #ahfi1 a two-piece1 sectional design t bore no resemblance to ! "o us$4 ,8 subway plan _h be5 fir/ introduc$ at ! #ahfg fair ( ! ,am]ican ,in/itute 9 ! =m ( a %ort plywood tube ?r\gh :i* a small1 close-fitt+ c> 0 bl[n by a fan4 ,! c> c>ri$ #ab pass5g]s4 ,s5s+ opposition to ! subway s*eme f ,tammany1 9 #ahfh ,bea* obta9$ a *>t] to place a small tube b5ea? ,broadway = transport+ mail & small packages pneumatically1 a plan he advocat$ indep5d5tly ( ! pass5g] subway4 ,illu/ration3 ,figure #cj4--;,,contempor>y ,,illu/rations ( ,t[] ,subway works us$ z basis ( ! model 9 ! ,museum ( ,hi/ory & ,te*nology4 7,illu/rat$ ,london ,news1 #ahfi47 ,,advanc+ ,,! ,,%ield4 ,,fitt+ ,,! ,,ca/+s4 ,illu/ration3 ,figure #ca4--;,,excavation ,,9 ,,front ,,( ,,%ield1 ,t[] ,subway4 ,?is 0 possible because ( ! /iffness ( ! clay enc\nt]$4 ,,mht model--front ( model %[n 9 fig4 #bi4 7,smi?sonian photo #dibfj-;,a47 ,"u ?is ?9 pret5se ( legal au?orization1 ! sub-rosa excavation began f ! basem5t ( a clo?+ /ore on ,w>r5 ,/reet ne> ,broadway4 ,! #h-;foot-diamet] tunnel ran ea/w>d a %ort di/ance1 made a #ij-;degree turn1 & !nce s\?w>d "u ,broadway to /op a block away "u ! s\? side ( ,murray ,/reet4 ,! total di/ance 0 ab\t #cab feet4 ,"w 0 c>ri$ on at night 9 total secrecy1 ! actual tunnel+ tak+ #eh nights4 ,at ! ,w>r5 ,/reet t]m9al1 a wait+ room 0 excavat$ & a l>ge ,roots bl[] in/all$ = propulsion ( ! s+le pass5g] c>4 ,! plan 0 simil> to t us$ ) ! model 9 #ahfg3 ! cyl9drical c> fitt$ ! circul> tunnel ) only slight circumf]5tial cle>ance4 ,! bl[] creat$ a pl5um )9 ! wait+ room & tunnel area beh9d ! c> ( ab\t #j4be p\nds p] squ>e in*1 result+ 9 a ?ru/ on ! c> ( almo/ a ton1 n acc\nt+ = bl[by4 ,! c> 0 ?us bl[n along its c\rse1 & 0 return$ by rev]s+ ! bl[]'s suction & dis*>ge ducts to produce an equival5t vacuum )9 ! tunnel4 ,illu/ration3 ,figure #cb4--;,,int]ior ,,( ,,complet$ ,,t[] ,,subway4 7,,?ornbury1 ,old & ,new ,london1 #ahhg1 vol4 #a1 p4 #abf47 ,! sy/em op5$ 9 ,febru>y ( #ahgj & rema9$ 9 op]ation = ab\t a ye>4 ,bea* 0 ultimately subdu$ by ! ho/ile influ5ces ( ,boss ,twe$1 & ! project 0 completely ab&on$4 ,)9 a v few m ye>s ! fir/ comm]cially op]at$ elevat$ l9e 0 built1 b ! subway did n a*ieve legitimate /atus 9 ,new ,york until ! op5+ ( ! ,int]bor\gh l9e 9 #aijd4 ,ironically1 its r\te trav]s$ ,broadway = almo/ ! l5g? ( ! isl&4 ,illu/ration3 ,figure #cc4--,,v]tical ,,section ?r\gh ! ,grea!ad %ield us$ at ! ,t[] ,subway1 #ahfi4 ,! fir/ "o-piece %ield ( circul> section4 7,,copp]?waite1 ,tunnel ,%ields & ! ,use ( ,compress$ ,air 9 ,subaque\s ,works47 ,! ,bea* %ield op]at$ ) p]fect success 9 ?is brief trial1 al?\gh ! loose s&y soil enc\nt]$ 0 admitt$ly n a sev]e te/ ( its qualities4 ,no diaphragm 0 us$2 in/ead a s]ies ( #h horizontal %elves ) %>p5$ lead+ edges ext5d$ across ! front op5+ ( ! %ield4 ,! out/&+ feature ( ! ma*9e 0 ! sub/itution = ! propell+ screws us$ by ,brunel & ,grea!ad ( #ah hydraulic rams1 set ar\nd its circumf]5ce4 ,^! 7 f$ by a s+le h&-op]at$ pump1 se5 9 ! c5t] ( figure #cd4 ,by ?is means ! c\rse ( ! %ield's =w>d movem5t c\ld be controll$ ) a conv5i5ce & precision n atta9able ) screws4 ,v]tical & horizontal deflection 0 a*iev$ by ?rottl+ ! supply ( wat] to c]ta9 ( ! rams1 :i* c\ld be individually controll$1 caus+ great] pressure on "o portion ( ! %ield ?an ano!r4 ,?is sy/em has n *ang$ 9 ! ensu+ "t1 except1 ( c\rse1 9 ! sub/itution ( me*anically produc$ hydraulic pressure = h&4 ,illu/ration3 ,figure #cd4--;,,bea*',s ,broadway ,subway4 ,advanc+ ! %ield by hydraulic rams1 #ahfi4 ,,mht model--#a-a_/b scale4 7,smi?sonian photo #dibfj-;,e47 ,illu/ration3 ,figure #ce4--,,v]tical ,,section ?r\gh ! ,bea* %ield us$ on ! ,broadway ,subway1 %[+ ! horizontal %elves 7,c71 iron cutt+ r+ 7,b71 hydraulic rams 7,d71 hydraulic pump 7,f71 & re> protective skirt 7,h74 7,sci5tific ,am]ican1 ,m>* #e1 #ahgj47 ,unlike ! driv+ ( ! ,t[] ,subway1 no excavation 0 done 9 front ( ! %ield4 ,r1 ! %ield 0 =c$ by ! rams into ! soil = ! l5g? ( _! /roke1 ! mat]ial :i* ent]$ be+ support$ by ! %elves4 ,?is 0 remov$ f ! %elves & haul$ (f4 ,! ram plung]s !n 7 )drawn & a #af-;in* l5g? ( ! p]man5t l9+ built up )9 ! %elt] ( ! %ield's tail r+4 ,aga9/ ?is1 ! rams bore = ! next advance4 ,masonry l9+ 0 us$ 9 ! /raight section2 ca/-iron 9 ! curv$4 ,! juncture is %[n 9 ! model4 ,illu/ration3 ,figure #cf4--;,,int]ior ( ,bea* ,subway %[+ iron l9+ on curv$ section & ! pneumatically p[]$ pass5g] c>4 ,view f wait+ room4 7,sci5tific ,am]ican1 ,m>* #e1 #ahgj47 ,enl>g$ v]sions ( ! ,bea* %ield 7 us$ 9 a few tunnels 9 ! ,midwe/ 9 ! e>ly #ahgj's1 b f !n until #ahhf ! %ield me?od1 = no cle> reason1 aga9 ent]$ a p]iod ( disuse f9d+ no application on ei!r side ( ! ,atlantic despite its virtually unqualifi$ pro( at ! h&s ( ,grea!ad & ,bea*4 ,little precise in=mation rema9s on ?is "w4 ,! ,bea* sy/em ( pneumatic transit is describ$ fully 9 a well-illu/rat$ booklet publi%$ by him 9 ,janu>y #ahfh1 9 :i* ! ,am]ican ,in/itute model is %[n1 & _m project$ sy/ems ( pneumatic propulsion z well z ( subt]ranean & subaque\s tunnel+ describ$4 ,bea* aga9 7presumably7 is au?or ( ! sole contempor>y acc\nt ( ! ,broadway ,subway1 :i* appe>$ 9 ,sci5tific ,am]ican foll[+ its op5+ e>ly 9 #ahgj4 ,includ$ are good views ( ! tunnel & c>1 ( ! %ield 9 op]ation1 &1 mo/ important1 a v]tical sectional view ?r\gh ! %ield 7fig4 #ce74 ,x is int]e/+ to note t optical surveys = ma9t5ance ( ! c\rse app>5tly 7 n us$4 ,! article illu/rat$ & describ$ ! driv+ ea* night ( a jo9t$ iron rod up ?r\gh ! tunnel ro( to ! /reet1 tw5ty or s feet above1 = te/+ ! position4 ,,! ,,fir/ ,,hudson ,,riv] ,,tunnel ,despite ! ultimate success ( ,brunel's ,?ames ,tunnel 9 #ahdc1 ! %ield 9 t case af=d$ only mod]ately reliable protection because ( ! fluidity ( ! soil driv5 ?r\gh1 & its t5d5cy to ent] ! works ?r\gh ! smalle/ op5+ 9 ! %ield's def5se4 ,an ,engli% doctor :o _h made physiological /udies ( ! effects on workm5 ( ! high air pressure )9 div+ bells is said to h recomm5d$ to ,brunel 9 #ahbh t he introduce an atmosph]e ( compress$ air into ! tunnel to exclude ! wat] & support ! "w face4 ,?is plan 0 fir/ =mally describ$ by ,sir ,?omas ,co*rane 7#agge-ahfj7 9 a ,briti% pat5t ( #ahcj4 ,consci\s ( ,brunel's problems1 he propos$ a sy/em ( %aft s9k+1 m9+1 & tunnel+ 9 wat]-be>+ mat]ials by fill+ ! excavat$ area ) air suffici5tly above atmosph]ic pressure to prev5t ! wat] f ent]+ & to support ! e>?4 ,9 ?is1 & 8 description ( air locks = passage ( m5 & mat]ials betwe5 ! atmosph]e & ! pressuriz$ area1 ,co*rane fully outl9$ ! ess5tial features ( pneumatic excavation z develop$ s9ce4 ,illu/ration3 ,figure #cg4--,,! ,,giant ,,roots ,,lobe-,,type ,,bl[] us$ = propell+ ! c>4 ,9 #ahci1 a ,fr5* eng9e] fir/ us$ ! sy/em 9 s9k+ a m9e %aft ?r\gh a wat]y /ratum4 ,f !n on1 ! s9k+ ( %afts1 & some:at lat] ! con/ruction ( bridge pi] f\ndations1 by ! pneumatic me?od became almo/ commonplace eng9e]+ practice 9 ,europe & ,am]ica4 ,n until #ahgi h[ev]1 0 ! sy/em tri$ 9 tunnel+ "w1 & !n1 z ) ! %ield t5 ye>s e>li]1 almo/ simultane\sly "h & abroad4 ,! fir/ application 0 9 a small riv] tunnel 9 ,antw]p1 only #e feet 9 height4 ,?is project 0 successfully complet$ rely+ on compress$ air alone to support ! e>?1 no %ield be+ us$4 ,! importance ( ! "w _c be consid]$ great due to its lack ( scope4 ,illu/ration3 ,figure #ch4--,,te/+ ,,alignm5t ( ! ,broadway ,subway at night by driv+ a jo9t$ rod up to /reet level4 7,sci5tific ,am]ican1 ,m>* #e1 #ahgj47 ,9 #ahga ,dewitt ,c4 ,hask9 7#ahbb-aijj71 a we/ coa/ m9e & railroad build]1 became int]e/$ 9 ! pneumatic caissons !n be+ us$ to f\nd ! riv] pi]s ( ,eads' ,mississippi ,riv] bridge at ,/4 ,l\is4 ,9 app>5t total ignorance ( ! ,co*rane pat5t1 he evolv$ a simil> sy/em = tunnel+ wat]-be>+ m$ia1 & 9 #ahgc propos$ con/ruction ( a tunnel ?r\gh ! silt b5ea? ! ,hudson to provide rail connection betwe5 ,new ,j]sey & ,new ,york ,city4 ,illu/ration3 ,figure #ci4--;,,hask9',s pneumatically driv5 tunnel "u ! ,hudson ,riv]1 #ahhj4 ,9 ! eng9e room at top left 0 ! ma*9]y = hoi/+1 g5]at+ electricity = light+1 & air compress+4 ,! air lock is se5 9 ! wall ( ! brick %aft4 ,,mht model--#j4c scale4 7,smi?sonian photo #dibfj47 ,illu/ration3 ,figure #dj4--;,,arti/',s ,,conception ,,( ,,m9]s escap+ into ! air lock dur+ ! bl[\t 9 ,hask9's tunnel4 ,x w\ld be difficult to imag9e a site m 9 ne$ ( su* communication4 ,all l9es f ! s\? t]m9at$ along ! we/ %ore ( ! riv] & ! imm5se traffic--c>s1 freight & pass5g]s--0 c>ri$ across to ,manhattan ,isl& by f]ry & b>ge ) /agg]+ inconv5i5ce & at enorm\s co/4 ,a bridge w\ld h be51 & /ill is1 almo/ out ( ! "q due n only to ! wid? ( ! cross+1 b to ! flatness ( bo? banks4 ,to provide suffici5t navigational cle>ance 7)\t a drawspan71 impracticably long approa*es w\ld h be5 necess>y to obta9 a p]missibly g5tle grade4 ,hask9 =m$ a tunnel+ company & began "w ) ! s9k+ ( a %aft 9 ,hobok5 on ! ,new ,j]sey side4 ,9 a mon? x 0 halt$ because ( an injunction by1 curi\sly1 ! ,d ,l ,w ,railroad1 :o fe>$ = _! va/ inve/m5t 9 t]m9al & m>9e facilities4 ,n until ,novemb] ( #ahgi 0 ! injunction lift$ & "w aga9 comm5c$4 ,! %aft 0 complet$ & an air lock locat$ 9 "o wall f :i* ! tunnel prop] 0 to be c>ri$ =w>d4 ,x 0 ,hask9's plan to use no %ield1 rely+ solely on ! pressure ( compress$ air to ma9ta9 ! "w faces & prev5t ! entry ( wat]4 ,! air 0 admitt$ 9 late ,decemb]1 & ! fir/ l>ge-scale pneumatic tunnel+ op]ation laun*$4 ,a s+le #bf-;foot1 d\ble-track bore 0 at fir/ und]tak51 b a "w face ( su* diamet] prov$ unmanageable & two oval tubes #ah feet high by #af feet wide 7 sub/itut$1 ea* to c>ry a s+le track4 ,"w w5t =w>d ) reasonable facility1 consid]+ ! lack ( prec$5t4 ,a tempor>y entrance 0 =m$ ( %eet-iron r+s f ! air lock d[n to ! tunnel grade1 at :i* po9t ! p]man5t "w ( ! nor? tube 0 />t$4 ,imm$iately beh9d ! excavation at ! face1 a l9+ ( ?9 wr\ght-iron plates 0 built up1 to provide =m = ! #b-;foot1 p]man5t brick l9+ t foll[$4 ,! ?ree /ages are %[n 9 ! model 9 ab\t _! prop] relation%ip ( progress4 ,! "w is %[n pass+ b5ea? an old timb]-crib bulkhead1 us$ = /abiliz+ ! %orel9e4 ,! silt ( ! riv]b$ 0 ab\t ! consi/5cy ( putty & "u good conditions =m$ a secure b>ri] betwe5 ! excavation & ! riv] above4 ,x 0 easily excavat$1 & = removal 0 mix$ ) wat] & bl[n out ?r\gh a pipe into ! %aft by ! high] pressure 9 ! tunnel4 ,ab\t half 0 left 9 ! bore = removal lat]4 ,! basic s*eme 0 workable1 b 9 op]ation an extreme precision 0 requir$ 9 regulat+ ! air pressure 9 ! "w area4#e ,x 0 soon f\nd t !re exi/$ an #aa-psi diff]5ce betwe5 ! pressure ( wat] on ! top & ! bottom ( ! work+ face1 due to ! #bb-;foot height ( ! unl9$ op5+4 ,?us1 x 0 impossible to ma9ta9 p]fect pneumatic balance ( ! ext]nal pressure ov] ! entire face4 ,x 0 necess>y to /rike an av]age ) ! result t "s wat] ent]$ at ! bottom ( ! face :]e ! wat] pressure 0 greate/1 & "s air leak$ out at ! top :]e ! wat] pressure 0 bel[ ! air pressure4 ,con/ant att5tion 0 ess5tial3 sev]al m5 did no?+ b wat* ! behavior ( ! leaks & adju/$ ! pressure z ! gr\nd d5sity *ang$ ) advance4 ,air 0 suppli$ by sev]al /eam-driv5 compressors at ! surface4 ,! air lock p]mitt$ passage back & =? ( m5 & supplies betwe5 ! atmosph]e & ! "w area1 )\t di/urb+ ! pressure diff]5tial4 ,?is pr9ciple is demon/rat$ by an animat$ model set into ! ma9 model1 to ! left ( ! %aft 7fig4 #ci74 ,! v>iation ( pressure )9 ! lock *amb] to mat* ! atmosph]e or ! pressuriz$ area1 dep5d+ on ! direction ( passage1 is cle>ly %[n by simplifi$ valves & gauges1 & by ! use ( light 9 v>y+ color d5sity4 ,9 ! ,hask9 tunnel1 #e to #aj m9utes 7 tak5 to pass ! m9]s ?r\gh ! lock s z to avoid too abrupt a physiological *ange4 ,despite caution1 a bl[\t occurr$ 9 ,july #ahhj due to air leakage n at ! face1 b ar\nd ! tempor>y entrance4 ,"o door ( ! air lock jamm$ & tw5ty m5 dr[n$1 result+ 9 an inquiry :i* br\ght =? mu* ( ! di/ru/ ) :i* ,hask9 0 reg>d$ by ! eng9e]+ pr(ession4 ,8 ability & qualifications 7 subject$ to ! bitt]e/ attack 9 & by ! te*nical press4 ,!re is "s indication t1 al?\gh ! project began ) a /aff ( compet5t eng9e]s1 !y 7 ali5at$ by ,hask9 9 ! c\rse ( "w & at lea/ "o )drew4 ,hask9's rem>ks 9 8 own def5se indicate t "s ( ! d5unciation 0 und\bt$ly ju/ifi$4 ,& yet1 despite ?is reaction1 ! fundam5tal m]it ( ! pneumatic tunnel+ me?od _h be5 demon/rat$ by ,hask9 & 0 imm$iately recogniz$ & freely ackn[l$g$4 ,x 0 app>5t at ! same "t1 h[ev]1 t air by itself did n provide a suffici5tly reliable support = l>ge-area tunnel works 9 un/able gr\nd1 & ?is rema9s ! only major subaque\s tunnel "w driv5 ) air alone4 ,illu/ration3 ,figure #da4--,,location ,,( ,,hudson ,,riv] ,,tunnel4 7,leslie's ,weekly1 #ahgi47 ,aft] ! accid5t1 "w cont9u$ "u ,hask9 until #ahhb :5 funds ran out4 ,ab\t #afjj feet ( ! nor? tube & #fjj feet ( ! s\? tube _h be5 complet$4 ,grea!ad resum$ op]ations ) a %ield = a ,briti% company 9 #ahhi1 b exhau/ion ( funds aga9 caus$ /oppage 9 #ahia4 ,! tunnel 0 f9ally complet$ 9 #aijd1 & is n[ 9 use z "p ( ! ,hudson & ,manhattan rapid-transit sy/em1 nev] provid+ ! s\ght-aft] rail l9k4 ,a spl5did docum5t ( ! ,hask9 portion ( ! "w is ,s4 ,d4 ,v4 ,burr's ,tunnel+ ,"u ! ,hudson ,riv] publi%$ 9 #ahhe4 ,x is bas$ entirely ^u fir/h& mat]ial & conta9s draw+s ( mo/ ( ! "w1 includ+ ! auxili>y app>atus4 ,x is int]e/+ to note t electric illum9ation 7arc1 n inc&esc5t1 lights7 & telephones 7 us$1 unque/ionably ! fir/ employm5t ( ei!r 9 tunnel "w4 ,illu/ration3 ,figure #db4--,,/4 ,,clair ,,tunnel4 ,view ( front ( %ield %[+ me?od ( excavation 9 firm /rata4 ,inc&esc5t electric illum9ation 0 us$4 #ahhi-ij4 ,,mht model--#a scale4 7,smi?sonian photo #dibfj-;,d47 ,,! ,,/4 ,,clair ,,tunnel ,! f9al model ( ! s(t-gr\nd s]ies reflects1 z did ! ,hoosac ,tunnel model = h>d-rock tunnel+1 f9al em]g5ce into ! mod]n p]iod4 ,al?\gh ! ,/4 ,clair ,tunnel 0 complet$ ov] #gj ye>s ago1 x typifies 9 its me?od ( con/ruction1 ! basic proc$ures ( subaque\s "w 9 ! pres5t day4 ,! ,?ames ,tunnel ( ,brunel1 & ,hask9's ef=ts b5ea? ! ,hudson1 _h cle>ly %[n t by !mselves1 bo? ! %ield & pneumatic sy/ems ( driv+ ?r\gh fluid gr\nd 7 defective 9 practice = tunnels ( l>ge area4 ,note t ! e>lie/ successful works by ea* me?od _h be5 ( v small area1 s t ! influ5ce ( adv]se conditions 0 greatly dim9i%$4 ,! fir/ man to p]ceive & seize ^u ! b5efits to be ga9$ by comb9+ ! two sy/ems 01 mo/ fitt+ly1 ,grea!ad4 ,al?\gh he _h project$ ! te*nique e>li]1 9 driv+ ! und]gr\nd ,city & ,s\? ,london ,railway 9 #ahhf1 he br\ght toge!r = ! fir/ "t ! ?ree fundam5tal elem5ts ess5tial = ! practical tunnel+ ( s(t1 wat]-be>+ gr\nd3 compress$-air support ( ! "w dur+ con/ruction1 ! movable %ield1 & ca/-iron1 p]man5t l9+4 ,! m>riage 0 a happy "o inde$2 ! limitations ( ea* sy/em 7 almo/ p]fectly ov]come by ! qualities ( ! o!rs4 ,! conditions prevail+ 9 #ahhb at ! ,s>nia1 ,ont>io1 t]m9al ( ! ,gr& ,trunk ,railway1 bo? op]ational & physical1 7 almo/ precisely ! same z ^? :i* inspir$ ! und]tak+ ( ! ,hudson ,riv] ,tunnel4 ,! heavy traffic at ?is vital ,u4,s4--,canada rail int]*ange 0 f]ri$ inconv5i5tly across ! wide ,/4 ,clair ,riv]1 & ! bank & riv] conditions preclud$ con/ruction ( a bridge4 ,a tunnel 0 project$ by ! railway 9 t ye>1 ! "t :5 ,hask9's tribulations 7 at _! height4 ,p]haps because ( ?is lack ( prec$5t = a "w ( su* size1 no?+ 0 done imm$iately4 ,9 #ahhd ! railway organiz$ a tunnel company2 9 #ahhf te/ bor+s 7 made 9 ! riv]b$ & small exploratory drifts 7 />t$ across f bo? banks by normal me?ods ( m9e timb]+4 ,! natural gas1 quicks&1 & wat] enc\nt]$ soon /opp$ ! "w4 ,illu/ration3 ,figure #dc4--,,re> ,,view ,,( ,,/4 ,,clair ,,%ield %[+ ! erector arm plac+ a ca/-iron l9+ segm5t4 ,! ?ree motions ( ! arm--axial1 radial1 & rotational1 7 manually p[]$4 7,smi?sonian photo #dibfj-;,c47 ,x 0 at ?is "t t ! railway's presid5t visit$ ,grea!ad's ,city & ,s\? ,london work+s4 ,! obvi\s answ] to ! ,/4 ,clair problem lay 9 ! successful conduct ( ?is subway4 ,joseph ,hobson1 *ief eng9e] ( ! ,gr& ,trunk & ( ! tunnel project1 9 design+ a %ield1 is said to h se>*$ = draw+s ( ! %ields us$ 9 ! ,broadway & ,t[] ,subways ( #ahfh-i1 b unable to locate any1 he reli$ to a limit$ ext5t on ! small draw+s ( ^? 9 ,dr9k]'s volume4 ,!re is no explanation z to :y he did n h draw+s ( ! ,city & ,s\? ,london %ield at t mom5t 9 use1 unless "o consid]s ! r unlikely possibility t ,grea!ad ma9ta9$ its design 9 secrecy4 ,illu/ration3 ,figure #dd4--,,op5+ ,,( ,,! ,,/4 ,,clair ,,tunnel1 #ahia4 7,photo c\rtesy ( ,detroit ,libr>y1 ,burton ,hi/orical ,collection47 ,! ,hobson %ield foll[$ ,grea!ad's z closely z any o!r1 9 hav+ a diaphragm ) closable doors1 b a modification ( ,bea*'s %>p5$ horizontal %elves 0 also us$4 ,h[ev]1 ^! function$ m z work+ plat=ms ?an supports = ! e>?4 ,! ma*9e 0 #ba-a_/b feet 9 diamet]1 an unprec$5t$ size & almo/ twice t ( ,grea!ad's curr5t "o4 ,x 0 driv5 by #bd hydraulic rams4 ,?r\gh\t ! entire prelim9>y consid]ation ( ! project !re 0 a m>k$ s5se ( caution t am\nt$ to :at seems an almo/ total lack ( confid5ce 9 success4 ,comm5cem5t ( ! "w f v]tical %afts 0 plann$ s t if ! tunnel itself fail$1 no exp5diture w\ld h be5 made = approa* "w4 ,9 ,april #ahhh1 ! %afts 7 />t$ ne> bo? riv]banks1 b be=e rea*+ prop] dep? ! almo/ fluid clay & silt fl[$ up fa/] ?an x c\ld be excavat$ & ?is plan 0 ab&on$4 ,aft] ?is second inauspici\s />t1 long op5 approa* cuts 7 made & ! "w f9ally began4 ,! portals 7 e/abli%$ 9 ! cuts1 sev]al ?\s& feet back f ea* bank & !re ! tunnel+ itself began4 ,! portions "u ! %ore 7 driv5 )\t air4 ,:5 ! banks 7 rea*$1 brick bulkheads conta9+ air locks 7 built across ! op5+ & ! section b5ea? ! riv]1 ab\t #c1gaj feet long1 driv5 "u air pressure ( #aj to #bh p\nds above atmosph]e4 ,= mo/ ( ! way1 ! clay 0 firm & !re 0 little air leakage4 ,x 0 f\nd t horses c\ld n survive 9 ! compress$ air1 & s mules 7 us$ "u ! riv]4 ,9 ! firm clay1 excavation 0 c>ri$ on sev]al feet 9 front ( ! %ield1 z %[n 9 ! model 7fig4 #db74 ,ab\t twelve m9]s work$ at ! face4 ,h[ev]1 9 c]ta9 /rata ! clay enc\nt]$ 0 s fluid t ! %ield c\ld be simply driv5 =w>d by ! rams1 caus+ ! muck to fl[ 9 at ! door op5+s )\t excavation4 ,aft] ea* advance1 ! rams 7 retract$ & a r+ ( iron l9+ segm5ts built up1 z 9 ! ,t[] ,subway4 ,"h1 = ! fir/ "t1 an erector arm 0 us$ = plac+ ! segm5ts1 :i* weigh$ ab\t half a ton4 ,9 all respects1 ! "w advanc$ ) wond]ful facility & lack ( op]ational difficulty4 ,consid]+ ! l>ge area1 no subaque\s tunnel _h ev] be5 driv5 ) su* spe$4 ,! av]age mon?ly progress = ! ,am]ican & ,canadian head+s total$ #dee feet1 & at top effici5cy #aj r+s or a l5g? ( #ae4c feet c\ld be set 9 a #bd-;h\r day 9 ea* head+4 ,! #f1jjj feet ( tunnel 0 driv5 9 j a ye>2 ! two %ields met vis-a-vis 9 ,augu/ ( #ahij4 ,! transition 0 complete4 ,! "w _h be5 closely foll[$ by ! te*nical j\rnals & ! reports ( its successful accompli%m5t ?us 7 br\ght to ! att5tion ( ! entire civil eng9e]+ pr(ession4 ,z ! fir/ major subaque\s tunnel complet$ 9 ,am]ica & ! fir/ 9 ! _w ( a size able to accommodate full-scale rail traffic1 ! ,/4 ,clair ,tunnel s]v$ to dispel ! d\bts surr\nd+ su* "w1 & e/abli%$ ! patt]n = a mode ( tunnel+ :i* has s9ce *ang$ only 9 matt]s ( detail4 ,( ! eight models1 only ?is "o 0 built "u ! positive guidance ( orig9al docum5ts4 ,9 ! possession ( ! ,canadian ,national ,railways are draw+s n only ( all elem5ts ( ! %ield & l9+1 b ( mu* ( ! auxili>y app>atus us$ 9 con/ruction4 ,su* mat]ials r>ely survive1 & d s 9 ?is case only because ( ! =esight ( ! railway :i*1 to avoid pay+ a high pr(it m>g9 to a private contractor z comp5sation = ! risk & unc]ta9ty involv$1 c>ri$ ! contract itself &1 !re=e1 pres]v$ all orig9al draw+ records4 ,:ile ! eng9e]+ ( tunnels has be5 compreh5sively treat$ 9 ?is pap] f ! hi/orical /&po9t1 x is well to /ill reflect t ! advances made 9 tunnel+ h n p]ceptibly remov$ ! elem5ts ( unc]ta9ty b h only provid$ m positive & effective means ( c\nt]+ _! =ces4 ,/ill to be fac$ are ! surprises ( hidd5 /reams1 geologic faults1 %ifts ( /rata1 un/able mat]ials1 & areas ( extreme pressure & temp]ature4 ,,bibliography ,,agricola1 ,,georgius4 ,de re ,metallica4 ,engli% transl4 ,h4 ,c4 & ,l4 ,h4 ,hoov] 7,! ,m9+ ,magaz9e1 ,london1 #aiab74 ,basel3 ,frob51 #aeef4 ,,bea*1 ,,alfr$ ,,ely4 ,! pneumatic dispat*4 ,new ,york3 ,! ,am]ican ,news ,company1 #ahfh4 ,,beami%1 ,,ri*>d4 ,a memoir ( ! life ( ,sir ,m>c ,isamb>d ,brunel4 ,london3 ,longmans1 ,gre51 ,longmans & ,rob]ts1 #ahfb4 ,,burr1 ,s4 ,d4 ,v4 ,tunnel+ "u ! ,hudson ,riv]4 ,new ,york3 ,john ,wiley & ,sons1 #ahhe4 ,,copp]?waite1 ,,william ,,*>les4 ,tunnel %ields & ! use ( compress$ air 9 subaque\s works4 ,new ,york3 ,d4 ,van ,no/r& ,company1 #aijf4 ,,dr9k]1 ,,h5ry ,,/urgess4 ,tunnel+1 explosive comp\nds & rock drills4 ,new ,york3 ,john ,wiley & ,sons1 #ahgh4 ,,latrobe1 ,,b5jam9 ,h4 ,report on ! ,hoosac ,tunnel 7,baltimore1 ,octob] #a1 #ahfb74 ,pp4 #abe-aci1 app4 #b1 9 ,report ( ! commission]s ^u ! ,troy & ,gre5field ,railroad & ,hoosac ,tunnel4 ,bo/on1 #ahfc4 ,,law1 ,,h5ry4 ,a memoir ( ! ,?ames ,tunnel4 ,weale's ,qu>t]ly ,pap]s on ,eng9e]+ 7,london1 #ahde-df71 vol4 #c1 pp4 #a-be & vol4 #e1 pp4 #a-hf4 ,! pneumatic tunnel "u ,broadway1 ,n4,y4 ,sci5tific ,am]ican 7,m>* #e1 #ahgj71 pp4 #aed-aef4 ,report ( ! commission]s ^u ! ,troy & ,gre5field ,railroad & ,hoosac ,tunnel to 8 excell5cy ! gov]nor & ! honorable ! executive c\ncil ( ! /ate ( ,massa*usetts1 ,febru>y #bh1 #ahfc4 ,bo/on1 #ahfc4 ,,/orr[1 ,,*>les ,s4 ,report on ,european tunnels 7,bo/on1 ,novemb] #bh1 #ahfb74 ,pp4 #e-abb1 app4 #a1 9 ,report ( ! commission]s ^u ! ,troy & ,gre5field ,railroad & ,hoosac ,tunnel4444 ,bo/on1 #ahfc4 ,! ,/4 ,clair ,tunnel4 ,eng9e]+ ,news 79 s]ies runn+ ,octob] #d to ,decemb] #bg1 #ahij74 ,,footnotes #a ,!re are two important second>y te*niques = op5+ subt]ranean & subaque\s ways1 nei!r a me?od truly ( tunnel+4 ,"o ( ^!1 ( anci5t orig91 us$ ma9ly 9 ! con/ruction ( %all[ subways & utility ways1 is ! cut & cov] sy/em1 :]eby an op5 tr5* is excavat$ & !n ro($ ov]4 ,! result is1 9 effect1 a tunnel4 ,! concept ( ! o!r me?od 0 prop\nd$ 9 ! e>ly #ai? c5tury b only us$ practically 9 rec5t ye>s4 ,?is is ! tr5* me?od1 a sort ( subaque\s equival5t ( cut & cov]4 ,a tr5* is dr$g$ 9 ! b$ ( a body ( wat]1 into :i* prefabricat$ sections ( l>ge diamet] tube are l[]$1 9 a cont9u\s l9e4 ,! jo9ts are !n seal$ by div]s1 ! tr5* is backfill$ ov] ! tube1 ! ends are br\ght up to dryl& portals1 ! wat] is pump$ out1 & a subt]ranean passage results4 ,! ,*esapeake ,bay ,bridge ,tunnel 7#aifj-aifd7 is a rec5t major "w ( ?is "*4 #b ,9 #aieb a successful ma*9e 0 develop$ on ?is plan1 ) h>d5$ roll]s on a revolv+ cutt+ head = dis9tegrat+ ! rock4 ,! idea is basically s\nd1 possess+ advantages 9 c]ta9 situations ov] conv5tional drill+ & bla/+ sy/ems4 #c ,9 #ahjg ! not$ ,corni% eng9e] ,trevi?ick comm5c$ a small timb]$ drift b5ea? ! ,?ames1 #e feet by #c feet1 z an exploratory passage = a l>g] vehicul> tunnel4 ,due to ! small frontal area1 he 0 able to successfully probe ab\t #ajjj feet1 b ! riv] !n broke 9 & halt$ ! "w4 ,m9e tunnels _h also rea*$ b5ea? ! ,iri% ,sea & v>i\s riv]s 9 ! coal regions ( ,newca/le1 b ^! 7 s f> bel[ ! surface z to be 9 p]fectly solid gr\nd & c h>dly be consid]$ subaque\s work+s4 #d ,unlike ! ,brunel tunnel1 ?is 0 driv5 f bo? ends simultane\sly1 ! total ov]all progress ?us be+ #c feet p] %ift r ?an #ah in*es4 ,a top spe$ ( #i feet p] day c\ld be advanc$ by ea* %ield "u ideal conditions4 #e ,ideally1 ! pressure ( air )9 ! "w area ( a pneumatically driv5 tunnel %\ld j balance ! hydro/atic head ( ! wat] )\t1 :i* is a function ( its total height above ! op5+4 ,if ! air pressure is n high en\gh1 wat] w1 ( c\rse1 ent]1 & if v l[1 !re is dang] ( complete collapse ( ! unsupport$ gr\nd areas4 ,if too high1 ! air pressure w ov]come t due to ! wat] & ! air w =ce its way out ?r\gh ! gr\nd1 ?r\gh increas+ly l>g] op5+s1 until x all ru%es out sudd5ly 9 a bl[\t4 ,! pressuriz$ atmosph]e gone1 ! wat] !n is able to p\r 9 ?r\gh ! same op5+1 flood+ ! work+s4 ,,index ,agricola1 ,georgius1 #bae1 #baf ,b>l[1 ,pet] ,w41 #bba1 #bbg ,bea*1 ,alfr$ ,ely1 #bbd1 #bbg-bbi1 #bca1 #bcg ,brunel1 ,m>c ,isamb>d 7! eld]71 #bjd1 #bje1 #bag1 #bah1 #bba1 #bbd1 #bbi1 #bca1 #bcf ,burleigh1 ,*>les1 #bab1 #bac ,burleigh ,rock ,drill ,company1 #bab ,burr1 ,s4 ,d4 ,v41 #bcf ,co*rane1 ,sir ,?omas1 #bca1 #bcb ,copp]?waite1 ,william ,*>les1 #bbd ,doane1 ,?omas1 #baj1 #bab1 #bac1 #bae ,dr9k]1 ,h5ry ,s41 #bbd1 #bcg ,grea!ad1 ,james ,h5ry1 #bjd1 #bah1 #bba1 #bbd1 #bbi1 #bca1 #bce-bcg ,gwynn1 ,/u>t1 #baj ,hask91 ,de,witt ,c41 #bjd1 #bcb1 #bcd-bcf ,haupt1 ,h]man1 #bjd1 #bji1 #baj ,hobson1 ,joseph1 #bcg ,latrobe1 ,b5jam9 ,h41 #bjh1 #bji ,law1 ,h5ry1 #bah ,m[bray1 ,george ,w41 #bac1 #bae ,nobel1 ,alfr$ ,b41 #bac ,putnam ,ma*9e ,works1 #bab ,%anley1 ,walt]1 #bab ,%anley ,bros41 #bae ,sommeill]1 ,g]ma91 #baj ,/orr[1 ,*>les ,s41 #baj ,twe$1 ,william ,m>cy 7,boss71 #bbi ,weale1 ,john1 #bah 99 99 99 99 99 ,transcrib]'s ,notes ,all obvi\s typographical errors correct$4 ,=matt+ inconsi/ancies & spell+ 7 /&>diz$4 ,p>agraphs split by illu/rations 7 rejo9$4 ,! text 9 ! reproduc$ h&bill = ! ,?ames ,tunnel 0 transcrib$ ) a slight modification to ! figure description portion4 ,! ,index 0 extract$ f ! full publication ,index4