,,am]ican ,,society ,,( ,,civil ,,eng9e]s ,,in/itut$ #aheb ,,transactions ,pap] ,no4 #aaei ,,! ,,new ,,york ,,tunnel ,,ext5sion ,,( ,,! ,,p5nsylvania ,,railroad4 ,,! ,,ea/ ,,riv] ,,tunnels4,a ,,by ,,james ,h4 ,,brace1 ,,francis ,,mason1 ,,& ,s4 ,h4 ,,wood>d1 ,,memb]s1 ,,am4 ,,soc4 ,c4 ,e4 ,?is pap] w be limit$ to a consid]ation ( ! con/ruction ( ! tunnels1 ! broad] que/ions ( design1 etc41 hav+ already be5 consid]$ 9 pap]s by ,brig4-,g54 ,*>les ,w4 ,raymond1 ,m4 ,am4 ,soc4 ,c4 ,e41 & ,alfr$ ,noble1 ,pa/-,presid5t1 ,am4 ,soc4 ,c4 ,e4 ,! location ( ! section ( ! "w to be consid]$ "h is %[n on ,plate ,,xiii ( ,mr4 ,noble's pap]4 ,!re are two p]man5t %afts on ea* side ( ! ,ea/ ,riv] & f\r s+le ca/-iron tube tunnels1 ea* ab\t #f1jjj ft4 long1 & consi/+ ( #c1ijj ft4 betwe5 %afts "u ! riv]1 & #b1jjj ft4 9 ,long ,isl& ,city1 mo/ly "u ! depot & pass5g] y>d ( ! ,long ,isl& ,railroad4 ,?is tube-tunnel "w 0 naturally a s+le job4 ,! contract = its con/ruction 0 let to ,s4 ,pe>son & ,son1 ,incorporat$1 gr\nd be+ brok5 on ,may #ag?1 #aijd4 ,five ye>s lat]1 to a day1 ! "w 0 f9i%$ & receiv$ its f9al inspection = acceptance by ! ,railroad ,company4 ,! contract 0 ( ! pr(it-%>+ type1 & requir$ an audit1 by ! ,railroad ,company1 ( ! contractor's books1 & a c>eful sy/em ( co/-keep+ by ! ,company's eng9e]s1 s t x is possible to include 9 ! foll[+ "s ( ! unit co/s ( ! "w4 ,^! are giv5 9 two p>ts3 ,! fir/ is call$ ! unit labor co/1 & is ! co/ ( ! labor 9 ! tunnel directly *>geable to ! ?+ consid]$4 ,x does n include ! labor ( op]at+ ! plant1 nor wat*m51 y>dm51 pipem51 & electricians4 ,! second is call$ top *>ges1 a common t]m1 b mean+ diff]5t ?+s to diff]5t contractors & eng9e]s4 ,"h1 x is made to include ! co/ ( ! contractor's /aff & rov+ labor]s1 su* z pipem51 electricians1 & y>dm51 ! co/ ( ! plant & its op]ation1 & all miscellane\s exp5ses1 b does n include any contractor's pr(it1 nor co/ ( mat]ials ent]+ p]man5t "w4 ,! contractor's plant is to be describ$ 9 a pap] by ,h5ry ,japp1,b ,m4 ,am4 ,soc4 ,c4 ,e41 & w n be dealt ) "h4 ,! contractors c>ri$ on _! "w f ?ree diff]5t sites4 ,f p]man5t %afts1 locat$ ne> ! riv] 9 ,manhattan1 f\r %ields 7 driv5 ea/w>d to ab\t ! middle ( ! riv]2 &1 f two simil> %afts at ! riv] front 9 ,long ,isl& ,city1 f\r %ields 7 driv5 we/w>d to meet ^? f ,manhattan4 ,f a tempor>y %aft1 ne> ,ea/ ,av5ue1 ,long ,isl& ,city1 ! l& section ( ab\t #b1jjj ft4 0 driv5 to ! riv] %afts4 ,footnote ,a3 ,pres5t$ at ! meet+ ( ,decemb] #ae?1 #aiji4 ,footnote ,b3 ,transactions1 ,am4 ,soc4 ,c4 ,e41 ,vol4 ,,lxix4 p4 #a4 ,,tunnels ,,f ,,ea/ ,,av5ue ,,to ,,! ,,riv] ,,%afts4 ,! s9k+ ( ! tempor>y %aft at ,ea/ ,av5ue 0 a fairly simple matt]4 ,r\gh #f by #ab-;94 %eet-pil+1 =m+ a rectangle1 #abg by #cd ft41 brac$ across by heavy timb]+1 0 driv5 ab\t #bh ft4 to rock z ! excavation progress$4 ,bel[ ?is1 ! %aft 0 sunk into rock1 ab\t #bg ft41 )\t timb]+4 ,z soon z ! %aft 0 d[n1 on ,septemb] #cj?1 #aijd1 bottom head+s 7 />t$ we/w>d 9 ,tunnels ,a1 ,b1 & ,d4 ,:5 ^! _h be5 driv5 ab\t half ! di/ance to ! riv] %afts1 s(t gr\nd 0 enc\nt]$4 7,see ,/ation #ei1 ,plate ,,xiii47 ,z ! gr\nd c>ri$ consid]able wat]1 x 0 decid$ to use compress$ air4 ,bulkheads 7 built 9 ! head+1 &1 ) an air pressure ( ab\t #ae lb4 p] sq4 941 ! head+ 0 driv5 ?r\gh ! s(t gr\nd & into rock by ord9>y m9+ me?ods4 ,! use ( compress$ air 0 !n discont9u$4 ,we/ ( ?is s(t gr\nd1 a top head+1 foll[$ by a b5*1 0 driv5 to ! s(t gr\nd at ab\t ,/ation #ff4 ,tunnel ,c1 be+ high]1 0 m 9 s(t gr\nd1 & at fir/ x 0 ! int5tion to delay its excavation until x _h be5 well dra9$ by ! bottom head+s 9 ! tunnels on ea* side4 ,a little lat] x 0 decid$ to use a %ield )\t compress$ air4 ,?is %ield _h be5 us$ 9 excavat+ ! /ations ( ! ,great ,nor!rn & ,city ,tunnel 9 ,london4 ,x 0 rebuilt1 its diamet] be+ *ang$ f #bd ft4 #h-a_/b 94 to #bc ft4 #e-a_/d 94 ,x prov$ too weak1 & aft] x _h flatt5$ ab\t #d 94 & _h be5 jack$ up ?ree times1 ! s*eme 0 ab&on$1 ! %ield 0 remov$1 & "w 0 cont9u$ by ! me?ods :i* 7 be+ us$ 9 ! o!r tunnels4 ,! %ield 0 r light1 b probably x w\ld h be5 /rong en\gh _h x be5 us$ ) compress$ air1 or _h ! mat]ial pass$ ?r\gh be5 all e>?4 ,"h1 !re 0 a n>r[ concrete cradle 9 ! bottom1 ) rock up to ab\t ! middle ( ! tunnel1 :i* 0 excavat$ to cle> ! %ield1 & gave no support on its sides4 ,! %ield 0 a cyl9d] cru%$ betwe5 =ces appli$ along ! top & bottom4 ,) ! exception ( ?is trial ( a %ield 9 ,tunnel ,c1 & a novel me?od 9 ,tunnel ,b1 :]e compress$ air1 b no %ield1 0 us$1 ! description ( ! "w 9 "o tunnel w d = all4 ,f ! bottom head+s break-ups 7 />t$ at sev]al places 9 ea* tunnel :]e !re 0 ample cov] ( rock above4 ,:]e ! ro( 0 9 s(t gr\nd1 top head+s 7 driv5 f ! po9ts ( break-up & timb]$4 ,z soon z ! full-siz$ excavation 0 complet$1 ! iron l9+ 0 built1 usually 9 %ort l5g?s4 ,x w be notic$ on ,plate ,,xiii t !re is a depression 9 ! rock betwe5 ,/ation #fe & ! riv] %afts1 leav+ all ! tunnels 9 s(t gr\nd4 ,z ?is 0 directly "u ! ,long ,isl& ,railroad pass5g] /ation1 x 0 ?\ght be/ to use a %ield & compress$ air4 ,?is 0 done 9 ,tunnels ,a1 ,c1 & ,d1 "o %ield be+ us$ successively = all ?ree4 ,x 0 fir/ erect$ 9 ,tunnel ,d at ,/ation #fd #dg4 ,f !re x 0 driv5 we/w>d to ! riv] %aft4 ,x 0 !n tak5 ap>t & re-erect$ 9 ,tunnel ,c at ,/ation #fc #fc & driv5 we/w>d to ! %aft4 ,x 0 !n f\nd t !re w\ld n be "t = "o %ield to d all f\r l9es4 ,! exp]i5ce 9 ,tunnels ,c & ,d _h prov5 ! gr\nd to be mu* bett] ?an _h be5 expect$4 ,!re 0 consid]able clay 9 ! s&1 &1 ) ! wat] bl[n out by compress$ air1 x 0 v /able4 ,a special timb]+ me?od 0 devis$1 & ,tunnel ,b 0 driv5 f ,/ation #ff #aj to ! %aft ) compress$ air1 b )\t a %ield4 ,9 ! meantime ! %ield 0 re-erect$ 9 ,tunnel ,a & 0 %ov$ ?r\gh ! s(t gr\nd f ,/ation #fe #dh ne>ly to ! riv] %aft1 :]e x 0 dismantl$4 ,!re 0 no?+ unusual ab\t ! %ield "w2 x 0 ab\t ! same z t "u ! riv]1 :i* is fully describ$ else:]e4 ,9 spite ( great c>e 9 excavat+ 9 front ( ! %ield1 & prompt gr\t+ beh9d x1 !re 0 a small settlem5t ( ! build+ above1 am\nt+ to ab\t #a-a_/b 94 9 ! walls & ab\t #e 94 9 ! gr\nd floors :i* 7 ( concrete laid l a sidewalk directly ^u ! gr\nd4 ,:e!r ?is settlem5t 0 due to gr\nd lo/ 9 ! %ield "w or to a compact+ ( ! gr\nd on acc\nt ( its be+ dri$ out by compress$ air1 x is impossible to say4 ,! int]e/+ features ( ?is "w f ,ea/ ,av5ue to ! riv] %afts are ! m9+ me?ods & ! build+ ( ! iron tube )\t a %ield4 ,,excavation ,,9 ,,all ,,rock4 ,:]e ! tunnel 0 all 9 good rock two di/9ct me?ods 7 us$4 ,! fir/ 0 ! bottom-head+-&-break-up1 & ! second1 ! top-head+-&-b5* me?od4 ,! fir/ is illu/rat$ by ,figs4 #a & #b1 ,plate ,,lxiii4 ,! bottom head+1 #ac ft4 wide & #i ft4 high1 hav+ fir/ be5 driv51 a break-up 0 />t$ by bla/+ d[n ! rock1 =m+ a *amb] ! full height ( ! tunnel4 ,! timb] plat=m1 %[n 9 ! draw+1 0 erect$ 9 ! bottom head+1 & ext5d$ ?r\gh ! break-up *amb]4 ,! plan 0 !n to drill ! entire face above ! bottom head+ & bla/ x d[n ^u ! timb] /ag+1 ?us ma9ta9+ a passage bel[ = ! traffic f ! head+ & break-ups f>!r d[n ! l9e4 ,/>t+ ) ! condition indicat$ by ,plate ,,xiii1 ! face 0 drill$1 ! columns 7 !n tak5 d[n & ! muck pile 0 %ovel$ ?r\gh holes 9 ! /ag+ into muck c>s bel[4 ,! face 0 !n bla/$ d[n ^u ! /ag+1 ! drill columns 7 set up on ! muck pile1 & ! op]ation 0 repeat$4 ,?is me?od has ! advantage t ! bottom head+ c be pu%$ ?r\gh rapidly1 & f x ! tunnel may be attack$ at a numb] ( po9ts at "o "t4 ,x 0 f\nd to be m exp5sive ?an ! top-head+-&-b5* me?od1 & z soon z ! depression 9 ! rock at ab\t ,/ation #ei 0 pass$1 a top head+ ab\t #g ft4 high1 & r\ghly ! segm5t ( a #bc-;ft4 circle1 0 driv5 to ! next s(t gr\nd 9 ea* ( ! f\r tunnels4 ,! rema9d] ( ! section 0 tak5 out 9 two b5*es1 ! fir/1 ab\t #d ft4 high1 0 kept ab\t #ae ft4 ahead ( ! l[] b5*1 :i* 0 ab\t ! rema9+ #aa ft4 high4 ,,excavation ,,9 ,,e>? ,,& ,,rock4 ,ab\t #b1ejj ft4 ( tunnel1 ! ro( ( :i* 0 9 s(t gr\nd1 0 excavat$ 9 normal air by ! m9+-&-timb]+ me?od4 ,9 ! great] "p ( ?is ! rock surface 0 well above ! middle ( ! tunnel4 ,! me?od ( timb]+ & m9+1 :ile well en\gh kn[n1 has n be5 g5]ally us$ 9 ! ,unit$ ,/ates4 ,illu/ration3 ,,plate ,,lxiii ,/>t+ f ! break-up 9 all rock1 z describ$ above1 & illu/rat$ on ,plate ,,xiii1 :5 s(t gr\nd 0 approa*$1 a top head+ 0 driv5 f ! rock into & ?r\gh ! e>?4 ,?is head+ 0 ab\t #g ft4 high & ab\t #f ft4 wide4 ,?is 0 done by ! usual po/1 cap1 & pol+-bo>d me?od4 ,! gr\nd 0 a runn+ s& ) little or no clay1 &1 at fir/1 consid]able wat]1 9 places4 ,all head+s requir$ side pol+s4 ,! ro( pol+ bo>ds 7 ab\t #b-a_/b or #c ft4 above ! outside limit ( ! tunnel l9+1 z illu/rat$ by ,figs4 #c1 #d1 & #e1 ,plate ,,lxiii4 ,! next /ep 0 to place two cr[n-b>s1 ,,aa1 usually ab\t #bj ft4 long1 "u ! caps4 ,po/s 7 !n plac$ "u ! b>s1 & pol+ bo>ds at "r angles to ! axis ( ! tunnel 7 !n driv5 out ov] ! b>s4 ,z ^! pol+s 7 be+ driv51 ! side pol+s ( ! orig9al head+ 7 remov$1 & ! e>? 0 m9$ out to ! end ( ^! new transv]se pol+s4 ,brea/ bo>ds 7 set on end "u ! ends ( ! transv]se pol+s :5 !y _h be5 driv5 out to _! limit4 ,side b>s1 ,,bb1 7 !n plac$ z f> out z possible & support$ on rak+ po/s4 ,^! po/s 7 c>ri$ d[n to rock1 if x 0 ne>1 if n1 a sill 0 plac$4 ,a new set ( transv]se pol+s 0 driv5 ov] ^! side b>s & ! process 0 repeat$ until ! sides _h be5 c>ri$ d[n to rock or d[n to ! elevation ( ! sills support+ ! po/s1 :i* 7 usually ab\t #d ft4 above ! axis ( ! tunnel4 ,! plan !n 0 to excavate ! rema9d] ( ! section & build ! iron l9+ 9 %ort l5g?s1 gradually transf]r+ ! weight ( ! ro( b>s ( ! iron l9+ z ! po/s 7 tak5 out4 ,?is meant t n m ?an f\r r+s1 & (t5 only "o r+1 c\ld be built be=e excavation & a %ort l5g? ( cradle became necess>y4 ,be=e ! po/s "u ! ro( b>s c\ld be built & ! weight transf]r$ to ! iron l9+1 a gr\t dam 0 plac$ at ! lead+ end ( ! iron l9+1 & gr\t 0 br\ght up to at lea/ #de f ! top4 ,su* work+s 7 9 progress at z _m z eight places 9 "o tunnel at ! same "t4 ,:]e !re 0 only ! ord9>y gr\nd-wat] to cont5d )1 ! driv+ ( ! top head+ dra9$ ! gr\nd v ?or\ghly1 & ! enl>g+ 0 done easily & )\t a s]i\s loss ( gr\nd4 ,"u ^! conditions ! surface settlem5t 0 f #f 94 to #b ft4 ,"u ,bord5 ,av5ue1 !re 0 m wat]1 :i* probably came f a leaky sew]2 x 0 n en\gh to =m a /ream1 b j kept ! gr\nd ?or\ghly saturat$4 ,!re 0 a cont9u$ ?\gh h>dly p]ceptible fl[ ( e>? ?r\gh e crevice 9 ! timb]+ dur+ ! six or eight weeks betwe5 ! driv+ ( ! top head+ & ! plac+ ( ! iron l9+2 & "h !re 0 a settlem5t ( f #d to #h ft4 at ! surface4 ,,tunnel+ ,,9 ,,compress$ ,,air ,,)\t ,a ,,%ield4 ,:5 x became evid5t t !re w\ld n be "t = "o %ield to d ! s(t gr\nd portions ( all f\r tunnels "u ! ,long ,isl& ,railroad /ation1 a plan 0 adopt$ & us$ 9 ,tunnel ,b :i*1 :ile n z rapid1 turn$ out to be z *eap z ! "w done by ! %ields4 ,figs4 #f & #g1 ,plate ,,lxiii1 & ,fig4 #a1 ,plate ,,lxiv1 illu/rate ?is "w fairly well4 ,! op]ation ( ?is s*eme 0 ab\t z foll[s3 ,hav+ ! iron built up to ! face ( ! full-siz$ excavation1 a hole or top head+1 ab\t #c ft4 wide & #d or #e ft4 high1 0 excavat$ to ab\t #aj ft4 9 advance4 ,?is 0 done 9 a few h\rs )\t timb]+ ( any k9d2 b1 z soon z ! hole or head+ 0 #aj ft4 out1 #f by #ab-;94 lagg+s or pol+s 7 put up 9 ! ro(1 ) ! re> ends re/+ on ! iron l9+ & ! lead+ ends re/+ on v]tical brea/ bo>ds4 ,! head+ 0 !n wid5$ out rapidly & ! lagg+ 0 plac$1 d[n to ab\t #de f ! cr[n4 ,! =w>d ends ( ! lagg+s 7 !n support$ by a timb] rib & sill4 ,protect$ by ?is ro(1 ! full section 0 excavat$1 & ?ree r+s ( ! iron l9+ 7 built & gr\t$1 & !n ! :ole process 0 repeat$4 ,illu/ration3 ,,plate ,,lxiv1 ,,fig4 #a4--,,tunnel+ ,,9 ,,compress$ ,,air ,,)\t ,,%ield4 ,illu/ration3 ,,plate ,,lxiv1 ,,fig4 #b4--,t-,,head ,,air-,,lock4 ,illu/ration3 ,,plate ,,lxiv1 ,,fig4 #c4--;,,cutt+ ,,edge ,,( ,,caisson ,,assembl$4 ,illu/ration3 ,,plate ,,lxiv1 ,,fig4 #d4--;,,caisson ,,support$ ,,on ,,jacks ,,& ,,blocks4 ,,concrete ,,cradles1 ,,h&-,,pack$ ,,/one ,,& ,,gr\t+4 ,_h ! ,ea/ ,av5ue ,tunnel be5 built by %ields1 z 0 contemplat$ at ! "t ( its design1 ! space betwe5 ! limits ( excavation & ! iron l9+ w\ld h be5 some:at less ?an by ! me?od actually us$1 especially 9 ! e>? portions4 ,?is space w\ld h be5 fill$ ) gr\t eject$ ?r\gh ! iron l9+4 ,! *ange 9 ! me?od ( do+ ! "w p]mitt$ ! use ( *eap] mat]ial1 9 place ( "p ( ! gr\t1 &1 at ! same "t1 facilitat$ ! "w4 ,! tube ( ca/-iron r+s is adapt$ to be built 9 ! tail ( ! %ield4 ,:]e no %ield 0 us$1 aft] ! excavation 0 complet$ & all loose rock 0 remov$1 timb]s 7 fix$ across ! tunnel f :i* semicircul> ribs 7 hung1 bel[ :i* lagg+ 0 plac$4 ,! space betwe5 ?is & ! r\gh rock surface 0 fill$ ) concrete4 ,?is =m$ a cradle 9 :i* ! iron tube c\ld be erect$1 &1 at ! same "t1 occupi$ space :i* w\ld h be5 fill$ by gr\t1 at great] co/1 _h a %ield be5 us$4 ,z soon z ea* r+ ( iron 0 erect$1 ! space betwe5 x & ! ro( ( ! excavation 0 fill$ ) h&-pack$ /one4 ,at ab\t e six? r+ a wall ( /one laid 9 mort> 0 built betwe5 ! l9+ & ! rock to s]ve z a dam to reta9 gr\t4 ,! int]/ices betwe5 ! h&-pack$ /ones 7 !n fill$ ) #a to #a gr\t ( cem5t & s&1 eject$ ?r\gh ! iron l9+4 ,! concrete cradles av]ag$ #a4je cu4 yd4 p] ft4 ( tunnel1 & co/1 exclusive ( mat]ials1 #f4gj p] cu4 yd41 ( :i* #b4be 0 = labor & #d4de 0 = top *>ges4 ,! h&-pack$ /one av]ag$ #a-a_/b cu4 yd4 p] ft4 ( tunnel1 & co/ #b4db p] cu4 yd41 ( :i* #j4ih 0 = labor & #a4dd 0 = top *>ges4 ,,erection ,,( ,,iron ,,l9+4 ,! contractors plann$ to erect ! iron l9+ ) erectors ( ! same patt]n z t us$ on ! %ield "u ! riv]1 m\nt$ on a travel+ /age4 ,^! w be describ$ 9 detail 9 ,mr4 ,japp's pap]4 ,two ( ^! /ages & erectors work$ 9 ea* tunnel at diff]5t po9ts4 ,! tunnel 0 attack$ f s _m po9ts t ^! erectors c\ld n be mov$ f work+ to work+4 ,! result 0 t ab\t #eh ( ! l9+ 0 built by h&4 ,at fir/ ?\ght1 ?is seems to be a crude & extravagant me?od1 z ! plates weigh$ ab\t #a ton ea* & ab\t #bj1jjj 7 erect$ by h&4 ,z x turn$ out1 ! co/ 0 n great] ?an = ^? erect$ by ma*9]y1 tak+ into acc\nt ! co/ ( erectors & p[]4 ,?is1 h[ev]1 0 l>gely because ! h& erection r$uc$ ! am\nt ( "w to be done by ! ma*9es s mu* t ! ma*9es _h an undue plant *>ge4 ,! h& erection 0 v simple4 ,a portable h&-w9*1 ) a #c_/h-;94 wire rope1 0 set 9 any conv5i5t place4 ,! wire rope 0 c>ri$ to a snat*-block fa/5$ to ! top ( ! iron previ\sly built2 or1 :]e ! ro( 0 9 s(t gr\nd1 ! timb]+ furni%$ po9ts ( atta*m5t4 ,! end ( ! wire rope 0 !n hook$ to a bolt hole 9 a new plate1 two m5 at ! w9* lift$ ! plate1 & ?ree or f\r o!rs swung x into approximate place1 &1 ) ! aid ( b>s & drift-p9s1 coax$ x into position & bolt$ x4 ,:]e !re 0 no timb]+ above ! iron1 sometimes ! key & adjo9+ plates 7 set on block+ on a timb] /ag+ & !n jack$ up to place4 ,,long ,,isl& ,,%afts4 ,! riv] %afts 7 design$ to s]ve bo? z work+ %afts & z p]man5t op5+s to ! tunnels1 & 7 l>g] & m sub/antial ?an w\ld h be5 requir$ = con/ruction purposes4 ,plate ,x ( ,mr4 ,noble's pap] %[s _! design4 ,!y consi/ ( two /eel caissons1 ea* #dj by #gd ft4 9 plan1 ) walls #e ft4 ?ick fill$ ) concrete4 ,a wall #f ft4 ?ick sep>at$ ea* %aft into two wells #bi by #cj ft41 ea* directly ov] a tunnel4 ,circul> op5+s = ! tunnel1 #be ft4 9 diamet]1 7 provid$ 9 ! sides ( ! caissons4 ,dur+ ! s9k+ ^! 7 clos$ by bulkheads ( /eel plates back$ by horizontal /eel gird]s4 ,! %afts 7 sunk z pneumatic caissons to a dep? ( #gh ft4 bel[ mean high wat]4 ,!re h be5 a few caissons :i* 7 l>g] & 7 sunk deep] ?an ^!1 b mo/ l>ge caissons h be5 = f\ndations1 su* z bridge pi]s1 & h be5 /opp$ at or a little bel[ ! surface ( ! rock4 ,! unusual feature ( ! caissons = ! ,long ,isl& %aft is t !y 7 sunk #ed ft4 ?r\gh rock4 ,x _h be5 hop$ t ! rock w\ld prove s\nd en\gh to p]mit /opp+ ! caissons at or a little bel[ ! surface & cont9u+ ! excavation )\t s9k+ !m fur!r2 = ?is reason only ! /eel = ! l[] #dj ft4 ( ! caissons 0 ord]$ at fir/4 ,! ro( ( ! work+ *amb] 0 plac$ #g ft4 above ! cutt+ edge4 ,x 0 a /eel floor1 design$ by ! contractors1 & consi/$ ( five /eel gird]s1 #f ft4 deep1 #bi ft4 long1 & spac$ at #e-;ft4 c5t]s4 ,betwe5 7 plates curv$ upw>d to a radius ( #d ft4 ,ea* work+ *amb] _h two %afts1 #c ft4 by #e ft4 9 cross-section1 ) a diaphragm divid+ x into two passages1 ! small] = m5 & ! l>g] = muck buckets4 ,on top ( ^! %afts 7 ,moran locks4 ,m\nt$ on top ( ! caisson 0 a #e-ton ,wilson crane1 :i* w\ld rea* ea* %aft & also ! muck c>s /&+ on tracks on ! gr\nd level beside ! caissons4 ,circul> /eel buckets1 #b ft4 #f 94 9 diamet] & #c ft4 high1 7 us$ = h&l+ all muck4 ,^! 7 tak5 f ! bottom ( ! work+ *amb]1 dump$ 9 c>s1 & return$ to ! bottom )\t unhook+4 ,"w 0 c>ri$ on by ?ree #h-;h\r %ifts p] day4 ,! e>? excavation 0 done at ! rate ( ab\t #fg cu4 yd4 p] day f "o caisson4 ,! rock excavation1 am\nt+ to ab\t #f1bjj cu4 yd4 9 ea* caisson1 0 done at ! rate ( ab\t #dd4e cu4 yd4 p] day4 ,! av]age rate ( l[]+1 :5 ! cutt+ edge ( ! s\? caisson 0 pass+ ?r\gh e>?1 0 #j4g ft4 p] day4 ,9 rock1 ! rate 0 #j4dh ft4 p] day 9 ! s\? caisson1 & #j4ci ft4 p] day 9 ! nor? caisson4 ,at ! beg9n+ all l[]+ 0 done ) sixte5 hydraulic jacks4 ,tempor>y brackets 7 fa/5$ to ! outside ( ! caisson4 ,a #ajj-ton hydraulic jack 0 plac$ "u ea* alt]nate bracket & "u ea* ( ! o!rs !re 0 block+4 ,! jacks 7 connect$ to a high-pressure pump 9 ! p[]-h\se4 ,z ! jacks lift$ ! caisson1 ! block+ 0 set = a l[] position1 to :i* ! caisson settl$ z ! jacks 7 exhau/$4 ,aft] ! caisson _h p5etrat$ ! e>? ab\t #aj ft41 ! outside brackets 7 remov$ & ! l[]+ 0 regulat$ by block+ plac$ "u brackets 9 ! work+ *amb]4 ,! caisson usually re/$ on ?ree sets ( block+s on ea* side & two on ea* end4 ,! block+ 0 ab\t #d ft4 inside ! cutt+ edge4 ,9 ! rock1 z ! cutt+ edge 0 cle>$ = a l[]+ ( ab\t #b ft41 #f by #h-;94 oak po/s 7 plac$ "u ! cutt+-edge angle4 ,:5 a suffici5t numb] ( po/s _h be5 plac$1 ! block+ on :i* ! caisson _h re/$ 0 knock$ or bla/$ out1 & ! rock und]nea? 0 excavat$4 ,! block+ 0 !n re-set at a l[] elevation4 ,! po/s "u ! cutt+ edge 7 !n *opp$ "p way ?r\gh & ! air pressure 0 l[]$ ab\t #aj lb41 :i* increas$ ! net weight to m ?an #d1jjj1jjj lb4 ,! po/s !n gradually cru%$ & ! caissons settl$ to ! new block+4 ,! tilt or level ( ! caisson 0 controll$ by *opp+ ! po/s m on ! side :i* 0 desir$ to move fir/4 ,! caisson ne>ly always c>ri$ a v l>ge net weight1 usually ab\t #hgj tons4 ,! concrete 9 ! walls1 :i* 0 add$ z ! caisson 0 be+ sunk1 0 kept at ab\t ! elevation ( ! gr\nd4 ,!re 0 g5]ally a dep? ( f #e to #bj ft4 ( wat] balla/ on top ( ! ro( ( ! work+ *amb]4 ,! air pressure 9 ! work+ *amb] 0 usually mu* less ?an ! hydro/atic head outside ! caisson4 ,= example1 ! av]age air pressure 9 ! s\? caisson dur+ ,janu>y1 #aijf1 0 #af-a_/b lb41 :ile ! av]age head 0 #fb4e ft41 equival5t to #bg lb4 p] sq4 94 ,"u ^! conditions1 !re 0 a cont9u$ b small leakage into ! caisson ( f #ae1jjj to #bj1jjj gal4 p] day4 ,9 ! rock ! excavation 0 always c>ri$ f #b to #e 94 outside ! cutt+ edge4 ,z soon z ! cutt+ edge 0 cle>$1 bags ( clay 7 plac$ "u x 9 a well-ti]$1 solid pile1 s t :5 ! caisson 0 l[]$ ! bags 7 cut ?r\gh & mo/ ( ! clay1 bags & all1 0 squeez$ back ( ! cutt+ edge betwe5 ! rock & ! caisson4 ,table #a %[s ! relation ( ! f9al position ( ! caissons to t design$4 ,! co/ ( rock excavation 9 ! caisson 0 #d4dh p] cu4 yd4 = labor & #aj4ed = top *>ges4 ,! bottom ( ! %aft is an inv]t$ concrete ar*1 #d ft4 ?ick1 wat]-pro($ ) #f-ply felt & pit*4 ,z soon z ! caisson 0 d[n to its f9al position & ! excavation 0 complet$1 concrete 0 deposit$ on ! unev5 rock surfaces1 br\ght up to ! l9e ( ! wat]-pro(+1 & giv5 a smoo? #a-;94 mort> coat4 ,! felt 0 /uck toge!r 9 #c-ply mats on ! surface ) hot coal-t> pit*4 ,^! 7 roll$ & s5t d[n into ! work+ *amb]1 :]e !y 7 put d[n ) cold pit* liquid at #fj ,fahr4 ,ea* %eet ( felt ov]lapp$ ! "o bel[ #f 94 ,! wat]-pro(+ 0 cov]$ by a #a-;94 mort> pla/] coat1 aft] :i* ! concrete ( ! #d-;ft4 inv]t$ ar* 0 plac$4 ,:ile ! wat]-pro(+ & concret+ 7 be+ done1 ! air pressure 0 kept at f #cj to #cc lb4 p] sq4 941 ! full hydro/atic head at ! cutt+ edge4 ,aft] /&+ = t5 days1 ! air pressure 0 tak5 (f1 & ! removal ( ! ro( ( ! work+ *amb] 0 begun4 ,! wat]-pro(+ 0 done by ! ,union ,con/ruction & ,wat]pro(+ ,company4 ,,table #a4--,,relation ,,( ,,! ,,f9al ,,position ,,( ,,! ,,caissons ,,to ,,t ,,design$4 ,,location4 ,,long ,,isl& ,,city4 ---------------------------------------- ------------------------ ,%aft4 ,nor?4 ,s\?4 ---------------------------------------- ------------------------ ,corn]4 ,high4 ,ea/4 ,nor?4 ,high4 ,ea/4 ,nor?4 ---------------------------------------- ------------------------ ,nor!a/#j4ba ft4#j4jh ft4#j4je ft4#j4cb ft4#j4ae ft4#j4bh ft4 ,nor?we/#j4bb #j4jh #j4jb #j4jj #j4ae #j4ab ,s\?we/#j4bg #j4ad #j4jb #j4ah #j4de #j4ab ,s\!a/#j4bc #j4ad #j4je #j4ci #j4de #j4bh ,,location4 ,,manhattan4 ---------------------------------------- ------------------------------------- ,%aft4 ,nor?4 ,s\?4 ---------------------------------------- ------------------------------------- ,corn]4 ,high4 ,ea/4 ,s\?4 ,high4 ,ea/ or ,we/4,nor? or ,s\?4 ---------------------------------------- ------------------------------------- ,nor!a/#j4bc ft4#j4gd ft4#j4ch ft4#j4jj ft4#j4jf ft4 ea/4#j4jd ft4 s\?4 ,nor?we/#j4jj #j4gd #j4bb #j4jh #j4jf #j4ac nor?4 ,s\?we/#j4aa #j4ca #j4bb #j4ba #j4de we/4#j4ac ,s\!a/#j4df #j4ca #j4ch #j4jd #j4de #j4jd s\?4 ,! co/ ( labor 9 compress$ air *>geable to concret+ 0 #c4dj p] cu4 yd4 ,aft] ! ro( ( ea* work+ *amb] _h be5 remov$1 ! %ield 0 erect$ on a timb] cradle 9 ! bottom ( ! %aft1 9 position to be %ov$ out ( ! op5+ 9 ! we/ side ( ! caisson4 ,tempor>y r+s ( iron l9+ 7 erect$ across ! %aft 9 ord] to furni% some?+ = ! %ield jacks to %ove aga9/4 ,! ro( ( ! work+ *amb] 0 !n re-erect$ ab\t #ce ft4 above its orig9al position & ab\t #h ft4 above ! tunnel op5+s4 ,?is "t1 in/ead ( ! two small %afts :i* 7 9 use dur+ ! s9k+ ( ! caisson1 a l>ge /eel %aft ) a ,t-head lock 0 built4 ,?is is illu/rat$ 9 ,fig4 #b1 ,plate ,,lxiv4 ,! %aft 0 #h ft4 9 diamet]4 ,inside !re 0 a ladd] & an elevator cage = l[]+ & hoi/+ m5 & ! /&>d #a-yd4 tunnel c>s4 ,at ! top1 =m+ ! head ( ! ,t1 !re 7 two /&>d tunnel locks4 ,,manhattan ,,%afts4 ,a p]man5t %aft1 simil> to ! riv] %afts 9 ,long ,isl& ,city1 0 con/ruct$ at ,manhattan ov] ea* pair ( tunnels4 ,ea* %aft 0 locat$ across two l9es1 ) its long] axis transv]se to ! tunnels4 ,plate ,,xiii %[s _! relative positions4 ,!y 7 divid$ equally by a re9=c$ concrete p>tition wall transv]se to ! l9e ( ! tunnels4 ,on completion1 ! we/]n portions 7 turn$ ov] to ! contractor = ! cross-t[n tunnels = 8 exclusive use4 ,s\? ,%aft4--,"w on ! s\? %aft 0 />t$ on ,june #i?1 #aijd1 ) ! s9k+ ( a #af by #af-;ft4 te/ pit 9 ! c5t] ( ! s\? half ( ! s\? %aft1 :i* rea*$ dis9tegrat$ rock at a dep? ( ab\t #bj ft4 ,/>t+ 9 ,augu/1 ! full %aft area1 #gd by #dj ft41 0 tak5 out 9 an op5 untimb]$ cut to ! rock1 & a #bj by #ej-;ft4 %aft 0 sunk ?r\gh ! rock to tunnel grade1 leav+ a #aj or #ab-;ft4 b]m ar\nd x4 7,fig4 #a1 ,plate ,,lxx47 ,! erection ( ! caisson 0 />t$1 ab\t ! middle ( ,janu>y1 on ! rock b]m surr\nd+ ! #bj by #ej-;ft4 %aft & ab\t #ae ft4 bel[ ! surface4 ,fig4 #c1 ,plate ,,lxiv1 %[s ! cutt+ edge ( ! caisson assembl$4 ,! excavation ( ! small %aft _h %[n t h>d rock & only a v small quantity ( wat] w\ld be enc\nt]$1 & t ! caisson ne$ be sunk only a %ort di/ance bel[ ! rock surface4 ,!re=e1 no work+-*amb] ro( 0 provid$1 ! caisson 0 built to a height ( only #dj ft41 & ! circul> op5+s 7 p]man5tly clos$4 ,! assembl+ ( ! caisson took #b-a_/b mon?s1 & on ,april #b;d l[]+ 0 />t$4 ,inv]t$ brackets 7 bolt$ tempor>ily to ! cutt+-edge /iff5+ brackets1 & ! s9k+ 0 c>ri$ on by me?ods simil> to ^? us$ at ,long ,isl&4 ,! jacks & block+ support+ ! caisson are %[n 9 ,fig4 #d1 ,plate ,,lxiv4 ,z soon z ! cutt+ edge ent]$ ! rock1 :i* 0 drill$ ab\t #f 94 outside ( ! neat l9es1 ! space surr\nd+ ! caisson 0 back-fill$ ) clay & muck to /eady x & provide sk9 friction4 ,z ! friction increas$1 ! walls 7 fill$ ) concrete1 & z ! caisson sl[ly settl$1 x 0 *eck$ & guid$ by block+4 ,! cutt+ edge f9ally came to re/ #ca ft4 bel[ mean high wat]1 ! s9k+ hav+ be5 accompli%$ 9 ab\t sev5 weeks1 at an av]age rate ( #j4ej ft4 p] day4 ,! f9al position ( ! cutt+ edge 9 relation to its design$ position is %[n 9 ,table #a4 ,a b]m ab\t #d ft4 wide 0 left at ! foot ( ! caisson bel[ :i* ! rock 0 some:at fissur$ & requir$ timb]+4 ,! cutt+ edge ( ! caisson 0 seal$ to ! rock ) gr\t on ! outside & a concrete base to ! caisson walls on ! inside1 ! latt] re/+ on ! #d-;ft4 b]m4 ,foll[+ ! completion ( ! %aft1 ! p]man5t sump 0 excavat$ to grade = use dur+ con/ruction4 ,nor? ,%aft4--,! nor? %aft _h to be sunk 9 a v re/rict$ area4 ,! ea/ side ( ! caisson cle>$ an adjo9+ build+ at "o po9t by only #a ft41 :ile ! nor?we/ corn] 0 )9 ! same di/ance ( ! ea/ l9e ( ,fir/ ,av5ue4 ,z 9 ! case ( ! ,long ,isl& %afts1 ! /eelwork = only ! l[] #dj ft4 0 ord]$ at ! />t4 ,?is height 0 completely assembl$ be=e s9k+ 0 begun4 ,! caisson 0 l[]$ 9 ab\t ! same mann] z ^? previ\sly describ$4 ,! be>+ brackets = ! hydraulic jacks 7 atta*$1 z at ! s\? %aft1 to ! inside ( ! cutt+-edge brackets4 ,! ea/ side ( ! caisson 0 9 contact ) ! f\ndations ( ! neighbor+ build+1 :ile ! we/ side 0 9 mu* s(t] mat]ial4 ,z a consequ5ce1 ! we/ side t5d$ to settle m rapidly & ?us ?r[ ! caisson out ( level & position4 ,to c\nt]act t t5d5cy1 x 0 necess>y to load ! ea/ wall heavily ) ca/-iron tunnel sections1 9 addition to ! concrete fill+ 9 ! walls4 ,soon aft] s9k+ 0 begun1 a small te/ %aft 0 sunk to a po9t bel[ ! elevation ( ! top ( ! tunnels4 ,! rock 0 f\nd to be s\nd1 h>d1 & ne>ly dry4 ,x 0 !n decid$ to /op ! caisson z soon z a f\ndation c\ld be secur$ on s\nd rock4 ,! latt] 0 f\nd at a dep? ( #ch ft4 bel[ mean high wat]4 ,) ! cutt+ edge seat$ at t dep?1 ! top ( ! caisson 0 only #b ft4 above mean high wat]1 & z ?is 0 insuffici5t protection aga9/ high tides1 a #aj-;ft4 ext5sion 0 ord]$ = ! top4 ,"w1 h[ev]1 w5t on )\t delay on ! rema9d] ( ! excavation4 ,! junction betwe5 ! cutt+ edge & ! rock 0 seal$ ) concrete & gr\t4 ,! caisson 0 l[]$ at an av]age rate ( #j4ec ft4 p] day4 ,! size ( ! %aft bel[ ! cutt+ edge 0 #fb ft4 #g 94 by #cb ft4 ,! av]age rate ( excavation dur+ ! s9k+ 9 s(t mat]ial 0 #hd cu4 yd4 p] day4 ,! av]age rate ( rock excavation bel[ ! f9al position ( ! cutt+ edge 0 #abe cu4 yd4 p] day4 ,!re 7 night & day %ifts1 ea* work+ #aj h\rs4 ,excavation 9 e>? co/ #c4if p] cu4 yd41 ( :i* #a4de 0 = labor & #b4ea = top *>ges1 etc4 ,! excavation ( rock co/ #h4ic p] cu4 yd41 #b4hc be+ = labor & #f4aj = top *>ges4 ,! f9al elevations ( ! f\r corn]s ( ! cutt+ edge1 toge!r ) _! displacem5t f ! desir$ positions1 are %[n 9 ,table #a4 ,,riv] ,,tunnels4 ,! f\r riv] tunnels1 betwe5 ! ,manhattan & ,long ,isl& ,city %afts1 a di/ance ( ab\t #c1ijj ft41 7 con/ruct$ by ! %ield me?od4 ,eight %ields 7 erect$1 "o on ea* l9e 9 ea* %aft1 ! f\r f ,manhattan work+ ea/w>d to a junction ne> ! middle ( ! riv] ) ! f\r work+ we/w>d f ,long ,isl& ,city4 ,t[>d ! end ( ! "w x 0 evid5t t ! %ields 9 ,tunnels ,b1 ,c1 & ,d w\ld meet 9 ! s(t mat]ial a %ort di/ance ea/ ( ! ,blackwell's ,isl& ,reef if "w 7 cont9u$ 9 all head+s4 ,9 ord] t ! junction might be made 9 firm mat]ial1 "w f ,manhattan 9 ^? ?ree tunnels 0 susp5d$ :5 ! %ields rea*$ ! edge ( ! l$ge4 ,! %ields 9 ,tunnel ,a met at a correspond+ po9t )\t ! susp5sion ( "w 9 ei!r4 ,an av]age ( #a1gfj ft4 ( tunnel 0 driv5 f ,manhattan & #b1adb ft4 f ,long ,isl& ,city4 ,illu/ration3 ,,plate ,,lxv1 ,,fig4 #a4--,,%ield ,,fitt$ ,,) ,,sectional ,,slid+ ,,hoods ,,& ,,slid+ ,,ext5sions ,,to ,,! ,,floors4 ,illu/ration3 ,,plate ,,lxv1 ,,fig4 #b4--,,%ield ,,fitt$ ,,) ,,fix$ ,,hoods ,,& ,,fix$ ,,ext5sions ,,to ,,! ,,floors4 ,,tunnels ,,driv5 ,,ea/w>d ,,f ,,manhattan4 ,mat]ials & ,inception ( ,"w4--,! mat]ials enc\nt]$ are %[n 9 ! pr(ile on ,plate ,,xiii1 & 7 simil> 9 all ! tunnels4 ,9 g5]al1 !y 7 f\nd to be ab\t z indicat$ 9 ! prelim9>y bor+s4 ,! mat]ials met 9 ,tunnel ,a may be tak5 z typical ( all4 ,f ! ,manhattan %aft ea/w>d1 9 succession1 !re 7 #abc ft4 ( all-rock section1 #hg ft4 ( "p e>? & "p rock1 #gbc ft4 ( all e>?1 #eae ft4 ( "p rock & "p e>?1 #bia ft4 ( all rock1 & #ef ft4 ( "p rock & "p e>?4 ,! rock on ! ,manhattan side 0 ,hudson s*i/1 :ile t 9 ! reef 0 ,=dham gneiss4 ,"h1 z else:]e1 !y resembl$ ea* o!r closely2 ! gneiss 0 slightly ! h>d]1 b bo? 7 badly seam$ & fissur$4 ,:]ev] x 0 enc\nt]$ 9 ?is "w1 ! rock surface 0 cov]$ by a deposit ( b\ld]s1 gravel1 & s&1 v>y+ 9 ?ickness f #d to #aj ft4 & av]ag+ ab\t #f ft4 ,! slope ( ! surface ( ! l$ge on ! ,manhattan side av]ag$ ab\t #a v]tical to #d horizontal4 ,! rock ne> ! surface 0 full ( dis9tegrat$ seams1 & 0 badly brok5 up4 ,x 0 irregul>ly /ratifi$1 & dipp$ t[>d ! we/ at an angle ( ab\t #fj degrees4 ,l>ge pieces frequ5tly broke f ! face & slid into ! %ield1 (t5 expos+ ! s&4 ,! rock surface 0 v irregul>1 & 0 cov]$ ) b\ld]s & deta*$ masses ( rock emb$d$ 9 co>se s& & gravel4 ,! s& & gravel all[$ ! air to escape freely4 ,by ! "t ! %ields _h entirely cle>$ ! rock1 ! mat]ial 9 ! face _h *ang$ to a f9e s&1 /ratifi$ e few in*es by v ?9 lay]s ( *ocolate-color$ clayey mat]ial4 ,?is is ! mat]ial else:]e ref]r$ to z quicks&4 ,z ! %ield advanc$ ea/w>d1 ! numb] & ?ickness ( ! lay]s ( clay increas$ until ! clay =m$ at lea/ #bj ( ! entire mass1 & _m ( ! lay]s 7 #b 94 ?ick4 ,at a di/ance ( ab\t #ddj ft4 beyond ! ,manhattan l$ge1 ! mat]ial at ! bottom ( ! face *ang$ sudd5ly to "o 9 :i* ! lay]s ( clay compos$ probably #ih ( ! :ole4 ,! s& lay]s 7 n m ?an #a_/af 94 ?ick & av]ag$ ab\t #b 94 ap>t4 ,! surface ( ! clay rose gradually = a di/ance ( #dj ft4 9 ,tunnels ,a & ,b1 & #ajj ft4 9 ,tunnels ,c & ,d1 :5 gravel & b\ld]s appe>$ at ! bottom ( ! %ield4 ,at t "t ! clay compos$ ab\t "o-half ( ! face4 ,! surfaces ( bo? ! clay & gravel 7 irregul>1 b !y rose gradually4 ,aft] rock 0 enc\nt]$1 ! =mations ( gravel & clay 7 r\ghly p>allel to ! rock surface4 ,z ! surface ( ! rock rose !y disappe>$ 9 ord] & 7 aga9 enc\nt]$ :5 ! %ields broke out ( rock on ! ea/ side ( ! ,blackwell's ,isl& ,reef4 ,ea/ ( ! reef a l>ge quantity ( co>se op5 s& 0 pres5t 9 ! gravel =mations be=e ! clay appe>$ bel[ ! top ( ! cutt+ edge4 ,9 ,tunnels ,c & ,d ?is 0 especially difficult to h&le4 ,x appe>s to be a reasonable assumption t ! lay] ( clay 0 cont9u\s across ! reef4 ,:]ev] ! clay ext5d$ above ! top ( ! %ield x r$uc$ ! escape ( air mat]ially4 ,x is d\btless l>gely due to ?is circum/ance t ! "p-rock sections 9 ! reef 7 n ! mo/ difficult portions ( ! "w4 ,:ile s9k+ ! l[] portions ( ! %afts ! tunnels 7 excavat$ ea/w>d 9 ! solid rock = a di/ance ( ab\t #fj ft41 :]e ! rock at ! top 0 f\nd to be some:at dis9tegrat$4 ,?is 0 z f> z x 0 consid]$ prud5t to g ) ! full-siz$ section )\t air pressure4 ,at ab\t ! same "t top head+s 7 excavat$ we/w>d f ! %afts = a di/ance ( #ajj ft41 & ! head+s 7 enl>g$ to full size = #ej ft4 ,! object 0 to avoid damage to ! %aft & int]f]5ce ) ! riv] tunnel :5 "w 0 />t$ by ! contractor = ! cross-t[n tunnel4 ,illu/ration3 ,,plate ,,lxvi1 ,,fig4 #a4--,,re> ,,( ,,%ield ,,%[+ ,,complete ,,fitt+s4 ,illu/ration3 ,,plate ,,lxvi1 ,,fig4 #b4--,,%ield ,,) ,,l[] ,,portion ,,( ,,bulkhead ,,remov$4 ,! %ields 7 erect$ on timb] cradles 9 ! %aft1 & 7 %ov$ =w>d to ! face ( ! excavation4 ,concrete bulkheads1 ) ! necess>y air-locks1 7 !n built across ! tunnels beh9d ! %ields4 ,! %ields 7 erect$ be=e ! divid+ walls betwe5 ! two contracts 7 plac$4 ,r+s ( iron tunnel l9+1 back$ by timb]s spann+ ! op5+s on ! we/ side1 7 erect$ tempor>ily across ! %afts 9 ord] to af=d a be>+ = ! %ield jacks :ile %ov+ into ! portals4 ,! movem5t ( ! %ield ea/w>d 0 cont9u$ 9 ea* tunnel = a di/ance ( ab\t #fj ft41 & ! p]man5t ca/-iron tunnel l9+ 0 erect$ z ! %ield advanc$4 ,be=e break+ out ( rock1 x 0 necess>y to h air pressure 9 ! tunnels4 ,?is requir$ ! build+ ( bulkheads ) air-locks inside ! ca/-iron l9+s j ea/ ( ! portals4 ,be=e erect+ ! bulkheads x 0 necess>y to close ! annul> space betwe5 ! iron tunnel l9+ & ! rock4 ,! space at ! portal 0 fill$ ) a concrete wall4 ,aft] ab\t tw5ty p]man5t r+s _h be5 erect$ 9 ea* tunnel1 two r+s 7 pull$ ap>t at ! tail ( ! %ield & a second masonry wall or dam 0 built4 ,! space betwe5 ! two dams 0 !n fill$ ) gr\t4 ,to avoid ! possibility ( pu%+ ! iron backw>d aft] ! air pressure 0 on1 r+s ( segm5tal plates1 #e_/h 94 ?ick & #ac-g_/h 94 wide1 7 ins]t$ 9 eighte5 circumf]5tial jo9ts 9 ea* tunnel betwe5 ! r+s z !y 7 erect$4 ,! plates conta9$ slott$ holes to mat* ^? 9 ! segm5ts4 ,aft] ! r+s left ! %ield1 ! plates 7 driv5 outw>d1 & project$ ab\t #e 94 ,:5 ! tunnel 0 gr\t$1 ! plates 7 emb$d$4 ,! bulkheads 7 complet$1 & ! tunnels 7 put "u air pressure on ! foll[+ dates3 ,l9e ,d1 on ,octob] #e?1 #aije2 ,l9e ,c1 on ,novemb] #f?1 #aije2 ,l9e ,b1 on ,novemb] #be?1 #aije2 ,l9e ,a1 on ,decemb] #a/1 #aije4 ,?is m>k$ ! end ( ! prep>atory p]iod4 ,9 ! deepe/ "p ( ! riv]1 ne> ! pi]-head l9e on ! ,manhattan side1 !re 0 only #h ft4 ( natural cov] ov] ! tops ( ! tunnels4 ,?is cov] consi/$ ( ! f9e s& previ\sly describ$1 & x 0 c]ta9 t ! air w\ld escape freely f ! tunnels ?r\gh x4 ,to give a great] dep? ( cov] & to *eck ! loss ( air1 ! contractor prep>$ to cov] ! l9es ( ! tunnels ) blankets ( clay1 :i*1 h[ev]1 _h be5 provid$ = 9 ! specifications4 ,p]mits1 z describ$ lat]1 7 obta9$ at diff]5t times f ! ,secret>y ( ,w>1 = dump+ clay 9 v>y+ ?icknesses ov] ! l9e ( "w4 ,! dump+ = ! blanket all[$ "u ! fir/ p]mit 0 complet$ 9 ,febru>y1 #aijf4 ,! ?ickness ( ?is blanket v>i$ consid]ably1 b av]ag$ #aj or #ab ft4 on ! ,manhattan side4 ,! orig9al blanket 0 ( mat]ial advantage1 b ! dep? ( clay 0 insuffici5t to /op ! loss ( air4 ,! ess5tial p>ts ( ! %ields 9 ! f\r tunnels 7 exactly alike4 ,^? 9 ,tunnels ,b & ,d1 h[ev]1 7 orig9ally fitt$ ) sectional slid+ hoods & slid+ ext5sions to ! floors ( ! work+ *amb]s1 z %[n by ,fig4 #a1 ,plate ,,lxv4 ,! %ields 9 ,tunnels ,a & ,c 7 orig9ally fitt$ ) fix$ hoods & fix$ ext5sions to ! floors1 z %[n 9 ,fig4 #b1 ,plate ,,lxv4 ,a full description ( ! %ields w be f\nd 9 ,mr4 ,japp's pap]4 ,! %ields 9 ea* pair ( tunnels 7 advanc$ ?r\gh ! solid rock section ab\t abrea/ ( ea* o!r1 until te/ holes f ! faces indicat$ s(t gr\nd )9 a few feet4 ,z ! di/ance betwe5 ! sides ( ! two tunnels 0 only #ad ft41 x 0 ?\ght be/ to let ,tunnels ,b & ,d ga9 a lead ( ab\t #ajj ft4 be=e ,tunnels ,a & ,c op5$ out into s(t gr\nd1 9 ord] t a bl[ f "o tunnel might n ext5d to ! o!r4 ,"w 9 ,tunnel ,c 0 %ut d[n on ,decemb] #bc;d1 #aije1 aft] expos+ s& to a dep? ( #c ft4 at ! top1 & x rema9$ clos$ = sev5 weeks4 ,"w 9 ,tunnel ,a 0 susp5d$ on ,septemb] #bi?1 #aije4 ,by ! "t ,tunnel ,b _h made ! requir$ advance1 x1 toge!r ) ,tunnels ,c & ,d1 0 ov]tax+ ! capacities ( ! compressor plant4 ,only a little "w 0 done 9 ,tunnel ,c until ,july1 #aijf1 & "w 9 ,tunnel ,a 0 n resum$ until ,octob] #bb;d1 #aijf4 ,,tunnels ,,driv5 ,,we/w>d ,,f ,,long ,,isl& ,,city4 ,mat]ials & ,inception ( ! ,"w4--,! mat]ials met 9 ,tunnel ,a are typical ( all f\r tunnels4 ,f ! ,long ,isl& %afts we/w>d1 9 succession1 !re 7 #abd ft4 ( all-rock section1 #abe ft4 ( "p rock & "p e>? section1 #bb ft4 ( all-rock section1 #ef ft4 ( "p rock & "p e>? section1 #chg ft4 ( all-rock section1 #gj ft4 ( "p e>? & "p rock section1 & #a1ccc ft4 ( all-e>? section4 ,illu/ration3 ,,plate ,,lxvii ,! mat]ials pass$ ?r\gh are indicat$ on ,plate ,,xiii4 ,! rock 0 simil> to t ( ! ,blackwell's ,isl& ,reef1 & 0 likewise cov]$ by a lay] ( s& & b\ld]s4 ,! rema9d] ( ! s(t gr\nd 0 divid$ into ?ree classes4 ,! fir/ 0 a v f9e r$ s&1 :i* occurr$ 9 a lay] v>y+ 9 ?ickness f #f ft4 to at lea/ #ae ft4 ,x may h be5 mu* deep] above ! tunnel4 ,x is ! quicks& usually enc\nt]$ 9 all deep f\ndations 9 ,new ,york ,city4 ,! foll[+ is ! result ( ! sift+ te/ ( ?is s&3 ,held on ,no4 #cj sieve #j4f ,pass$ ,no4 #cj1 ,no4 #dj #j4d ,no4 #dj1 ,no4 #ej #j4g ,no4 #ej1 ,no4 #fj #b4d ,no4 #fj1 ,no4 #hj #ad4i ,no4 #hj1 ,no4 #ajj #ed4j ,no4 #ajj1 ,no4 #bjj #h4j ,no4 #bjj #ai4j ------ #ajj4j ,?is means t gra9s ( all b #d ( x 7 less ?an #j4jjga 94 9 diamet]4 ,! #ai :i* pass$ ! ,no4 #bjj sieve1 ! gra9s ( :i* 7 #j4jjbf 94 or less 9 diamet]1 :5 obs]v$ ) a microscope appe>$ to be p]fectly clean gra9s ( qu>tz2 to ! eye x look$ l ord9>y build+ s&1 %>p1 & well grad$ f l>ge to small gra9s4 ,?is s&1 ) a surplus ( wat]1 0 quick4 ,) ! wat] bl[n out ( x by air pressure1 x is /able1 /&s up well1 & is v easy to "w4 ,x appe>s to be ! same z ! r$di% quicks& f\nd 9 mo/ deep excavations ar\nd ,new ,york ,city4 ,! second mat]ial 0 pron\nc$ bull's liv] by ! m9]s z soon z x 0 uncov]$4 ,bull's liv] seems to be a common t]m among ,engli%-speak+ m9]s ! _w ov]4 ,x is d\btful1 h[ev]1 if x is always appli$ to ! same ?+4 ,9 ?is case x consi/$ ( lay]s ( blue clay & v f9e r$ s&4 ,! clay seem$ to be p]fectly pure & entirely free f s&4 ,x w\ld break easily ) a clean1 almo/ cry/all9e1 fracture1 & yet x 0 s(t & w\ld "w up easily4 ,! lay]s ( clay v>i$ 9 ?ickness f #a_/af 94 to #a 941 :ile ! ?ickness ( ! s& lay] v>i$ f #a_/d 94 to sev]al in*es4 ,! s& 0 ! same z ! quicks& already describ$4 ,! bull's liv] 0 ideal mat]ial 9 :i* to "w a %ield4 ,x /ood up z well & held ! air ab\t z well z clay1 & 0 mu* easi] to h&le4 ,! ?ird mat]ial 0 a lay] ( f9e gray s& :i* 0 enc\nt]$ 9 ! top ( all ! tunnels = ab\t #djj ft4 j ea/ ( ,blackwell's ,isl& ,reef4 ,x 0 v op51 & _h gra9s ( r uni=m size4 ,dur+ ! />t+ out ( ! tunnels f ! %afts1 & = m ?an a ye> aft]w>d1 ! ro( ( ! work+ *amb] 9 ! caissons & ! locks previ\sly describ$ "u ! ,long ,isl& %afts took ! place ( ! bulkhead across ! tunnels = conf9+ ! air pressure4 ,! fir/ "w 9 air pressure 0 to remove ! %ield plug clos+ ! op5+ 9 ! side ( ! %aft4 ,?is be+ done1 ! %ield 0 %ov$ ?r\gh ! op5+1 & excavation begun4 ,at ! />t ! %ields 7 fitt$ ) movable plat=ms1 b no hoods ( any k9d 7 plac$ until aft] ! rock excavation 0 complet$4 ,,me?ods ,,( ,,excavation4 ,! di/ribution ( mat]ials to be excavat$1 z previ\sly outl9$1 divid$ ! excavation into ?ree di/9ct classes1 = :i* diff]5t me?ods _h to be develop$4 ,^! ?ree classes 73 ,fir/4--,all-rock section4 ,second4--,rock 9 ! bottom1 e>? 9 ! top4 ,?ird4--,all-e>? section4 ,! ext5t ( ! second & ?ird classes 0 mu* great] ?an t ( ! fir/1 & !y1 ( c\rse1 det]m9$ ! use ( ! %ield4 ,%ields _h n previ\sly be5 us$ ext5sively 9 rock "w1 ei!r :]e ! face 0 :olly or p>tly 9 rock1 & x 0 necess>y to develop ! me?ods by exp]i5ce4 ,! specifications requir$ t :]e rock 0 pres5t 9 ! bottom1 a b$ ( concrete %\ld be laid 9 ! =m ( a cradle on :i* to advance ! %ield4 ,all ,rock4--,at diff]5t times1 ?ree g5]al me?ods 7 us$ = excavat+ 9 all-rock sections4 ,!y may be call$3 ,! bottom-head+ me?od2 ! full-face me?od2 & ! c5t]-head+ me?od4 ,! bottom-head+ me?od 0 fir/ tri$4 ,a head+1 ab\t #h ft4 high & #ab ft4 wide1 0 driv5 on ! c5t] l9e1 ) its bottom z ne>ly z possible on ! grade l9e ( ! bottom ( ! tunnel4 ,x 0 drill$ 9 ! ord9>y mann] by f\r drills m\nt$ on two columns4 ,! face ( ! head+s v>i$ f #aj to #cj ft4 9 advance ( ! cutt+ edge4 ,aft] driv+ ! head+ = ab\t #aj ft41 ! bottom 0 cle>$ out & a concrete cradle 0 set4 ,! wid? ( ! cradles v>i$1 b 0 g5]ally f #h to #aj ft4 ,! excavation 0 enl>g$ to full size z ! %ield advanc$1 ! drills be+ m\nt$ 9 ! =w>d comp>tm5ts ( ! %ield1 z %[n by ,fig4 #a1 ,plate ,,lxvii1 :i* repres5ts ! conditions aft] ! op5+ _h be5 cut 9 ! bulkhead1 b be=e ! new me?ods1 m5tion$ lat]1 _h be5 develop$4 ,illu/ration3 ,,plate ,,lxviii ,! sides & top 7 %ot d[nw>d into ! head+4 ,! area ( ! face rema9+ beh9d ! head+ 0 l>ge1 & a great numb] ( holes & sev]al r\nds 7 requir$ to fire ! face to advantage4 ,z soon z fir+ 0 />t$ at ! face1 ! head+ 0 completely block$1 & op]ations !re _h to be susp5d$ until ! muck+ 0 ne>ly complet$4 ,! bottom-head+ me?od 0 probably z good z any t c\ld be devis$ = use ) ! %ields z orig9ally in/all$4 ,all ! muck _h to be tak5 f ! face by h& & h&l$ ?r\gh ! *utes or doors4 ,by drill+ f ! %ield1 "s muck 0 bla/$ on to ! ext5sions ( ! floors & c\ld be h&l$ f ! upp] comp>tm5ts4 ,at be/1 h[ev]1 ! %ield ) ! clos$ transv]se bulkhead 0 a s]i\s ob/acle to rapid "w 9 rock sections4 ,! full-face me?od 0 only us$ :]e ! rock 0 n consid]$ safe = a head+4 ,a cut 0 fir$ at ! bottom1 toge!r ) side holes1 9 a mann] q simil> to t adopt$ 9 ! fir/ set ( holes = a bottom head+4 ,! cradle 0 !n plac$1 9 l5g?s ( ei!r #b4e or #e ft41 aft] :i* ! rema9d] ( ! face 0 fir$ 9 ! same mann] z = ! bottom-head+ me?od4 ,! clos$ transv]se bulkhead ) air-locks1 z %[n 9 ,fig4 #a1 ,plate ,,lxvi1 0 plac$ 9 ! %ield 9 ! hope t x w\ld only be necess>y to ma9ta9 ! full air pressure 9 ! work+ comp>tm5ts 9 front ( ! bulkhead4 ,x 0 also ?\ght t "s =m ( bulkhead :i* c\ld be clos$ quickly & tightly w\ld be necess>y to prev5t flood+ ! tunnel 9 case ( bl[s4 ,:ile no attempt 0 ev] made to r$uce ! pressure beh9d ! %ield bulkhead1 x 0 obvi\s f ! exp]i5ce ) ,tunnels ,b & ,d1 :ile work+ 9 ! s& betwe5 ,manhattan & ! reef1 t ! plan 0 n practicable1 & t ! clos$ bulkhead 9 ! bottom 0 a h9drance in/ead ( a safegu>d4 ,z soon z rock 0 enc\nt]$ 9 ^? tunnels at ! we/ edge ( ! reef1 ! contractor cut ?r\gh ! bulkheads & alt]$ !m1 z %[n 9 ,fig4 #b1 ,plate ,,lxvi4 ,tak+ advantage ( ! exp]i5ce ga9$1 op5+s 7 cut ?r\gh ! bulkheads 9 ,%ields ,a & ,c1 :ile !y 7 %ut d[n ne> ! edge ( ! ,manhattan l$ge4 ,9 erect+ ! %ields at ,long ,isl& ,city 9 ,may & ,june1 #aijf1 op5+s 7 also provid$4 ,^! %ields _h to pass ?r\gh ab\t #gjj ft4 ( rock at ! />t1 ! great] portion ( :i* 0 all-rock section4 ,x 0 at t po9t t op5+s 7 fir/ us$ ext5sively & me?ods 7 develop$1 :i* w\ld n h be5 possible except :]e e>s c\ld be pass$ ?r\gh ! %ield4 ,! bottom-head+ me?od 0 fir/ tri$1 b ! work+ space 9 front ( ! %ield 0 cramp$1 & b few m5 c\ld be employ$ 9 load+ ! c>s4 ,to give m room1 ! head+ 0 gradually wid5$4 ,! enl>gem5t at ! top1 :5 made f ! %ield1 block$ all "w at ! face ( ! head+ :ile ! =m] op]ation 0 9 progress4 ,to r$uce ! delays1 ! head+ 0 rais$1 ?us r$uc+ ! quantity ( rock left 9 ! top1 & ! bottom 0 tak5 out z a b5*4 ,to avoid block+ ! tracks :5 fir+ ! top1 a heavy timb] plat=m 0 built out f ! floors ( ! middle work+ comp>tm5ts4 ,mo/ ( ! muck f ! top 0 caught on ! plat=m & dropp$ into c>s bel[4 ,?is me?od ( work+ is %[n by ,fig4 #b1 ,plate ,,lxvii4 ,! plat=ms 7 n entirely satisfactory1 &1 lat]1 ! drills 9 ! head+ 7 turn$ upw>d & a top b5* 0 also drill$ & fir$1 z %[n by ,fig4 #c1 ,plate ,,lxvii4 ,!re 0 !n s little excavation left 9 ! top t ! muck 0 all[$ to fall on ! tracks & 0 quickly cle>$ away4 ,! me?od j outl9$ is call$ ! c5t]-head+ me?od1 & 0 ! mo/ satisfactory plan devis$ = full-rock sections4 ,excavation 9 ,"p ,rock & ,"p ,e>?4--,?is 0 probably ! mo/ difficult "w enc\nt]$1 p>ticul>ly :5 ! rock 0 cov]$ ) b\ld]s & co>se %>p s& :i* p]mitt$ a free escape ( air4 ,x 0 necess>y1 be=e remov+ ! rock imm$iately "u ! s(t gr\nd1 to excavate ! e>? 9 advance ( ! %ield to a po9t beyond :]e ! rock 0 to be di/urb$1 & to support1 9 "s way1 ! ro(1 sides1 & face ( ! op5+ ?us made4 ,! hoods 7 design$ ma9ly = ! purpose ( support+ ! ro( & ! sides4 ,) ! fix$ hood x 0 necess>y ei!r to excavate = ! di/ance ( ! desir$ %ove 9 front ( x or else to =ce ! hood into ! undi/urb$ mat]ial4 ,to avoid ?is difficulty1 ! slid+ hoods 7 tri$ z an exp]im5t4 ,9 us+ ! slid+ hood1 :i* w be describ$ 9 detail 9 ,mr4 ,japp's pap]1 ! segm5ts comm5c+ at ! top 7 =c$ =w>d by ! screw rod1 "o at a "t1 z f> z possible into ! undi/urb$ mat]ial4 ,j en\gh mat]ial 0 !n remov$ f und]nea? & 9 front ( ! section to free x1 & x 0 aga9 =c$ =w>d4 ,^! op]ations 7 repeat$ until ! section _h be5 ext5d$ f> en\gh = a %ove4 ,z soon z two or ?ree sections _h be5 pu%$ =w>d 9 ?is way1 ! face ne> ! advance end ( ! slid+ hood 0 protect$ by a brea/ bo>d set on edge & brac$ f ! face4 ,gradually1 all ! segm5ts 7 work$ =w>d1 &1 at ! same "t1 ! :ole s(t gr\nd face 0 %eet$ ) timb]4 ,at times pol+s 7 plac$ ov] ! ext5d$ segm5ts 9 ord] to make room = a second %ove1 z %[n on ,plate ,,lxviii4 ,:5 ! %ield 0 advanc$ ! nuts on ! screw rods 7 loos5$ & ! sections ( ! hoods 7 telescop$ on to ! %ield4 ,! idea 0 +5i\s1 b prov$ impracticable1 because ( ! unequal relative movem5ts ( ! top & bottom ( ! %ield 9 %ov+1 br++ transv]se /ra9s on ! hood sections4 ,illu/ration3 ,,plate ,,lxix ,) ! fix$ hood1 pol+ bo>ds 7 us$ to support ! ro( & sides1 & ! face 0 support$ 9 ! mann] describ$ = ! slid+ hoods4 ,! pol+s 7 usually maple or oak planks1 #b 94 ?ick1 ab\t #h 94 wide1 & #f-a_/b ft4 long4 ,9 advanc+ ! face1 ! top bo>d ( ! old brea/ 0 fir/ remov$1 !n ! mat]ial 0 c>efully work$ out = ! l5g? ( ! pol+4 ,! latt] 0 !n plac$1 ) ! re> end re/+ ov] ! hood & ! =w>d end =c$ z f> z possible into ! undi/urb$ mat]ial4 ,:5 two or ?ree pol+s _h be5 plac$1 a brea/ bo>d 0 set4 ,aft] sev]al pol+s 7 9 position1 _! =w>d ends 7 support$ by "s =m a cantilev] atta*$ to ! hood4 ,plate ,,lxix %[s "o k9d ( supports4 ,9 ?is way all ! s(t mat]ial 0 excavat$ d[n to ! rock surface1 & ! ro(1 sides1 & face 7 %eet$ ) timb]4 ,9 %ov+1 ! pol+s 9 ! ro( & sides 7 lo/4 ,x 0 f\nd t ! brea/ c\ld usually be advanc$ #e ft4 ) safety4 ,! fix$ hood made x possible to set ! face ab\t #g or #h ft4 9 front ( ! cutt+ edge )\t increas+ ! l5g? ( ! pol+s4 ,?is di/ance 0 ample = two %oves1 & 0 g5]ally adopt$1 al?\gh a great _m faces 7 set = "o %ove only4 ,fix$ hoods 7 sub/itut$ = ^? ( ! slid+ type1 orig9ally plac$ on ,%ields ,b & ,d at ,manhattan1 at ab\t ! "t ! latt] enc\nt]$ ! rock at ! reef4 ,9 plac+ ! pol+s & brea/+1 all voids beh9d !m 7 fill$ z f> z possible ) m>% hay or bags ( sawdu/ or clay4 ,to prev5t loss ( air 9 op5 mat]ial1 ! jo9ts betwe5 ! bo>ds 7 pla/]$ ) clay especially prep>$ = ! purpose 9 a pug mill4 ,! slid+ ext5sions to ! floors ( ! work+ comp>tm5ts 7 (t5 us$1 9 ! e>ly "p ( ! "w1 to support ! timb] face or loose rock1 z %[n 9 ,fig4 #a1 ,plate ,,lxviii4 ,at su* times ! front ( ! ext5sions 0 held tightly aga9/ ! plank+ by ! pressure ( ! floor jacks4 ,:ile %ov+1 ! pressure on ! floor jacks 0 gradually releas$1 all[+ ! floors to slide back into ! %ield & /ill af=d support to ! face4 ,! ext5sions also af=d$ conv5i5t work+ plat=ms4 ,!y 7 subject to sev]e b5d+ /ra9s :ile ! %ield 0 be+ %ov$1 h[ev]1 & ! ca/-iron rams 7 frequ5tly brok5 or jamm$4 ,! ext5sions did n la/ beyond ! edge ( ! l$ge at ,manhattan1 nor m ?an ab\t half ?r\gh ! rock "w at ,long ,isl& ,city4 ,! fix$ ext5sions orig9ally plac$ on ,%ields ,a & ,c at ,manhattan 7 n sub/antial en\gh1 & la/$ only a few days4 ,:]ev] ! rock face 0 suffici5tly s\nd & high1 a bottom head+ 0 driv5 "s #bj or #cj ft4 9 advance ( ! %ield4 ,! head+ 0 driv5 & ! cradle plac$ indep5d5tly ( ! face ( ! s(t gr\nd above1 & 9 ! mann] describ$ = all-rock sections4 ,! rema9d] ( ! rock face 0 remov$ by fir+ top & side r\nds into ! bottom head+ aft] ! s(t gr\nd _h be5 excavat$4 ,great c>e _h to be tak5 9 fir+ 9 ord] n to di/urb ! timb] "w or break ! rock away f "u ! brea/ bo>ds4 ,if ei!r occurr$1 a s]i\s run 0 likely to foll[4 ,! bottom-head+ me?od is %[n by ,figs4 #a1 #b1 & #c1 ,plate ,,lxviii1 & ! brea/+ & pol+ by ,fig4 #b1 ,plate ,,lxx4 ,9 ! e>ly "p ( ! "w1 :]e a bottom head+ 0 impracticable1 ! s(t gr\nd 0 fir/ excavat$ z describ$ above1 & ! rock 0 drill$ by ma*9es m\nt$ on tripods1 & fir$ z a b5*4 ,by ?is plan no drill+ c\ld be done until ! s(t gr\nd 0 remov$4 ,?is is call$ ! rock-b5* me?od4 ,lat] ! rock-cut me?od 0 devis$4 ,drills 7 set up on columns 9 ! bottom comp>tm5ts ( ! %ield1 & ! face 0 drill$ :ile "w 0 9 progress on ! s(t gr\nd above4 ,! drill+ 0 done ei!r = a horizontal or v]tical cut & side & top r\nds4 ,! drill]s 7 protect$ :ile at "w by plat=ms ( timb] built out f ! floors ( ! comp>tm5ts above4 ,?is plan1 :ile probably n q z economical ( explosives1 sav$ ne>ly all ! delay due to drill+ ! b5*4 ,illu/ration3 ,,plate ,,lxx1 ,,fig4 #a4--,,small ,,%aft ,,sunk ,,to ,,rock4 ,illu/ration3 ,,plate ,,lxx1 ,,fig4 #b4--;,,brea/+ ,,& ,,pol+ ,,9 ,,front ,,( ,,%ield4 ,illu/ration3 ,,plate ,,lxx1 ,,fig4 #c4--,,%utt]s ,,on ,,front ,,( ,,%ield4 ,illu/ration3 ,,plate ,,lxx1 ,,fig4 #d4--;,,hydraulic ,,erector ,,plac+ ,,segm5t4 ,all-,e>? ,section4--,z describ$ by ,messrs4 ,hay & ,fitzmaurice1 9 a pap] on ! ,blackwall ,tunnel1,c ! contractor _h us$1 ) m>k$ success1 %utt]s 9 ! face ( ! %ield = excavat+ 9 loose op5 mat]ial4 ,he naturally adopt$ ! me?od = ! ,ea/ ,riv] "w4 ,:5 ! %ields 9 ,tunnels ,b & ,d1 at ,manhattan1 ! fir/ to be driv5 ?r\gh s(t gr\nd1 rea*$ a po9t "u ! actual bulkhead l9e1 "w 0 p>tly susp5d$ & %utt]s 7 put 9 place 9 ! face ( ! top & c5t] comp>tm5ts4 ,! %utt]s 9 ! c5t] comp>tm5ts 9 ,%ield ,d are %[n 9 ,fig4 #c1 ,plate ,,lxx1 :ile ! me?od ( "w ) ! %utt]s is %[n by ,figs4 #d1 #e1 #f1 & #g1 ,plate ,,lxviii4 ,fig4 #d on t plate %[s ! %ield ready = a %ove4 ,z ! pressure 0 appli$ to ! %ield jacks1 m5 loos5$ ! nuts on ! screws hold+ ! ends ( ! %utt]s1 & all[$ ! latt] to slide back into ! work+ comp>tm5ts4 ,at ! end ( ! %ove1 ! %utt]s 7 9 ! position %[n 9 ,fig4 #e1 ,plate ,,lxviii4 ,9 prep>+ = a new %ove1 ! slides 9 ! %utt]s 7 op5$1 & ! mat]ial 9 front 0 rak$ into ! %ield4 ,at ! same "t1 ! %utt]s 7 gradually work$ =w>d4 ,! two upp] %utt]s 9 a comp>tm5t 7 g5]ally advanc$ f #ab to #ae 941 aft] :i* ! muck c\ld be %ovel$ out ov] ! bottom %utt]s1 z %[n on ,fig4 #f1 ,plate ,,lxviii1 & ,fig4 #c1 ,plate ,,lxx4 ,no %utt]s 7 plac$ 9 ! bottom comp>tm5ts1 & z ! air pressure 0 n g5]ally high en\gh to keep ! face dry at ! bottom1 ^! comp>tm5ts 7 pretty well fill$ ) ! s(t1 wet quicks&4 ,j be=e %ov+1 ?is mat]ial 0 excavat$ to a po9t :]e x ran 9 fa/] ?an x c\ld be tak5 out4 ,mu* ( ! excavation 9 ! bottom comp>tm5t 0 done by ! bl[-pipe4 ,dur+ ! %ove ! mat]ial f ! bottom comp>tm5t (t5 ran back ?r\gh ! op5 door 9 ! transv]se bulkhead1 z %[n by ,fig4 #e1 ,plate ,,lxviii4 ,9 ! ,blackwall ,tunnel ! mat]ial 0 report$ to h be5 loose en\gh to keep 9 close contact ) ! %utt]s at all times4 ,9 ! ,ea/ ,riv] ,tunnels ?is 0 n ! case4 ,! s& at ! top 0 dry & w\ld (t5 /& ) a v]tical face = "s h\rs4 ,9 advanc+ ! %utt]s1 x 0 difficult to br+ !m into close contact ) ! face at ! end ( ! op]ation4 ,! s(t mat]ial at ! bottom 0 con/antly runn+ into ! l[] comp>tm5t & und]m9+ ! /iff dry mat]ial at ! top4 ,! latt] gradually broke away1 &1 at times1 ! actual face 0 "s feet 9 advance ( ! %utt]s4 ,"u ^? circum/ances1 ! air escap$ freely ?r\gh ! unprotect$ s& face4 ,! jo9ts ( ! %utt]s 7 pla/]$ ) clay1 b ?is did n keep ! air f pass+ out ?r\gh ! l[] comp>tm5ts4 ,?is condition facilitat$ ! =mation ( bl[s1 :i* 7 ( con/ant occurr5ce :]e %utt]s 7 us$ 9 ! s&4 ,9 ,tunnels ,b & ,d1 at ,manhattan1 ! %utt]s 7 us$ 9 ! above mann] cle> across to ! reef4 ,9 ,tunnel ,c1 :i* 0 consid]ably beh9d ,tunnels ,b & ,d1 ! %utt]s1 al?\gh plac$1 7 nev] us$ aga9/ ! face1 & ! excavation 0 c>ri$ on by pol+ ! top & brea/+ ! face4 ,! *ange result$ 9 mu* bett] progress & few] bl[s4 ,! excavation ?r\gh ! s(t mat]ial 9 ,tunnel ,c _h j be5 complet$ :5 ,tunnel ,a 0 />t$1 & ! gangs ( workm5 7 ex*ang$4 ,! "w 9 s(t gr\nd 9 ,tunnel ,a ?us ga9$ ! b5efit ( ! exp]i5ce 9 ,tunnel ,c4 ,%utt]s 7 plac$ only 9 ! top comp>tm5ts 9 ?is tunnel1 &1 z 9 ,tunnel ,c1 7 nev] us$ 9 contact ) ! face4 ,! me?od ( "w is %[n by ,figs4 #a1 #b1 & #c1 ,plate ,,lxxi4 ,! result 0 /ill m rapid progress 9 ,tunnel ,a1 & al?\gh ! loss ( air 0 fully z great 9 ?is tunnel z 9 ! o!r ?ree1 !re 0 only "o bl[ :i* caus$ any consid]able loss ( pressure4 ,9 ,tunnels ,a & ,c ! diaphragms 9 ! re> ( ! c5t] comp>tm5ts ( ! l[] ti]s ( work+ *amb]s 7 remov$ be=e ! %ields ent]$ ! s(t gr\nd4 ,! *ange 0 n ( z mu* advantage 9 s(t gr\nd z 9 rock1 b x facilitat$ ! removal ( ! s(t wet s& 9 ! bottom4 ,9 ,tunnel ,a1 aft] enc\nt]+ gravel1 a belt conveyor 0 susp5d$ f ! travel+ /age ) "o end project+ ?r\gh ! op5+ into ! work+ comp>tm5t4 ,! use ( ! conveyor made x possible to cont9ue muck+ at ! face :ile ! bottom plates ( ! iron l9+ 7 be+ put 9 place1 & result$ 9 a mat]ial increase 9 ! rate ( progress4 ,illu/ration3 ,,plate ,,lxxi ,! %utt]s 7 n plac$ on ! ,long ,isl& %ields at all4 ,j be=e ! %ields pass$ into all s(t gr\nd1 a fix$ hood 0 atta*$ to ea*4 ,! me?od ( work+ 9 s(t gr\nd f ,long ,isl& ,city is illu/rat$ by ,plate ,,lxxii4 ,! full l9es at ! face ( ! %ield %[ ! position ( ! e>? be=e a %ove ( ! %ield1 & ! dott$ l9es %[ ! same aft] ! %ove4 ,! face 0 m9$ out to ! front ( ! hood & brea/$ d[n to a little bel[ ! floor ( ! top pockets ( ! %ield4 ,9 ! middle pocket ! e>? 0 all[$ to take its natural slope back on ! floor4 ,t[>d ! re> ( ! bottom pockets x 0 held by /op-planks4 ,! air pressure 0 always ab\t equal to ! hydro/atic head at ! middle ( ! %ield1 s t ! face 9 ! upp] & middle pockets 0 dry4 ,9 ! l[] pockets x 0 wet1 & fl[$ "u ! pressure ( %ov+ ! %ield4 ,by ?is me?od #d1aie l94 ft4 ( tunnel 0 excavat$ by ! f\r ,long ,isl& %ields 9 #abj days1 f ,novemb] #a/1 #aijg1 to ,m>* #a/1 #aijh4 ,?is 0 an av]age ( #h4gd ft4 p] day p] %ield4 ,! rate ( progress1 ! nature ( ! mat]ials1 & ! me?ods adopt$ are %[n 9 ,table #b4 ,prep>ations = ,junction ( ,%ields4--,z previ\sly m5tion$1 ! ,manhattan %ields 7 /opp$ at ! edge ( ! reef4 ,be=e mak+ ! f9al %ove ( ^? %ields1 special pol+s 7 plac$ ) unusual c>e4 ,! excavation 0 bell-%ap$ to receive ! ,long ,isl& %ields4 ,! arrangem5t ( ! pol+s is %[n by ,figs4 #d & #e1 ,plate ,,lxxi4 ,aft] ! %ields 7 %ov$ into f9al position1 z %[n at ! "r 9 ,fig4 #e1 ! re> end ( ! pol+s re/$ ov] ! cutt+ edge & all[$ room = ! removal ( ! hood4 ,aft] ! latt] _h be5 accompli%$1 ! tempor>y bulkheads ( concrete & clay bags 7 built z a precaution aga9/ bl[s :5 ! %ields 7 close toge!r4 ,an #h-;94 pipe 0 !n driv5 =w>d ?r\gh ! bulkhead = di/ances v>y+ f #cj to #ajj ft41 9 ord] to *eck ! alignm5t & grade betwe5 ! two work+s be=e ! %ields 7 actually %ov$ toge!r4 ,! errors 9 ! surveys 7 negligible1 b "h1 z else:]e1 ! %ields 7 n exactly 9 ! desir$ position1 & x took c>eful h&l+ to br+ ! cutt+ edges toge!r4 ,! ,long ,isl& %ields 7 driv5 to meet ^? f ,manhattan4 ,,table #b4--,,rate ,,( ,,progress1 ,,nature ,,( ,,mat]ials1 ,,& ,,me?ods ,,adopt$ ,,9 ,,con/ruction ,,( ,,ea/ ,,riv] ,,tunnels4 ,,l9e ,a1 ,,long ,,isl&4 ---------------------------------------- ----------------------------------- ,/ation3 ,date3 ---------------------------------------- -- ,mat]ial4 ,me?od4 ,f ,to ,f ,to ---------------------------------------- --------------------------------- ,all rock ,bottom head+ #fici4i #figi ,aug4 #b1 '#jf,sept #be1 '#jf ,all rock ,c5t] head+ #figi #gjfd ,sept #be1 '#jf,nov4 #ba1 '#jf ,e>? & rock,c5t] head+ #gjfd #gacd ,nov4 #ba1 '#jf;,dec4 #cj1 '#jf ,e>? & rock,bottom head+ #gacd #gahi ,dec4 #cj1 '#jf;,feb4 #ac1 '#jg ,all rock ,bottom head+ #gahi #gbaa ,feb4 #ac1 '#jg;,feb4 #ba1 '#jg ,e>? & rock,c5t] head+ #gbaa #gbfg ,feb4 #ba1 '#jg,m>4 #ai1 '#jg ,all rock ,c5t] head+ #gbfg #gfed ,m>4 #ai1 '#jg,sept #f1 '#jg ,e>? & rock,go+ out ( rock #gfed #ggbd ,sept #f1 '#jg,oct4 #d1 '#jg ,all e>? ,s(t gr\nd #ggbd #ijeg4c ,oct4 #d1 '#jg,m>4 #bf1 '#jh ---------------------------------------- --------------------------------- ---------------------------------------- ---------------------------------- ,rate ( ,numb] progress ( ,l9e> 9 feet ,mat]ial4 days4 feet4 p] day4 ,rem>ks ---------------------------------------- ---------------------------------- ,all rock #ed #ci4a #j4gbd ,all rock #eg #he #a4di ,e>? & rock #ci #gj #a4gi ,e>? & rock #de #ee #a4bb ,all rock #h #bb #b4ge ,e>? & rock #bf #ef #b4ae ,all rock #aga #chg #b4bf ,e>? & rock #bh #gj #b4ej ,all e>? #agd #a1ccc4c #g4ff ---------------------------------------- ---------------------------------- ,,l9e ,b1 ,,long ,,isl&4 ---------------------------------------- ----------------------------------- ,/ation3 ,date3 ---------------------------------------- -- ,mat]ial4 ,me?od4 ,f ,to ,f ,to ---------------------------------------- --------------------------------- ,all rock ,bottom head+ #fibi4f #gjdf ,oct4 #af1 '#jf,nov4 #bj1 '#jf ,e>? & rock,bottom head+ #gjdf #gaie ,nov4 #bj1 '#jf;,feb4 #bc1 '#jg ,all rock ,bottom head+ #gaie #gbbe ,feb4 #bc1 '#jg,m>4 #f1 '#jg ,e>? & rock,c5t] head+ #gbbe #gbfj ,m>4 #f1 '#jg,m>4 #bd1 '#jg ,all rock ,go+ out ( rock #gbfj #gfeg ,m>4 #bd1 '#jg;,aug4 #g1 '#jg ,e>? & rock,s(t gr\nd #gfeg #ggcj ,aug4 #g1 '#jg,sept #e1 '#jg ,all e>? ,s(t gr\nd #ggcj #ijdi4f ,sept #e1 '#jg,m>4 #ai1 '#jh ---------------------------------------- --------------------------------- ---------------------------------------- ---------------------------------- ,rate ( ,numb] progress ( ,l9e> 9 feet ,mat]ial4 days4 feet4 p] day4 ,rem>ks ---------------------------------------- ---------------------------------- ,all rock #ce #aaf4d #c4cc ,e>? & rock #ie #adi #a4eg ,all rock #aa #cj #b4gc ,e>? & rock #ah #ce #a4id ,all rock #acf #cig #b4ib ,e>? & rock #bi #gc #b4eb ,all e>? #aif #a1cai4f #f4gc ---------------------------------------- ---------------------------------- ,,l9e ,c1 ,,long ,,isl&4 ---------------------------------------- ----------------------------------- ,/ation3 ,date3 ---------------------------------------- -- ,mat]ial4 ,me?od4 ,f ,to ,f ,to ---------------------------------------- --------------------------------- ,all rock ,bottom head+ #fhfa4i #fiic ,june #aa1 '#jf,oct4 #af1 '#jf ,e>? & rock,bottom head+ #fiic #gafe ,oct4 #af1 '#jf;,feb4 #g1 '#jg ,all rock ,bottom head+ #gafe #gaia ,feb4 #g1 '#jg;,feb4 #ac1 '#jg ,all rock ,c5t] head+ #gaia #geha ,feb4 #ac1 '#jg;,july #bj1 '#jg ,e>? & rock,go+ out ( rock #geha #gfef ,july #bj1 '#jg;,aug4 #be1 '#jg ,all e>? ,s(t gr\nd #gfef #ijdd4d ,aug4 #be1 '#jg,m>4 #ag1 '#jh ---------------------------------------- --------------------------------- ---------------------------------------- ---------------------------------- ,rate ( ,numb] progress ( ,l9e> 9 feet ,mat]ial4 days4 feet4 p] day4 ,rem>ks ---------------------------------------- ---------------------------------- ,all rock #abg #aca4a #a4jc ,e>? & rock #aad #agb #a4ea ,all rock #f #bf #d4cc ,all rock #aeg #cij #b4dh ,e>? & rock #cf #ge #b4jh ,all e>? #bje #a1chh4d #f4gg ---------------------------------------- ---------------------------------- ,,l9e ,d1 ,,long ,,isl&4 ---------------------------------------- ----------------------------------- ,/ation3 ,date3 ---------------------------------------- -- ,mat]ial4 ,me?od4 ,f ,to ,f ,to ---------------------------------------- --------------------------------- ,rock ,bottom head+ #fhej4f #figg ,june #b1 '#jf,oct4 #bd1 '#jf ,e>? & rock,bottom head+ #figg #gabb ,oct4 #bd1 '#jf;,jan4 #ac1 '#jf ,all rock ,bottom head+ #gabc #gbjj ,jan4 #ac1 '#jg,m>4 #c1 '#jg ,all rock ,c5t] head+ #gbjj #gegc ,m>4 #c1 '#jg;,july #aj1 '#jg ,e>? & rock,go+ out ( rock #gegc #ggfc ,july #aj1 '#jg,sept #be1 '#jg ,all e>? ,s(t gr\nd #ggfc #ijch4f ,sept #be1 '#jg,m>4 #g4 '#jh ---------------------------------------- --------------------------------- ---------------------------------------- ---------------------------------- ,rate ( ,numb] progress ( ,l9e> 9 feet ,mat]ial4 days4 feet4 p] day4 ,rem>ks ---------------------------------------- ---------------------------------- ,rock #add #abf4d #j4hg ,e>? & rock #ha #ade #a4gi ,all rock #di #gh #a4ei ,all rock #abi #cgc #b4hi ,e>? & rock #gg #aij #b4dg ,all e>? #afd #a1bge4f #g4gh ---------------------------------------- ---------------------------------- ,,l9e ,a1 ,,manhattan4 ---------------------------------------- ----------------------------------- ,/ation3 ,date3 ---------------------------------------- -- ,mat]ial4 ,me?od4 ,f ,to ,f ,to ---------------------------------------- --------------------------------- ,top head+ #ajhdc #ajggd ,july #bj1 '#je;,aug4 #c1 '#je ,rock ,top lift ( b5*#ajhdc #ajggd ,aug4 #h1 '#je;,aug4 #bc1 '#je ,bottom lift ( #ajhdc #ajggd ,aug4 #cj1 '#je,sept #bg1 '#je b5* ,rock ,bottom head+ #ajggd #ajgba ,sept #bg1 '#je,oct4 #bc1 '#je ,bottom head+ #ajggd #ajgba ,nov4 #cj1 '#je;,dec4 #bi1 '#je ,mix$ ,bottom head+ #ajgba #ajfii ,oct4 #bf1 '#jf,nov4 #bj1 '#jf ,mix$ ,rock b5* #ajfii #ajfcd ,nov4 #bj1 '#jf;,jan4 #ac1 '#jg ,e>? ,pol+ & #ajfcd #iiaa ,jan4 #ac1 '#jg;,apr4 #ag1 '#jg brea/+ ,mix$ ,rock cut #iiaa #icif ,apr4 #ag1 '#jg,oct4 #bd1 '#jg ,rock ,bottom head+ #icif #iceh ,oct4 #bd1 '#jg,nov4 #ad1 '#jg ,rock ,c5t] head+ #iceh #ibdb ,nov4 #ad1 '#jg;,dec4 #bg1 '#jg ,rock ,bottom head+ #ibdb #iaje ,dec4 #bg1 '#jg;,feb4 #bd1 '#jh ,mix$ ,rock cut #iaje #ijeg ,feb4 #bd1 '#jh,m>4 #bj1 '#jh ---------------------------------------- --------------------------------- ---------------------------------------- ---------------------------------- ,rate ( ,numb] progress ( ,l9e> 9 feet ,mat]ial4 days4 feet4 p] day4 ,rem>ks ---------------------------------------- ---------------------------------- #ad ,excavation 9 normal air1 & be=e ,rock #aeeg #fi #a4ba advance ( %ield4 #bh ,rock #bfee #ec #j4if ,bottom head+ timb]$ to avoid ! #bi possibility ( a break4 ,mix$ #be #bb #j4hh ,bottom head+ timb]$4 ,mix$ #ed #fe #a4bj ,e>? #id #gbc #g4fi ,mix$ #aij #eae #b4ga ,rock #ba #ch #a4ha ,rock #df #aaf #b4eb ,rock #ei #acg #b4cb ,mix$ #be #dh #a4ib ---------------------------------------- ---------------------------------- ,,l9e ,b1 ,,manhattan4 ---------------------------------------- ----------------------------------- ,/ation3 ,date3 ---------------------------------------- -- ,mat]ial4 ,me?od4 ,f ,to ,f ,to ---------------------------------------- --------------------------------- ,top head+ #ajhce #ajghg ,july #f1 '#je;,july #bg1 '#je ,top lift ( b5*#ajhce #ajghg ,aug4 #c1 '#je;,aug4 #ad1 '#je ,rock ,bottom lift ( b5* #ajhce #ajhae ,aug4 #bf1 '#je;,aug4 #cj1 '#je ,bottom lift ( b5* #ajhae #ajghg ,sept #aa1 '#je,sept #bf1 '#je ,rock ,bottom head+ #ajghg #ajgjj ,oct4 #bc1 '#je;,jan4 #ag1 '#jf ,mix$ ,bottom head+ #ajgjj #ajffd ,jan4 #ag1 '#jf;,feb4 #ab1 '#jf ,mix$ ,rock b5* #ajffd #ajfca ,feb4 #ab1 '#jf,m>4 #a1 '#jf ,e>? ,pol+ & #ajfca #ajeeh ,m>4 #a1 '#jf;,apr4 #c1 '#jf brea/+ ,%utt]s 9 ,e>? contact ) #ajeeh #iiai ,apr4 #i1 '#jf,nov4 #a1 '#jf face ,mix$ ,rock b5* #iiai #ihdd ,nov4 #a4 '#jf;,dec4 #bi1 '#jf ,mix$ ,bottom head+ #ihdd #iggf ,dec1 #bi1 '#jf;,feb4 #ab1 '#jg ,mix$ ,rock cut #igff #ichd ,feb4 #ab1 '#jg;,aug4 #f1 '#jg ,rock ,full face #ichd #icba ,aug4 #f1 '#jg,sept #b1 '#jg ,rock ,c5t] ,head+ #icba #ibcj ,sept #b1 '#jg,oct4 #ab1 '#jg ,rock ,bottom head+ #ibcj #ijii ,oct4 #ab1 '#jg;,dec4 #f1 '#jg ,mix$ ,rock cut #ijii #ijdi4f ,dec4 #f1 '#jg;,jan4 #c1 '#jh ---------------------------------------- --------------------------------- ---------------------------------------- ---------------------------------- ,rate ( ,numb] progress ( ,l9e> 9 feet ,mat]ial4 days4 feet4 p] day4 ,rem>ks ---------------------------------------- ---------------------------------- #ba #aa ,rock #ea #dh #j4id ,excavation done 9 normal air & #d be=e advance ( %ield4 #ae ,rock #hf #hg #a4ja ,mix$ #bf #cf #a4ch ,mix$ #ag #cc #a4id ,e>? #cc #gc #b4ba ,e>? #bjf #fci #c4aj ,mix$ #eh #ge #a4cj ,mix$ #de #fh #a4ea ,mix$ #age #cib #b4bd ,rock #bg #fc #b4cc ,rock #dj #ia #b4bh ,rock #ee #aca #b4ch ,mix$ #bh #di4d #a4gf ---------------------------------------- ---------------------------------- ,,l9e ,c1 ,,manhattan4 ---------------------------------------- ----------------------------------- ,/ation3 ,date3 ---------------------------------------- -- ,mat]ial4 ,me?od4 ,f ,to ,f ,to ---------------------------------------- --------------------------------- ,top head+ #ajggi4jcajgfi ,dec4 #bj1 '#jd;,dec4 #bg1 '#jd ,top head+ #ajgfi #ajgbc ,jan4 #a1 '#je;,jan4 #ae1 '#je ,rock ,excavat+ b5* #ajggi #ajgbc ,jan4 #ba1 '#je;,feb4 #bh1 '#je ,bottom head+ #ajgbc #ajfgb ,m>4 #a1 '#je,m>4 #aa1 '#je ,bottom head+ #ajgbc #ajgae ,oct4 #ab1 '#je,oct4 #bg1 '#je ,rock ,bottom head+ #ajgae #ajffb ,nov4 #f1 '#je;,dec4 #b1 '#je ,mix$ ,bottom head+ #ajffb #ajfee ,dec4 #b1 '#je;,dec4 #bc1 '#je ,mix$ ,bottom head+ #ajfee #ajfag ,feb4 #ab1 '#jf,m>4 #bb1 '#jf ,mix$ ,rock cut #ajfag #ajehe ,apr4 #b1 '#jf;,apr4 #bj1 '#jf ,mix$ ,rock cut #ajehe #ajeee ,july #bg1 '#jf;,aug4 #bf1 '#jf ,e>? ,brea/+ & #ajeee #iidj ,aug4 #bf1 '#jf;,jan4 #b1 '#jg pol+ ,mix$ ,rock cut #iidj #ihgj ,jan4 #b1 '#jg;,feb4 #f1 '#jg ,rock ,full face #ihgj #ihfj ,feb4 #f1 '#jg;,feb4 #ab1 '#jg ,mix$ ,bottom head+ #ihfj #ihci ,feb4 #ab1 '#jg,m>4 #f1 '#jg ,rock ,bottom head+ #ihci #ihag ,m>4 #f1 '#jg,m>4 #ae1 '#jg ,mix$ ,rock cut #ihag #iefh ,m>4 #ae1 '#jg;,july #cj1 '#jg ,rock ,middle head+ #iefh #idfa ,july #cj1 '#jg;,aug4 #ba1 '#jg ,mix$ ,rock cut #idfa #icef ,aug4 #ba1 '#jg,oct4 #c1 '#jg ,rock ,middle head+ #icef #ibgc ,oct4 #c1 '#jg,nov4 #aa1 '#jg ,mix$ ,rock cut #ibgc #ijee ,nov4 #aa1 '#jg;,feb4 #ac1 '#jh ,mix$ ,rock cut #ijee #ijdd4d ,feb4 #be1 '#jh,m>4 #c1 '#jh ---------------------------------------- --------------------------------- ---------------------------------------- ---------------------------------- ,rate ( ,numb] progress ( ,l9e> 9 feet ,mat]ial4 days4 feet4 p] day4 ,rem>ks ---------------------------------------- ---------------------------------- #g ,/opp$ to brace portal4 ,no "w done #ad f ,m>* #ab? to ,octob] #aa?1 #aije1 ,rock #ch #ed #j4gg except a little trimm+ 9 ,septemb]4 #aj ,all "w up to ?is date done 9 #ae normal air4 ,head+ advanc$ to #ajfgj & bulkhead$4 ,rock #bf #ec #b4jd ,head+ advanc$ to #ajf #dj4 ,%ut ,mix$ #ba #g #j4cc d[n 9 ord] t ,l9e ,d might h a lead4 ,mix$ #ch #ch #a4jj ,%ut d[n on acc\nt ( air %ortage4 ,mix$ #ah #cb #a4gh ,%ut d[n on acc\nt ( air %ortage4 ,mix$ #cj #cj #a4jj ,%ut d[n ,april #bj? to ,july #bg?1 #aijf4 ,e>? #abg #fae #d4hd ,mix$ #ce #gj #b4jj ,rock #f #aj #a4ff ,mix$ #bb #ba #j4ie ,rock #i #bb #b4dd ,mix$ #aaj #bdi #b4bf ,head+ advanc$ to #ighb4 ,rock #di #ajg #b4ah #idce4 ,mix$ #dc #ajf #b4df ,rock #ci #hc #b4ac ,mix$ #id #bah #b4cb ,%ut d[n until ,l9e ,d %ields met4 ,mix$ #f #aa #a4hc ---------------------------------------- ---------------------------------- ,,l9e ,d1 ,,manhattan4 ---------------------------------------- --------------------------------- ,top head+ #ajggj4diajgaf ,dec4 #i1 '#jd;,jan4 #ca1 '#je ,remov+ b5* #ajggj4diajgce ,jan4 #a1 '#je;,jan4 #bg1 '#je ,rock ,bottom head+ #ajgce #ajfhj ,jan4 #cj1 '#je;,feb4 #aj1 '#je ,trimm+ #ajggj #ajfhj ,m>4 #bi1 '#je;,apr4 #ab1 '#je ,trimm+ #ajggj #ajfhj ,aug4 #ca1 '#je,sept #ai1 '#je ,rock ,bottom head+ #ajfhj #ajffg ,oct4 #e1 '#je,nov4 #h1 '#je ,mix$ ,bottom head+ #ajffg #ajfci ,nov4 #h1 '#je;,dec4 #bc1 '#je ,slid+ hood & ,mix$ brea/+4 ,rock #ajfbi #ajegj ,dec4 #bc1 '#je;,jan4 #bd1 '#jf b5* ,e>? ,pol+ & #ajegj #ajdfa ,jan4 #bd1 '#jf;,feb4 #bg1 '#jf brea/+ ,e>? ,pol+1 brea/+#ajdfa #ajcij ,m>4 #b1 '#jf,m>4 #ca1 '#jf & %utt]s ,e>? ,%utt]s #ajcij #iida ,apr4 #bj1 '#jf,sept #c1 '#jf ,mix$ ,bottom b5* #iida #iiag ,sept #c1 '#jf,sept #bc1 '#jf ,mix$ ,bottom head+ #iiag #ihej ,oct4 #b1 '#jf,nov4 #bd1 '#jf ,rock ,bottom head+ #ihej #iggb ,nov4 #bd1 '#jf;,jan4 #af1 '#jg ,mix$ ,bottom head+ #iggb #igbg ,jan4 #af1 '#jg;,feb4 #aj1 '#jg ,mix$ ,rock cut #igbg #iegb ,feb4 #aj1 '#jg;,apr4 #bc1 '#jg ,rock ,middle head+ #iegb #ieeg ,apr4 #bc1 '#jg,may #aa1 '#jg ,rock ,middle head+ #ieeg #idfe ,may #bc1 '#jg;,june #ag1 '#jg ,mix$ ,middle head+ #idfe #idda ,june #ag1 '#jg;,june #be1 '#jg ,mix$ ,rock cut #idda #idjc ,june #be1 '#jg;,july #ac1 '#jg ,rock ,middle head+ #idjc #ibfd ,july #ac1 '#jg,sept #ab1 '#jg ,mix$ ,middle head+ #ibfd #ibed ,sept #ab1 '#jg,sept #bj1 '#jg ,rock ,middle head+ #ibed #ibej ,sept #bj1 '#jg,sept #ba1 '#jg ,mix$ ,rock cut #ibej #ijch4ff,sept #ba1 '#jg;,jan4 #h1 '#jh ---------------------------------------- --------------------------------- ---------------------------------------- ---------------------------------- ,rate ( ,numb] progress ( ,l9e> 9 feet ,mat]ial4 days4 feet4 p] day4 ,rem>ks ---------------------------------------- ---------------------------------- ,rock #abc #ij #j4gc ,9 normal air4 ,rock #cd #ac #j4dj ,bottom head+ timb]$4 ,mix$ #de #ch #j4hd ,mix$ #cb #ei #a4hd ,e>? #ca #aji #c4da ,?ree days' delay to set %utt]s 9 ,e>? #bi #ga #b4de top4 ,%ut d[n #bj days to p]mit consolidation ( ! riv] b$ & to repair brok5 plates4 ,e>? #acf #ddi #c4dj ,f\r days ( #acf1 delay acc\nt ( flood4 ,mix$ #bj #bd #a4bj ,mix$ #ec #fg #a4bg ,?irte5 days' %ut-d[n to put on hood4 ,rock #ec #gh #a4dg ,mix$ #be #de #a4dj ,mix$ #gb #aee #b4ae ,rock #ah #ae #j4hc ,rock #be #ib #c4fh ,twelve days' delay to repair cutt+ edge4 ,mix$ #h #bd #c4jj ,mix$ #ah #ch #b4aa ,rock #fa #aci #b4bh ,mix$ #h #aj #a4be ,rock #a #d #d4jj ,mix$ #aji #baa4cd #a4id ---------------------------------------- ---------------------------------- ,op5+s 7 made betwe5 ! head+s z foll[s3 ,tunnel ,d1 ,febru>y #bj?1 #aijh2 ,tunnel ,b1 ,m>* #c;d1 #aijh2 ,tunnel ,c1 ,m>* #e?1 #aijh2 ,tunnel ,a1 ,m>* #ah?1 #aijh4 ,x 0 necess>y to cut away ! project+ floors ( ! work+ comp>tm5ts be=e ! cutt+ edges c\ld be %ov$ toge!r4 ,contractor's ,organization4--,tunnel op]ations 7 c>ri$ on cont9u\sly = ?irte5 days out ( f\rte51 regul> "w be+ %ut d[n = repairs on alt]nate ,sundays4 ,:5 ! requir$ pressure 0 m ?an #cb lb41 f\r gangs ( labor]s 7 employ$1 ea* gang work+ two %ifts ( #c h\rs ea*1 ) an int]mission ( #c h\rs betwe5 ! %ifts4 ,:5 ! pressure 0 less ?an #cb lb41 ?ree gangs 7 employ$1 ea* gang cov]+ #h h\rs1 b ) an int]mission ( ab\t #a_/b h\r 9 l[ pressure = lun*4 ,air ,pressures ,requir$4--,dur+ ! great] portion ( ! "w 9 s(t gr\nd1 pressure 0 ma9ta9$ :i* w\ld ab\t balance ! hydro/atic head at ! axis ( ! tunnel4 ,?is requir$ a pressure v>y+ f #cj to #cd lb4 p] sq4 94 above t ( ! atmosph]e4 ,9 ,tunnels ,b & ,d1 at ,manhattan1 dur+ ! "w 9 s(t gr\nd1 pressures z high z #cg lb4 7 ma9ta9$ = consid]able p]iods ( "t2 9 ! firm mat]ial ne> ! reef #bh lb4 0 (t5 suffici5t4 ,:ile remov+ ! brok5 plates1 ! pressure 0 rais$ = a %ort "t to #db lb41 & 0 ma9ta9$ betwe5 #cg-a_/b & #dj lb4 = a little m ?an "o mon?4 ,air ,supply4--,= regul> op]ation ! contractor furni%$ f\r compressors on ea* side ( ! riv]1 ea* hav+ a rat$ capacity ( #e1jjj cu4 ft4 ( free air p] m9ute deliv]$ at #ej lb4 above normal1 :5 runn+ at ! rate ( #ajj rev4 p] m94 ,an additional compressor ( ! same capacity 0 suppli$ on ea* side ( ! riv]1 9 compliance ) ! requirem5t = #be excess capacity2 ! additional compressors _h also high-pressure air cyl9d]s :i* c\ld be connect$ at w1 & 9 :i* ! pressure c\ld be increas$ to #aej lb41 & ! air us$ to supply rock drills1 gr\t+ ma*9es1 etc4 ,! entire comb9ation on ea* side ( ! riv]1 !re=e1 0 rat$ at #be1jjj cu4 ft4 ( free air p] m9ute1 or a mean ( #f1bej cu4 ft4 p] head+4 ,its safe work+ capacity 0 n f> f #bj1jjj cu4 ft4 p] m94 ,! %ields broke ?r\gh rock surface 9 ,tunnels ,b1 ,c1 & ,d1 at ,manhattan1 9 ,novemb] & ,decemb]1 #aije4 ,! consumption ( air 9 ! f\r tunnels soon exce$$ #ae1jjj cu4 ft4 = #bd h\rs1 & 9 ,tunnel ,d1 on sev]al occasions1 x exce$$ #g1jjj cu4 ft4 = a l p]iod4 ,bl[s _h become frequ5t1 & x 0 evid5t t ! air plant 0 inadequate = driv+ f\r tunnels at once 9 ! op5 mat]ial ea/ ( ! ,manhattan rock4 ,"w 9 ,tunnel ,a1 !re=e1 0 n resum$1 aft] ! susp5sion on ,decemb] #bi?1 = ab\t t5 mon?s1 & ,tunnel ,c 0 also clos$ d[n = m ?an f\r mon?s ( ! "t betwe5 ,decemb]1 #aije1 & ,july1 #aijf4 ,dur+ ?is p]iod ! capacity ( ! plant 0 increas$ f ! rat$ #be1jjj cu4 ft4 ( free air p] m9ute1 to #ce1jjj4 ,9 ,tunnel ,d ! mat]ial _h gradually become firm]1 ) m clay & less escape ( air1 z ! ,blackwell's ,isl& ,reef 0 approa*$1 &1 at ! end ( ! p]iod1 ! rock surface 0 )9 #c ft4 ( ! top ( ! %ield2 9 ,tunnel ,b1 ! rock ( ! reef 0 /ill a little bel[ ! %ield1 b ! ov]ly+ mat]ial conta9$ a l>ge proportion ( clay & held air v well4 ,tunnel ,c 0 /ill 9 op5 mat]ial1 b1 ) two l9es safe & ) ! increas$ air plant1 x 0 deem$ be/ to resume "w 9 ,tunnel ,a1 :i* 0 done on ,octob] #bc;d1 #aijf4 ,!nce=w>d "w 0 cont9u\s 9 all head+s until ! meet+ po9ts ) ! ,long ,isl& %ields 7 rea*$4 ,?is p]iod1 ,janu>y to ,octob]1 #aijf1 inclusive1 0 ! mo/ /r5u\s ( ! entire "w1 p>ticul>ly ! fir/ six mon?s4 ,) "o &1 at times1 two tunnels clos$ d[n1 ! consumption ( air 9 ! head+s f ,manhattan 0 an av]age ( m ?an #bj1jjj cu4 ft4 p] m94 = p]iods ( f #cj to #fj days2 x 0 (t5 m ?an #be1jjj cu4 ft4 = #bd h\rs1 ) a maximum ( ne>ly #bi1jjj cu4 ft41 & d\btless ?is 0 exce$$ consid]ably = %ort] p]iods4 ,on sev]al occasions ! quantity suppli$ to a s+le tunnel av]ag$ m ?an #ae1jjj cu4 ft4 p] m94 = #bd h\rs4 ,! greate/ av]ages = #bd h\rs 7 obta9$ lat] 9 ,tunnel ,a1 aft] ! resumption ( "w !re1 & exce$$ #ai1jjj cu4 ft41 b ! conditions 9 ! head+s ( ! o!r l9es 7 !n s favorable t ! "w 0 c>ri$ on cont9u\sly 9 all4 ,! defici5cy 9 ! orig9al plant at ,manhattan 0 s m>k$1 & ! ne$ ( driv+ all head+s f ,long ,isl& simultane\sly s cle>1 t x 0 decid$ to increase ! rat$ capacity ( ! ,long ,isl& compressor plant to #de1djj cu4 ft4 ( free air p] m9ute1 :i* 0 #aj1djj cu4 ft4 great] ?an ! capacity ( ! ,manhattan plant aft] ! latt] _h be5 augm5t$4 ,illu/ration3 ,,plate ,,lxxii ,! e>? enc\nt]$ on em]g+ f rock1 :5 driv+ we/w>d f ,long ,isl&1 0 f> m compact & less p]meable to air ?an on ! ,manhattan side1 b = a di/ance ( f #djj to #fjj ft4 imm$iately ea/ ( ! reef1 x 0 a clean op5 s&1 &1 :ile ! %ields 7 pass+ ?r\gh ?is1 ! quantity ( air suppli$ to ! f\r head+s seldom fell bel[ #bj1jjj cu4 ft4 p] m942 x 0 usually m ?an #be1jjj cu4 ft41 ) a record$ maximum ( #cc1djj cu4 ft4 ,al?\gh ?is 0 great] ?an ev] us$ on ! ,manhattan side1 x 0 m uni=mly di/ribut$ among ! sev]al head+s1 & 9 none equall$ ! maximum obs]v$ on ! ,manhattan side1 ! l>ge/ hav+ be5 #ab1gjj cu4 ft4 p] m94 = #bd h\rs2 x mu/ be rememb]$1 h[ev]1 t at "o "t only two tunnels 7 9 progress 9 ! bad mat]ial 9 ! tunnels f ,manhattan4 ,f ! =ego+ exp]i5ce1 x w\ld seem t ! plant f9ally furni%$ at ,long ,isl&1 hav+ a rat$ capacity ( #de1djj cu4 ft4 ( free air p] m9ute1 w\ld h be5 a reasonable compliance ) ! orig9al actual ne$s on ! ,manhattan side & vice v]sa2 ! plant f9ally develop$ on ! ,manhattan side1 hav+ a rat$ capacity ( #ce1jjj cu4 ft4 ( free air p] m9ute1 w\ld h suffic$ = ! ,long ,isl& side4 ,! total quantity ( free air compress$ = ! supply ( ! work+ *amb]s ( ! tunnels & ! ,long ,isl& caissons 0 #cd1aji1jjj1jjj cu4 ft41 &1 9 addition1 #aj1fae1jjj1jjj cu4 ft4 7 compress$ to betwe5 #hj & #abe lb4 = p[] purposes1 ( :i* at lea/ #hj 0 exhau/$ 9 ! compress$-air work+ *amb]s4 ,! total supply ( free air to ea* head+ :ile "u pressure1 !re=e1 av]ag$ ab\t #c1eej cu4 ft4 p] m94 ,! quantity ( air escap+ dur+ a sudd5 bl[-out is app>5tly mu* small] ?an might be suppos$4 ,inve/igation ( a numb] ( cases1 %[+ l>ge pressure losses comb9$ ) a long /ret* ( tunnel supply+ a relatively l>ge res]voir ( air1 disclos$ t a maximum loss ( ab\t #bbj1jjj cu4 ft4 ( free air occurr$ 9 #aj m94 ,?is av]ages only a little m ?an #ai1jjj cu4 ft4 p] m941 ! maximum record$ supply to "o tunnel = a p]iod ( #bd h\rs4 ,( ?is quantity1 h[ev]1 probably f #cj to #dj escap$ 9 ! fir/ #de seconds1 :ile ! rema9d] 0 a m or less /eady loss up to ! "t :5 ! supply c\ld be increas$ suffici5tly to ma9ta9 ! l[]$ pressure4 ,v few bl[s %[$ losses approa*+ ?is 9 quantity1 b ! inh]5t inaccuracy ( ! obs]vations make ! =ego+ figures only r\ghly approximate4 ,footnote ,c3 ,m9utes ( ,proce$+s1 ,in/4 ,c4 ,e41 ,vol4 ,,cxxx1 p4 #ej4 ,,special ,,difficulties4 ,! mo/ s]i\s difficulties ( ! "w came ne> ! />t4 ,9 ,tunnel ,d bl[s & falls ( s& f ! face 7 frequ5t aft] s(t gr\nd 0 met 9 ! top4 ,ab\t six weeks aft] ent]+ ! full s& face1 & be=e ! %utt]s _h be5 in/all$1 ! %ield %[$ a decid$ t5d5cy to settle1 c>ry+ ! tunnel l9+ d[n ) x & result+ 9 a numb] ( badly brok5 plates 9 ! bottom ( ! r+s4 ,not)/&+ ! use ( extremely high v]tical leads1,d ! s& 0 s s(t t ! settlem5t ( ! %ield cont9u$ = ab\t fifte5 r+s1 ! maximum be+ ne>ly #i 94 bel[ grade4 ,! hydro/atic head at mid-height ( ! tunnel 0 #cb-a_/b lb41 & ! rais+ ( ! air pressure to #cg lb41 z 0 done at ?is "t1 0 att5d$ ) grave dang] ( s]i\s bl[s1 on acc\nt ( ! rec5t di/urbance ( ! natural cov] by ! pull+ & re-driv+ ( piles 9 ! recon/ruction ( ! ,long ,isl& f]ry slips directly above4 ,x dri$ ! face mat]ially1 h[ev]1 & ! %ield began to rise aga91 & _h practically rega9$ ! grade :5 ! anticipat$ bl[-outs occurr$1 culm9at+ ) ! entrance ( rip-rap f ! riv] b$ into ! %ield & ! flood+ ( ! tunnel ) #d ft4 ( s& & wat] at ! =w>d end4 ,! escape ( air 0 v great1 &1 z a pressure ( m ?an #bh lb4 c\ld n be ma9ta9$1 ! face 0 bulkhead$ & ! tunnel 0 %ut d[n = ?ree weeks 9 ord] to p]mit ! riv] b$ to consolidate4 ,?is 0 ! mo/ s]i\s difficulty enc\nt]$ on any "p ( ! "w1 &1 com+ at ! v />t1 0 exce$+ly disc\rag+4 ,dur+ ! %ut-d[n ! brok5 plates 7 re9=c$ tempor>ily ) /eel ribs & re9=c$ concrete 7,fig4 #a1 ,plate ,,lxxiii7 :i*1 on completion ( ! "w1 7 replac$ by ca/-/eel segm5ts1 z describ$ else:]e4 ,practically1 no fur!r movem5t ( iron took place1 & ! loss ( grade caus$ by ! settlem5t ( ! %ield1 :i* 0 by f> ! l>ge/ t ev] occurr$ 9 ?is "w1 0 n suffici5t to require a *ange 9 ! design$ grade or alignm5t ( ! track4 ,"w 0 resum$ ) ! %utt]s 9 use at ! face z an aid to excavation4 ,! features ( extreme s]i\sness did n recur1 b = two mon?s ! escape ( air cont9u$ to be extremely l>ge1 an av]age ( #ae1jjj cu4 ft4 p] m94 be+ requir$ on _m days dur+ ?is p]iod4 ,illu/ration3 ,,plate ,,lxxiii1 ,,fig4 #a4--,,tempor>y ,,re9=cem5t ,,( ,,brok5 ,,plates ,,& ,,removal ,,( ,a ,,plate ,,9 ,,sections4 ,illu/ration3 ,,plate ,,lxxiii1 ,,fig4 #b4--;,,heavy ,,ca/-,,/eel ,,pat* ,,atta*$ ,,to ,,b5t ,,segm5t ,,( ,,cutt+ ,,edge4 ,illu/ration3 ,,plate ,,lxxiii1 ,,fig4 #c4--;,,infl[ ,,( ,,s(t ,,clay ,,?r\gh ,,%ield4 ,illu/ration3 ,,plate ,,lxxiii1 ,,fig4 #d4--,,re9=cem5t ,,( ,,brok5 ,,plate ,,) ,,long ,,polt ,,& ,,twi/$ ,,/eel ,,rods4 ,9 ,tunnel ,b1 aft] pass+ out f "u ! bulkhead l9e1 9 ,april1 #aijf1 ! loss ( air became v great1 & bl[-outs 7 ( almo/ daily occurr5ce until ! end ( ,june4 ,at ! "t ( ! bl[s ! pressure 9 ! tunnel w\ld drop f #b to #h lb41 & x g5]ally took "s h\rs to raise ! pressure to :at x 0 be=e ! bl[4 ,dur+ t "t regul> op]ations 7 int]rupt$4 ,9 ! latt] "p ( ,june a p]mit 0 obta9$ all[+ ! clay blanket to be increas$ 9 ?ickness up to a dep? ( wat] ( #bg ft4 at mean l[ tide4 ,! additional blanket 0 deposit$ dur+ ! latt] "p ( ,june & e>ly 9 ,july1 & almo/ entirely /opp$ ! bl[s4 ,by ! end ( ! mon? ! natural clay1 previ\sly describ$1 =m$ ! great] portion ( ! face1 &1 f t "t =w>d1 play$ an important "p 9 r$uc+ ! quantity ( air requir$4 ,dur+ ,april & ! e>ly "p ( ,may ! "w 0 "u ! f]ry racks ( ! ,long ,isl& ,railroad4 ,! blanket _h to be plac$ by dump+ ! clay f :eel-b>r[s ?r\gh holes 9 ! deck+4 ,9 ,tunnel ,a a bottom head+ _h be5 driv5 #bc ft4 9 advance ( ! face at ! "t "w 0 /opp$ at ! end ( #aije4 ,dur+ ! t5 mon?s ( inactivity ! seams 9 ! rock above op5$4 ,! rock surface 0 only f #b to #d ft4 bel[ ! top ( ! cutt+ edge = a di/ance ( ab\t #fj ft4 ,ov] ! rock !re 7 l>ge b\ld]s emb$d$ 9 %>p s&4 ,x 0 an exce$+ly difficult op]ation to remove ! b\ld]s & place ! pol+s )\t />t+ a run4 ,! op5 seams ov] ! bottom head+ also frequ5tly caus$ tr\ble1 z !re 7 num]\s slides ( rock f ! face :i* broke up ! brea/+ & all[$ ! s(t mat]ial f above to run into ! %ield4 ,!re 7 two runs ( f #ej to #ge cu4 yd4 & _m small] ones4 ,footnote ,d3 ,! lead ( ! %ield is ! angul> div]g5ce ( its axis f ! axis ( ! tunnel &1 9 ?is tunnel1 0 measur$ z ! (fset 9 #bc ft4 ,x 0 call$ :5 ! %ield 0 po9t$ upw>d f grade1 & - :5 po9t$ d[nw>d4 ,,guid+ ,,! ,,%ields4 ,little difficulty 0 exp]i5c$ at any "t 9 driv+ ! %ield close to ! desir$ l9e1 b x 0 mu* h>d] to keep x on grade4 ,9 rock section1 :]e ! cradle c\ld be set f> en\gh 9 advance to become h>d be=e ! %ield 0 %ov$ ov] x1 !re 0 no tr\ble :atev]4 ,:]e ! cradle c\ld be plac$ only a v %ort "t be=e x _h to take ! weight ( ! %ield1 ! case 0 q diff]5t4 ,! %ield _h a t5d5cy to settle at ! cutt+ edge1 & :5 once po9t$ d[nw>d x 0 extremely difficult to *ange its direction4 ,x 0 g5]ally accompli%$ by emb$d+ railroad rails or heavy oak plank 9 ! cradle on solid f\ndation4 ,?is (t5 _h to be repeat$ sev]al times be=e x 0 successful4 ,9 s(t gr\nd x 0 mu* easi] to *ange ! direction ( ! %ield1 b1 ow+ to ! v>y+ nature ( ! mat]ial1 x 0 sometimes impossible to det]m9e 9 advance h[ ! %ield %\ld be po9t$4 ,x 0 f\nd by exp]i5ce at ,manhattan t ! iron l9+ rema9$ 9 ! be/ position 9 relation to grade :5 ! und]side ( ! bottom ( ! %ield at ! re> end 0 driv5 on grade ( ! bottom ( ! iron1 b if ! rate ( progress 0 sl[1 x 0 bett] to drive ! %ield a little high]4 ,9 ! head+s f ,long ,isl&1 :i*1 z a rule1 7 9 s(t gr\nd1 ! cutt+ edges ( ! %ields 7 kept f #d to #h 94 high]1 ) respect to ! grade l9e1 ?an ! rails4 ,! %ields w\ld !n usually move p>allel to ! grade l9e1 ?\gh ?is 0 modifi$ consid]ably by ! way ! muck+ 0 done & by ! /iffness ( ! gr\nd at ! bottom ( ! %ield4 ,on ! av]age1 ! %ields 7 %ov$ by f t5 to twelve ( ! bottom jacks1 ) a pressure ( ab\t #d1jjj lb4 p] sq4 94 ,! jacks _h #i-;94 plung]s1 :i* made ! av]age total =ce requir$ to %ove ! %ield #b1hjj1jjj lb4 ,9 ! s(t gr\nd1 :]e %utt]s 7 us$1 all ( ! tw5ty-sev5 jacks 7 frequ5tly us$1 & on sev]al occasions ! pressure exce$$ #f1jjj lb4 p] sq4 94 ,) a unit pressure ( #f1jjj lb4 p] sq4 941 ! total pressure on ! %ield ) all tw5ty-sev5 jacks 9 op]ation 0 #e1aed tons4 ,,injuries ,,to ,,%ields4 ,!re 7 only two in/ances ( damage to ! ess5tial /ructural features ( ! %ields4 ,! mo/ s]i\s 0 9 ,tunnel ,d :]e ! cutt+ edge at ! bottom ( ! %ield 0 =c$ up a slightly slop+ l$ge ( rock4 ,a b[ 0 =m$ 9 ! /eel ca/+ :i* 0 m>k$ly increas$ ) ! next few %oves4 ,"w 0 susp5d$1 & a heavy ca/-/eel pat*1 fill+ out ! b[1 0 atta*$ to ! b5t segm5ts1 z %[n 9 ,fig4 #b1 ,plate ,,lxxiii4 ,no fur!r tr\ble 0 exp]i5c$ ) ! de=m$ portion4 ,! o!r in/ance 0 9 ,tunnel ,b1 f ,long ,isl&1 :]e a some:at simil> b less s]i\s accid5t occurr$ & 0 treat$ 9 a l mann]4 ,bulkheads4--,at ,manhattan1 bulkheads _h to be built ne> ! %afts be=e ! tunnels c\ld be put "u pressure4 ,aft] #ejj ft4 ( tunnel _h be5 built on ea* l9e1 ! second bulkheads 7 con/ruct$4 ,! air pressure betwe5 ! fir/ & second bulkheads 0 !n r$uc$ to betwe5 #ae & #bj lb4 ,:5 ! %ields _h be5 advanc$ = #a1ejj ft41 ! ?ird set ( bulkheads 0 built4 ,ne>ly all ! brok5 plates :i* 7 remov$ 7 locat$ betwe5 ! fir/ & ?ird bulkheads at ,manhattan4 ,be=e und]tak+ ?is op]ation1 ! doors ( ! locks 9 ! ,no4 #c bulkheads 7 rev]s$ to take pressure f ! we/4 ,by ?is means x 0 possible to c>ry on ! "w ( dismantl+ ! %ields "u comp>atively l[ pressure simultane\sly ) ! removal ( ! brok5 plates4 ,at ,long ,isl& ,city ! ro(s ( ! caissons s]v$ ! purpose ( ! ,no4 #a bulkheads4 ,two o!r sets ( bulkheads 7 erect$1 ! fir/ ab\t #ejj ft4 & ! second ab\t #a1ejj ft4 f ! %afts4 ,,settlem5t ,,at ,,surface ,,( ,,gr\nd4 ,! driv+ ( su* portions ( ! riv] tunnels1 ) e>? top1 z 7 "u ! l& section1 caus$ a settlem5t at ! surface v>y+ usually f #c to #f 94 ,! ?ree-/ory brick build+ at ,no4 #dab ,ea/ #cd? ,/reet requir$ ext5sive repairs4 ,?is build+ /ood ov] ! section ( "p e>? & "p rock excavation :]e ! tunnels broke out f ! ,manhattan l$ge & :]e !re 7 a numb] ( runs ( s& into ! %ield4 ,9 fact1 ! voids made by ^? runs ev5tually work$ up to ! surface & caus$ ! pavem5t ( ! alley betwe5 ! build+s to drop #d or #e ft4 ov] a consid]able area4 ,! tunnels also pass$ directly "u ! f]ry bridges & racks ( ! ,long ,isl& ,railroad at ,ea/ #cd? ,/reet4 ,tunnels ,b & ,d 7 con/antly bl[+ at ! "t1 &1 :]e progress 0 sl[1 caus$ s mu* settlem5t t "o ( ! racks _h to be rebuilt4 ,tunnel ,a1 on ! o!r h&1 :]e progress 0 rapid1 caus$ practically no settlem5t 9 ! racks4 ,,clay ,,blanket4 ,z previ\sly m5tion$1 clay 0 dump$ ov] ! tunnels 9 v>y+ dep?s at diff]5t times4 ,a mat]ial 0 requir$ :i* w\ld pack into a compact mass & w\ld n readily erode "u ! influ5ce ( ! tidal curr5ts ( ! riv] & ! escape ( ! great volumes ( air :i* (t5 kept ! wat] 9 ! vic9ity ( ! %ields 9 viol5t motion4 ,suitable clay c\ld n be f\nd 9 ! imm$iate vic9ity ( ! "w4 ,mat]ials f ,%oot]'s ,isl& & f ,hav]/raw 7 tri$ = ! purpose4 ,! ,gov]nm5t au?orities did n approve ( ! =m]1 & ! great] portion ( t us$ came f ! latt] po9t4 ,al?\gh a numb] ( diff]5t p]mits gov]n+ ! "w 7 grant$1 !re 7 ?ree important ones4 ,! fir/ p]mit all[$ a blanket :i* r\ghly foll[$ ! pr(ile ( ! tunnels1 ) an av]age ?ickness ( #aj ft4 on ! ,manhattan side & some:at less on ! ,long ,isl& ,city side4 ,! second g5]al p]mit all[$ ! blanket to be built up to a plane #bg ft4 bel[ l[ wat]4 ,?is prov$ effective 9 *eck+ ! t5d5cy to bl[1 b all[$ consid]able loss ( air4 ,f9ally1 dump+ 0 all[$ ov] limit$ & m>k$ areas up to a plane ( #bj ft4 bel[ l[ wat]4 ,:]ev] advantage 0 tak5 ( ?is la/ au?ority1 ! excessive loss ( air 0 almo/ entirely /opp$4 ,aft] all ! %ields _h be5 well advanc$ out into ! riv]1 ! blanket beh9d !m 0 dr$g$ up1 & ! clay us$ ov] aga9 9 advance ( ! %ield4 ,s\nd+s 7 tak5 daily ov] ! %ields1 &1 if m>k$ erosion 0 f\nd1 clay 0 dump$ into ! hole4 ,:5ev] a s]i\s bl[ occurr$1 a sc[load ( clay 0 dump$ ov] x z soon z possible & )\t wait+ to make s\nd+s4 ,= ! latt] purposes a consid]able quantity ( clay 0 plac$ 9 /orage 9 ! ,pidgeon ,/reet slip at ,long ,isl& ,city1 & "o or two bottom-dump sc[s 7 kept fill$ ready = em]g5cies4 ,mr4 ,rob]t ,*alm]s1 :o _h *>ge ( ! s\nd+s = ! contractor1 /ates t ! depressions 9 ! blanket caus$ by erosion due to ! escape ( air 71 z a rule1 r\ghly circul> 9 plan & ( a curv$ section some:at flat 9 ! c5t]4 ,satisfactory s\nd+s 7 nev] obta9$ 9 ! c5t] ( a viol5t bl[1 b ! foll[+ in/ance illu/rates 9 a measure :at occurr$4 ,ov] ,tunnel ,b1 at ,/ation #ajbhj1 !re 0 normally #cf ft4 ( wat]1 #g ft4 ( clay blanket1 & #bj ft4 ( natural cov]4 ,air 0 escap+ at ! rate ( ab\t #aj1jjj cu4 ft4 p] m941 & small bl[s 7 occurr+ once or twice daily4 ,on ,june #bb;d1 s\nd+s %[$ #ed ft4 ( wat]4 ,a dep? ( #ah ft4 ( ! riv] bottom _h be5 erod$ 9 ab\t two days4 ,on ! next day !re 7 tak5 out ( ! %ield b\ld]s :i* _h almo/ c]ta9ly be5 deposit$ on ! natural riv] b$4 ,clay f ! blanket also came into ! %ields on a numb] ( occasions dur+ or aft] bl[s4 ,! mo/ notable occasion 0 9 ,septemb]1 #aijg1 :5 ! top ( ! %ield 9 ,tunnel ,d 0 em]g+ f ! ea/ side ( ,blackwell's ,isl& ,reef4 ,! s& 9 ! top 0 v co>se & loose1 & all[$ ! air to escape v freely4 ,! fall ( a piece ( loose rock f "u ! brea/ precipitat$ a run ( s& :i* 0 foll[$ by clay f ! blanket1 :i*1 9 ?is locality1 0 l>gely ! s(t] r$r$g$ mat]ial4 ,muck+ out ! %ield 0 9 progress :5 ! s(t clay />t$ fl[+ aga9 & =c$ its way back into ! tunnel = a di/ance ( #bj ft41 z %[n 9 ,fig4 #c1 ,plate ,,lxxiii4 ,t5 days ( c>eful & ardu\s "w 7 requir$ to rega9 control ( ! face & complete ! %ove1 on acc\nt ( ! heavy pressure ( ! pla/ic clay4 ,! clay blanket 0 ( ! utmo/ importance to ! "w ?r\gh\t1 & x is difficult to see h[ ! tunnels c\ld h be5 driv5 ?r\gh ! s(t mat]ial on ! ,manhattan side )\t x4 ,! new mat]ial us$ 9 ! blanket am\nt$ to #bhc1dab cu4 yd41 ( :i* #aag1hdf cu4 yd4 7 remov$ f ov] ! complet$ tunnels & r$eposit$ 9 ! blanket 9 advance ( ! %ields4 ,a total ( #hh1jei cu4 yd4 ( clay 0 dump$ ov] bl[s4 ,! total co/ ( plac+ & remov+ ! blanket 0 #cjd1jef4 ,,iron ,,l9+4 ,! /&>d ca/-iron tunnel l9+ 0 ( ! usual tube type1 #bc ft4 9 outside diamet]4 ,! r+s 7 #cj 94 wide1 & 7 compos$ ( elev5 segm5ts & a key4 ,! webs ( ! segm5ts 7 #a-a_/b 94 ?ick 9 ! c5tral portion1 increas+ to #b-c_/h 94 at ! roots ( ! flanges1 :i* 7 #aa 94 deep1 #b-a_/d 94 ?ick at ! root1 & #a-a_/b 94 at ! edge1 & 7 ma*9$ on all contact faces4 ,recesses 7 ca/ 9 ! edge ( ! flanges1 =m+ a groove1 :5 ! l9+ 0 9 place1 #a-a_/b 94 deep & ab\t #c_/h 94 wide1 to receive ! caulk+4 ,! bolt holes 7 cor$ 9 ! flanges1 & ! bosses fac+ ! holes 7 n ma*9$4 ,! cu/om>y gr\t hole 0 tapp$ 9 ! c5t] ( ea* plate = a /&>d #a-a_/d-;94 pipe4 ,9 ?is "w1 exp]i5ce indicat$ t ! /&>d pipe ?read 0 too f9e1 & t ! tap] 0 objectionable4 ,ea* segm5t weigh$1 approximately1 #b1jbj lb41 & ! key weigh$ #ebj lb41 ! total weight be+ #i1ajb lb4 p] l94 ft4 ( tunnel4 ,fig4 #a %[s ! details ( ! /&>d heavy l9+4 ,9 addition to ! /&>d ca/-iron l9+1 ca/-/eel r+s ( ! same dim5sions 7 provid$ = use 9 a %ort /ret* ( ! tunnel1 :5 pass+ f a rock to a s(t gr\nd f\ndation1 :]e x 0 anticipat$ t unequal settlem5t & consequ5t di/ortion & increase 9 /ress might occur1 b1 aside f ! small regul> drop ( ! l9+ z x pass$ out ( ! tail ( ! %ield1 no su* settlem5t 0 obs]v$4 ,two classes ( light] iron1 "o ) #a-;94 web & #h-;94 flanges & ! o!r ) #a-a_/d-;94 web & #i-;94 flanges--! =m] weigh+ #e1aff lb4 p] l94 ft4 ( tunnel & ! latt]1 #f1ggf lb4--7 provid$ = use 9 ! l& sections betwe5 ,ea/ ,av5ue & ! ,long ,isl& ,city %afts4 ,two weights ( extra heavy segm5ts = use at ! bottom ( ! r+s 7 also furni%$4 ,! s-call$ ,,xx plates _h webs & flanges #a_/d 94 ?ick] ?an ! /&>d segm5t & ! ,,yy plates 7 simil>ly #a_/b 94 heavi]4 ,! conditions "u :i* !y 7 us$ w be ref]r$ to lat]4 ,all ! ca/+s 7 ( ! same g5]al type z %[n by ,fig4 #a4 ,r+s tap]+ #c_/d 94 & #a-a_/b 94 9 wid? 7 us$ = *anges 9 alignm5t & grade1 ! =m] be+ us$ approximately at e f\r? r+ on ! #a #cj' curves4 ,! #a-a_/b-;94 tap]s 7 l>gely us$ = *anges 9 grade :]e x 0 desir$ to free ! iron f b9d+ on ! tail ( ! %ield4 ,/ill wid] tap]s w\ld h be5 advantage\s = quick results 9 ?is respect4 ,no lug 0 ca/ on ! segm5ts = atta*m5t to ! erector1 b 9 its place ! gadget %[n on ,fig4 #d1 ,plate ,,lxx1 0 ins]t$ 9 "o ( ! pairs ( bolt holes ne> ! c5t] ( ! plate1 & 0 held 9 position by ! runn+ nut at "o end4 ,9 ! beg9n+ x 0 expect$ t ! natural %ape ( ! r+s w\ld n %[ m ?an #a 94 ( %ort5+ ( ! v]tical diamet]2 ?is 0 slightly exce$$1 h[ev]1 ! av]age di/ortion ?r\gh\t ! tunnels be+ #a-g_/af 94 ,! erectors 7 atta*$ to ! %ield & 9 su* a position t !y 7 9 ! plane ( ! c5t] ( ! r+ to be erect$ :5 ! %ove 0 made )\t lead & j f> en\gh to p]mit plac+ ! segm5ts4 ,if ! %ield 7 %ov$ too f>1 a r>e occurr5ce1 ! erection 0 inconv5i5c$4 ,9 driv+ ) high v]tical leads1 :i* occurr$ m frequ5tly1 ! disadvantage ( plac+ ! erector on ! %ield 0 m app>5t4 ,"u su* conditions ! plane ( ! erector's motion 0 acutely incl9$ to ! plane ( ! r+1 &1 aft] plac+ ! l[] portion ( ! r+1 x 0 usually necess>y to %ove ! %ield a few in*es f>!r 9 ord] to place ! upp] plates4 ,! practical effect ( ?is action is ref]r$ to lat]4 ,illu/ration3 ,,fig4 #a4 ,at fir/ ! erection ( ! iron 9 ! riv] tunnels int]f]$ some:at ) ! muck+ op]ations1 b ! l5g? ( "t requir$ to complete ! latt] 0 ample = ! completion ( ! =m]2 & ! />t+ ( a %ove 0 seldom po/pon$ by reason ( ! non-completion ( a r+4 ,aft] ! removal ( ! bottom ( ! diaphragms1 p]mitt+ ! muck c>s to be run into ! %ield & beyond1 ! two op]ations 7 c>ri$ on simultane\sly )\t s]i\s int]f]5ce4 ,! in/allation ( ! belt conveyor = h&l+ ! s(t gr\nd spoil 9 ,tunnel ,a 0 ( special b5efit 9 ?is respect4 ,prep>atory to ! f9al bolt tight5+ ( ea* r+ z erect$1 a #ae-ton draw-jack1 consi/+ ( a small pull+-jack ins]t$ 9 a light eye-b> *a91 0 plac$ on ! horizontal diamet]1 & frequ5tly ! erectors 7 also us$ to boo/ ! cr[n ( ! iron1 ! object be+ to erect ! r+ truly circul>4 ,be=e %ov+1 a #a-a_/d-;94 turn-buckle 0 also plac$ on ! horizontal diamet] 9 ord] to prev5t ! spread+ ( ! iron1 previ\s to fill+ ! void outside ) gr\t4 ,! approa* ( ! supports = ! upp] floor ( ! trail+ plat=m necessitat$ ! removal ( ^! turnbuckles f all b ! ?ree lead+ r+s1 b if ! iron %[$ a t5d5cy to cont9ue di/ortion1 !y 7 re-ins]t$ aft] ! passage ( ! trail+ plat=m & rema9$ until ! ar* ( ! concrete l9+ 0 plac$4 ,! co/ ( h&l+ & erect+ ! iron v>i$ greatly at diff]5t times1 av]ag+1 = ! riv] tunnels1 #c4cb p] ton = ! directly *>geable labor ( h&l+ & erect+1 to :i* mu/ be add$ #g4ed = top *>ges4 ,! co/ ( repair+ brok5 plates is includ$ 9 ?is figure4 ,brok5 ,plates4--,dur+ ! con/ruction ( ! riv] section ( ! tunnels1 a numb] ( segm5ts 7 f\nd to h be5 brok5 :ile %ov+ ! %ield4 ,! breaks1 :i* ) few exceptions 7 conf9$ to ! ?ree or f\r bottom plates1 almo/ inv>iably occurr$ on ! advanc$ face ( ! r+1 & r>ely ext5d$ beyond ! bottom ( ! flange4 ,a c>eful /udy ( ! breaks & ( ! %ov+ records disclos$ sev]al di/9ct types ( fracture & ?ree pr9cipal kn[n causes ( breakage by ! %ield4 ,9 ! fir/ case1 ! accid5tal intrusion ( =eign mat]ial betwe5 ! jack head & ! iron caus$ ! jack to take its be>+s on ! flange above its normal position opposite ! web ( ! r+1 & result$ usually 9 ! break+ out ( a piece ( ! flange or 9 sev]al radiat+ cracks ) or )\t a depression ( ! flange4 ,^! breaks 7 v *>act]i/ic1 & ! cause 0 readily recognizable1 ev5 ?\gh ! intrud+ sub/ance 0 n actually obs]v$4 ,9 ! second case1 ! work+ ( a h>d piece ( metal1 su* z a small tool1 into ! annul> space betwe5 ! iron & ! tail ( ! %ield1 :]e x 0 caught on ! bead & dragg$ along z ! %ield advanc$1 0 ! kn[n cause ( a numb] ( brok5 segm5ts4 ,su* breaks _h no p>ticul> *>act]i/ic1 b 7 usually close above ! l9e ( travel ( ! lo/ tool or metal4 ,_! cause 0 det]m9$ by ! f9d+ ( a heavy score on ! und]side ( ! segm5t or ! discov]y ( ! tool w$g$ 9 ! tail ( ! %ield or ly+ "u ! brok5 plate :5 x 0 remov$4 ,x is probable t a numb] ( breaks ascrib$ to unkn[n causes %\ld be plac$ 9 ?is class4 ,! ?ird cause includes ! l>ge/ numb] ( breaks1 &1 :ile difficult to def9e closely1 is ! mo/ int]e/+4 ,broadly speak+1 ! breaks result$ f ! movem5ts ( ! %ield 9 relation to ! position ( ! tunnel l9+4 ,:ile %ov+ ?r\gh s(t gr\nd1 x 0 frequ5tly difficult to apply suffici5t p[] to ! l[] jacks to complete ! full %ove ( #cj 94 on ! desir$ alignm5t4 ,! %ield1 !re=e1 0 driv5 upw>d at ! beg9n+ ( ! %ove1 &1 z ! s& pack$ 9 front ( ! %ield & m p[] 0 requir$1 x 0 furni%$ by apply+ ! upp] jacks4 ,! top ( ! %ield 0 sl[ly pu%$ ov]1 &1 at ! close ( ! %ove1 ! desir$ position _h be5 obta9$2 b ! %ield _h be5 giv5 a rock+ motion ) a decid$ lift+ ( ! tail t[>d ! close ( ! %ove4 ,a simil> lift+ ( ! tail occurr$ :51 ) high v]tical leads1 ! top ( ! %ield 0 pu%$ ov] 9 ord] to place ! upp] plates ( ! r+4 ,aga91 :5 ! %ield 0 driv5 above grade & x 0 desir$ to desc5d1 ! passage ( ! %ield ov] ! summit produc$ a l effect4 ,9 all ^! movem5ts1 ) ! space betwe5 ! tail ( ! %ield & ! iron pack$ tight ) pugg+1 ! upw>d ?ru/ ( ! %ield t5d$ to flatt5 ! iron 9 ! bottom & occasional brok5 plates 7 ! result4 ,! free use ( ! tap] r+s1 plac$ s z to relieve ! b9d+ ( ! l9+ on ! tail ( ! %ield1 =ces ! tunnel to foll[ ! v>iations 9 ! grade ( ! %ield1 b r$uces greatly ! injuries to ! r+s f ?is action4 ,9 ,tunnel ,d1 :]e v high v]tical leads 7 requir$ ?r\gh ! s(t s&1 comb9$ ) a m>k$ t5d5cy ( ! %ield to settle1 ! %ield 0 badly cramp$ on ! iron & dragg$ along x at ! top4 ,! be>+ ( ! iron on its s(t f\ndation t5d$ to ?ru/ up ! bottom 9 ?is case also1 z %[n by ! op5+ ( ! bottom cross-jo9ts :5 ! bolts 7 slack5$ to relieve ! /ra9 dur+ a %ove4 ,! anticipat$ cracks 9 ! cr[n plates1 :i* h be5 m frequ5tly obs]v$ 9 o!r tunnels1 did n occur "h1 & 7 n f\nd else:]e except 9 "o place 9 ,tunnel ,b :]e !y 7 trac$ to a simil> action ( ! %ield4 ,! cracks result+ f ! movem5ts ( ! %ield1 z briefly describ$ above1 9 ?is ?ird case 7 n conf9$ to any p>ticul> type1 b occurr$ m frequ5tly at ! extreme end ( ! circumf]5tial flange ?an at any o!r po9t4 ,! numb] ( brok5 plates occurr+ 9 ! riv] tunnels 0 #cai1 or #j4db ( ! total numb] erect$4 ,( ^!1 #eb 7 f\nd & remov$1 ei!r be=e or imm$iately aft] a %ove1 by f> ! great] numb] be+ brok5 9 h&l+ be=e or dur+ erection4 ,! rema9+ #bfg are consid]$ bel[4 ,repair ( ,brok5 ,plates4--,on ! completion ( a %ove1 ! tail ( ! %ield lack$ ab\t #e 94 ( cov]+ ! full wid? ( ! la/ r+1 & ! removal ( a plate brok5 dur+ ! %ove1 !re=e1 w\ld h expos$ ! gr\nd at ! tail ( ! %ield4 ,) a firm mat]ial 9 ! bottom1 ?is introduc$ no p>ticul> difficulties1 &1 "u su* conditions1 a brok5 plate 0 usually remov$ at once4 ,9 ! s&1 h[ev]1 & especially on ! ,manhattan side :]e x 0 quick & fl[+1 ! removal ( a plate 0 att5d$ ) "s dang]1 & su* plates 7 usually left to be remov$ on ! completion ( ! tunnel4 ,_m ( ^! _h be5 re9=c$ by ! use ( ,,xx1 ,,yy1 & /eel segm5ts plac$ adjac5t to ! break 9 ! foll[+ r+s4 ,aft] ! meet+ ( ! %ields1 ! po/pon$ replacem5t ( ! brok5 segm5ts 0 tak5 up4 ,! pressure 0 rais$ suffici5tly to dry ?or\ghly ! s& outside ! segm5ts1 :i* 7 drill$ & brok5 out usually 9 qu>t]s z %[n on ,fig4 #a1 ,plate ,,lxxiii4 ,a /eel segm5t 0 !n ins]t$ 9 ! r+ & drawn into place by turnbuckles4 ,! application ( ! draw-jack1 ) a pull ( ab\t #cj tons to ea* end successively1 br\ght ! plate to a firm be>+ on ! radial jo9ts at ! ends4 ,:]e ! brok5 plate 0 isolat$ & 0 re9=c$ by /eel or extra heavy segm5ts 9 ! adjac5t r+1 ! crack1 if slight1 0 simply caulk$ to insure wat]-tightness4 ,if1 h[ev]1 ! crack 0 op5$ or ext5d$ to ! web ( ! plate1 ! cross-flanges 7 ti$ toge!r by a #a-a_/b-;94 by #g-;ft4 bolt1 ins]t$ ?r\gh ! bolt holes ne>e/ ! brok5 flange4 ,! long bolt act$ 9 ! nature ( a b[ /r+1 & 0 provid$ at its ends ) two nuts set on opposite sides ( ! cross-jo9ts to replace ! /&>d bolts remov$ = its ins]tion4 ,fig4 #d1 ,plate ,,lxxiii %[s "o ( ^! bolts 9 place4 ,9 addition1 all brok5 plates rema9+ 9 ! tunnel 7 re9=c$ ) #a-;94 twi/$-/eel rods 9 ! concrete l9+1 also %[n 9 ,fig4 #d1 ,plate ,,lxxiii4 ,special ,con/ruction at ,riv] ,%ield ,junctions4--,dismantl+ ! %ields 0 />t$ z soon z !y came to re/ 9 _! f9al position ) ! cutt+ edges toge!r4 ,! plans contemplat$ _! entire removal1 ) ! exception ( ! cyl9drical sk9s & ca/-/eel cutt+ edges4 ,inside ! =m] ! /&>d tunnel l9+ 0 erect$ to )9 #d ft4 ( ! heels ( ! cutt+ edges4 ,spann+ ! latt]1 & =m+ ! cont9u\s metal tunnel l9+1 ! special con/ruction %[n by ,fig4 #b 0 built4 ,?is consi/$ ( a #a-a_/d 94 roll$-/eel r+1 #g ft4 long1 erect$ inside ! cutt+ edges1 ) an annul> cle>ance ( #a 941 & two special ca/-iron r+s %ap$ to connect ! roll$-/eel r+ ) ! normal l9+4 ,"o flange ( ! special ca/-iron r+s 0 ( ! /&>d type1 ! o!r 0 return$ #i 94 9 ! =m ( a r+1 ! inside diamet] ( :i* 0 ! same z ! outside diamet] ( ! roll$-/eel r+ to :i* x 0 bolt$4 ,! space betwe5 ! /&>d & special con/ruction 0 ( v>y+ wid? at ! v>i\s %ields1 & 0 fill$ ) a closure r+ ca/ to ! l5g?s det]m9$ 9 ! field4 ,fig4 #b %[s ! complet$ con/ruction4 ,hook-bolts1 screw$ ?r\gh ?read$ holes & buri$ 9 #a to #a ,portl& cem5t gr\t eject$ ?r\gh simil> holes1 re9=c$ ! roll$-/eel r+ aga9/ ext]nal wat] pressure4 ,9 two ( ! tunnels ! concrete l9+ 0 c>ri$ completely ?r\gh ! junction1 & cov]$ ! :ole con/ruction1 :ile 9 ! rema9+ two tunnels x 0 omitt$ at ! roll$-/eel r+1 leav+ ! latt] expos$ & set back ab\t #c 94 f ! face ( ! concrete4 ,illu/ration3 ,,fig4 #b4 ,,gr\t+4 ,except z previ\sly not$1 ! voids outside ( ! tunnel l9+ 7 fill$ ) gr\t eject$ ?r\gh ! gr\t holes 9 ea* segm5t4 ,! possibility 0 always pres5t t ,portl& cem5t1 if us$ = gr\t 9 ! %ield-driv5 tunnels1 w\ld fl[ =w>d ar\nd ! %ield & set h>d1 freez+ ! %ield to ! rock or ! iron l9+1 or at lea/ =m+ excresc5ces ^u x1 :i* w\ld r5d] its control difficult4 ,) ?is 9 m9d1 ! contractors propos$ to sub/itute an ,engli% ,blue ,lias lime z a gr\t+ mat]ial4 ,gr\t ( fre% ,engli% lime conta9+ a mod]ate quantity ( wat] set v rapidly 9 air to ! consi/5cy ( *alk4 ,its hydraulic prop]ties1 h[ev]1 7 feeble1 & 9 ! pres5ce ( an excess ( wat] x rema9$ at ! consi/5cy ( s(t mud4 ,x 0 n suitable1 !re=e1 z a support+ mat]ial = ! tunnel4 ,an ,am]ican lime1 made 9 imitation ( ! ,lias lime1 b hav+ great] hydraulic prop]ties1 0 tri$1 b prov$ unsatisfactory4 ,two br&s ( natural cem5t 7 also tri$ & reject$1 b a modifi$ quick-sett+ natural cem5t1 manufactur$ especially = ?is "w1 0 ev5tually made satisfactory1 & by f> ! l>ge/ "p ( ! riv]-tunnel gr\t+ 0 done ) ?is mat]ial mix$ #a to #a by volume4 ,ea/ ( ! ,long ,isl& %afts ! "w :i* 0 built )\t %ields 0 gr\t$ pr9cipally ) ,portl& cem5t & s& mix$ #a to #a by volume4 ,9 ! riv] tunnels l>ge quantities ( ! ,engli% lime 7 us$ neat z gr\t ov] ! top ( ! tunnel 9 attempts to /op losses ( air ?r\gh ! s(t gr\nd4 ,x 0 n ( great effici5cy1 h[ev]1 9 ?is respect until ! voids outside ( ! l9+ _h be5 fill$ above ! cr[n4 ,its prop]ties ( swell+ & quick sett+ 9 ! dry s& at t po9t !n became ( value4 ,! use ( dry lime 9 ! face1 :]e ! escap+ air w\ld c>ry x into ! voids ( ! s& & *oke !m1 0 mu* m promptly efficaci\s 9 *eck+ ! loss4 ,) ! exception ( ! ,engli% lime1 all gr\t 0 mix$ #a to #a ) s& 9 a ,cockburn cont9u\s-/irr+ ma*9e op]at$ by a #c-;cyl9d] air eng9e4 ,! gr\t ma*9e 0 plac$ on ! l[] floor ( ! trail+ plat=m %[n on ,plate ,,lxxii1 :ile ! mat]ials 7 plac$ on ! upp] plat=m1 &1 toge!r ) ! wat]1 7 f$ into ! ma*9e ?r\gh a hole 9 ! upp] floor4 ,! s& 0 bagg$ 9 ! y>d1 & ! c>s on :i* ! mat]ials 7 s5t into ! tunnels 7 lift$ by an elevator to ! level ( ! upp] floor ( ! trail+ plat=m be=e unload+4 ,great difficulty 0 exp]i5c$ 9 prev5t+ ! wa/e ( ! fluid gr\t ahead ( ! %ield & into ! tail ?r\gh ! space betwe5 x & ! iron l9+4 ,9 a full s(t gr\nd section1 ! fir/ condition did n usually arise4 ,9 ! full-rock sections ! mo/ effici5t me?od ( *eck+ ! wa/e 0 f\nd to be ! con/ruction ( dams or bulkheads outside ! l9+ betwe5 x & ! rock surface4 ,= ?is purpose1 at int]vals ( ab\t #cj ft41 ! lead+ r+ & ! upp] half ( ! prec$+ "o 7 disconnect$ & pull$ =w>d suffici5tly to give access to ! ext]ior4 ,a r\gh dam ( rubble1 or bags ( mort> or clay1 0 !n con/ruct$ outside ! iron1 & ! r+s 7 %ov$ back & connect$ up4 ,9 sections conta9+ bo? rock & s(t gr\nd1 gr\t dams 7 built at ! cutt+ edge at int]vals1 & 7 c>ri$ up z high z circum/ances p]mitt$4 ,! annul> space at ! tail ( ! %ield 0 at all times suppos$ to be pack$ tight ) clay & empty bags1 b ! pugg+ 0 difficult to ma9ta9 aga9/ ! pressure ( ! gr\t4 ,= a "t1 #a_/b-;94 segm5tal /eel plates1 slipp$ d[n betwe5 ! jackets & ! iron1 7 us$ to reta9 ! pugg+1 b _! displacem5t result$ 9 a numb] ( brok5 flanges1 & _! use 0 ab&on$4 ,9 _! place1 #b-;94 segm5tal plates atta*$ to ! jack heads 7 sub/itut$ ) m satisfactory results4 ,not)/&+ ^! devices1 ! wa/e ( gr\t at ! tail 0 v great4 ,! s(t gr\nd mat]ial on v>i\s portions ( ! "w act$ v diff]5tly4 ,! clay & bull's liv] did n cave 9 ^u ! iron l9+ = sev]al h\rs aft] ! %ield _h pass$1 sometimes n = a day or m1 :i* p]mitt$ ! space betwe5 x & ! iron to be gr\t$4 ,! f9e gray or bea* s& & ! quicks& clos$ 9 almo/ at once4 ,! quicks& has a t5d5cy to fill 9 "u ! iron f ! sides & 9 places to leave a cavity at ab\t ! horizontal diamet] :i* 0 n fill$ f above1 z ! s&1 be+ dri$ out by ! air1 /ood up fairly well & did n cave aga9/ ! iron1 except :]e ne>ly horizontal at ! top4 ,! total quantity ( gr\t us$ on ! "w 0 equival5t 9 set volume to #bdi1fdg bbl4 ( #a to #a ,portl& cem5t gr\t1 ( :i* #bcc1fdg bbl4 7 eject$ ?r\gh ! iron l9+1 an av]age ( #ad4ic bbl4 p] l94 ft4 ,! co/ ( gr\t eject$ outside ( ! riv] tunnels 0 #ic c5ts p] bbl4 = labor & #b4gg = top *>ges4 ,ea/ ( ! ,long ,isl& %aft ! correspond+ co/s 7 #j4fh & #a4fc1 ! diff]5ce be+ p>tly due to ! l>ge p]c5tages ( "w done 9 ! normal air at ! latt] place4 ,,caulk+ ,,& ,,leakage4 ,up to ,augu/1 #aijg1 ! jo9ts betwe5 ! segm5ts ( ! ca/-iron l9+ 7 caulk$ ) iron fil+s & sal ammoniac1 mix$ 9 ! proportion ( #djj to #a by weight4 ,) ! air pressure balanc+ ! hydro/atic head ne> ! tunnel axis1 x 0 difficult to make ! ru/-jo9t caulk+ tight bel[ ! axis aga9/ ! oppos+ wat] pressure2 ?is =m ( caulk+ 0 also injur$ 9 _m places by wat] dripp+ f s]vice pipes atta*$ to ! tunnel l9+4 ,a few trials ( lead wire caulk$ cold gave su* satisfactory results t x 0 adopt$ z a sub/itute4 ,pneumatic hamm]s 7 us$ successfully on ! lead caulk+1 b 7 only us$ to a small ext5t on ! ru/ bor+s1 :i* 7 mo/ly h& caulk$4 ,imm$iately be=e plac+ ! concrete l9+1 all leaks1 :e!r 9 ! ru/ bor+s or lead1 7 repair$ ) lead1 & ! rema9d] ( ! groove 0 fill$ ) #a to #a ,portl& cem5t mort>1 leav+ ! jo9ts absolutely wat]-tight at t "t4 ,! subsequ5t developm5t ( small seepages ?r\gh ! concrete w\ld seem to indicate t ! repair "w %\ld h be5 c>ri$ on f> en\gh 9 advance ( ! concret+ to p]mit ! detection ( second>y leaks :i* might develop sl[ly4 ,! av]age labor co/ *>geable aga9/ ! caulk+ 0 #ab c5ts p] l94 ft41 to :i* %\ld be add$ #ba4h c5ts = top *>ges4 ,un=tunately1 x 0 necess>y to place ! great] "p ( ! concrete l9+ 9 ! riv] tunnels dur+ ! summ] mon?s :5 ! temp]ature at ! po9t ( "w frequ5tly exce$$ #he2 & ! temp]ature ( ! concrete :ile sett+ 0 mu* high]4 ,?is abnormal heat1 due to *emical action 9 ! cem5t1 soon pass$ away1 &1 ) ! approa* ( w9t]1 ! contraction ( ! concrete result$ 9 transv]se cracks4 ,by ! middle ( ! w9t] ^! _h develop$ q uni=mly at ! ends ( ea* #cj-;ft4 section ( concrete ar* z plac$1 & frequ5tly f9] cracks %[$ at ab\t ! c5t] ( ea* #cj-;ft4 section4 ,:ile ! temp]ature ( ! concrete 0 fall+1 a l *ange 0 tak+ place 9 ! ca/-iron l9+1 ) result+ contraction4 ,! l9+ _h be5 erect$ 9 compress$ air1 ! temp]ature ( :i* av]ag$ ab\t #gj 9 w9t] & high] 9 summ]4 ,compress$ air hav+ be5 tak5 (f 9 ! summ] ( #aijh1 ! tunnels !n acquir$ ! l[] temp]ature ( ! surr\nd+ e>?1 sl[ly fall+ until mid-w9t]4 ,! contraction ( ! concrete1 firmly b$d$ ar\nd ! flanges ( ! iron1 & %[+ cracks at fairly uni=m int]vals1 probably localiz$ ! small correspond+ movem5ts ( ! iron ne> ! concrete cracks1 & result$ 9 a loos5+ ( ! caulk+ at ^! po9ts4 ,) ! adv5t ( cold wea!r1 damp spots appe>$ 9 num]\s places on ! concrete1 & small seepages %[$ ?r\gh q regul>ly at ! temp]ature cracks1 9 "s cases develop+ suffici5tly to be call$ leaks4 ,only a few1 h[ev]1 7 measurable 9 am\nt4 ,e>ly 9 ,janu>y small brass plugs 7 firmly set on opposite sides ( a l>ge numb] ( cracks1 & calip] read+s & air temp]ature obs]vations 7 tak5 regul>ly ?r\gh\t ! w9t] & spr+4 ,! wid?s ( ! cracks & ! am\nt ( leakage at !m increas$ ) ea* drop 9 temp]ature & decreas$ z ! temp]ature rose aga91 b until spr+ ! wid? ( ! cracks did n return to ! same po9t ) ea* return ( temp]ature4 ,! leakage 0 simil> 9 all f\r tunnels1 b 0 l>ge/ 9 am\nt 9 ,tunnel ,d1 :]e1 at ! beg9n+ ( ,febru>y1 ! ord9>y fl[ 0 ab\t #j4jjig cu4 ft4 p] sec41 equival5t to #j4jjjjjcdg cu4 ft4 p] sec4 p] l94 ft4 ( tunnel4 ,( ?is am\nt #j4jjfe cu4 ft4 p] sec4 c\ld be acc\nt$ = at eight ( ! cracks %[+ measurable leakage1 leav+ #j4jjcb cu4 ft4 p] sec4 or #j4jjjjjjha cu4 ft4 p] sec4 p] l94 ft4 ( tunnel to be acc\nt$ = z g5]al seepage di/ribut$ ov] ! :ole l5g?4 ,x 0 n feasible to /op e leak 9 ! tunnel1 mo/ ( :i* 7 indicat$ simply by damp spots on ! concrete2 a r simple me?od 0 devis$1 h[ev]1 = /opp+ ! leaks at ! eight or t5 places 9 ea* tunnel :]e wat] dripp$ f ! ar* or fl[$ d[n ! face ( ! concrete4 ,! wor/ leak 9 any tunnel fl[$ ab\t #j4jjbc cu4 ft4 p] sec4 ,to /op ^! leaks1 r[s ( #a-;94 holes1 at ab\t #d-;94 c5t]s1 7 drill$ ) jap drills ?r\gh ! concrete to ! flange ( ! iron4 ,^! r[s 7 f #c to #ah ft4 long1 ext5d+ #a ft4 or m beyond ! limits ( ! leak4 ,! bottoms ( ! holes 7 directly on ! caulk+ groove & ! p\nd+ ( ! drill usually drove ! caulk+ back1 s t ! leak became dry or ne>ly s aft] ! holes 7 drill$4 ,if left alone ! leaks w\ld gradually break out aga9 9 a few h\rs or a few days & fl[ m wat] ?an be=e4 ,!y 7 all[$ to d ?is1 h[ev]1 9 only a few cases z exp]im5ts4 ,aft] ! holes 7 drill$1 ! bottom #d 94 next ! flange 0 fill$ ) s(t neat cem5t mort>4 ,imm$iately on top ( ?is 0 plac$ two plugs ( neat cem5t ab\t #b-a_/b 94 long1 :i* 7 #e or #f h\rs old & r h>d4 ,ea* 0 tamp$ 9 ) a r\nd caulk+ tool ( ! size ( ! hole driv5 ) a sl$ge hamm]4 ,on top ( ?is 7 driv5 9 ! same way two m plugs ( neat cem5t ( ! same size1 :i* 7 h>d set4 ,^! broke up "u ! bl[s ( ! hamm]1 & caulk$ ! hole tight4 ,:5 f9i%$1 ! tamp+ tool w\ld r+ z ?\gh x 0 9 solid rock4 ,great pressure 0 ex]t$ on ! pla/ic mort> 9 ! bottom ( ! hole1 :i* result$ 9 ! re-caulk+ ( ! jo9t ( ! iron4 ,no fur!r measurable leakage develop$ 9 ! repair$ cracks1 dur+ a p]iod ( f\r mon?s1 & ! total leakage has be5 r$uc$ to ab\t #j4jjb cu4 ft4 p] sec4 9 ea* tunnel1 an av]age ( #j4jjjjjjea cu4 ft4 p] sec4 p] l94 ft4 ,,sump ,,& ,,pump ,,*amb]s4 ,to take c>e ( ! dra9age ( ! tunnels1 a sump ) a pump *amb] above x 0 provid$ = ea* pair ( tunnels4 ,! sumps 7 really %ort tunnels und]nea? ! ma9 ones & ext5d+ approximately betwe5 ! c5t] l9es ( ! latt]4 ,!y 7 #aj ft4 #i-a_/b 94 9 outside diamet] & #dd ft4 long4 ,! wat] drops directly f ! dra9s 9 ! c5t] l9es ( ! tunnels into ! sumps4 ,above ! sumps & betwe5 ! tunnels1 a pump *amb] #ai ft4 #e 94 long 0 built4 ,above ! end ( ! latt]1 opposite ! sump1 a cross-passage 0 con/ruct$ betwe5 ! b5* walls ( ! two tunnels4 ,?is passage gives access f ei!r tunnel ?r\gh an op5+ 9 ! floor to ! pump *amb] & ?r\gh ! latt] to ! sump4 ,f ! prelim9>y bor+s x 0 ?\ght t ! sumps 7 locat$ s t ! entire con/ruction w\ld be 9 rock4 ,?is prov$ to be ! case on ,tunnels ,c & ,d1 b n on ,tunnels ,a & ,b4 ,! position ( ! rock surface 9 ! latt] is %[n by ,fig4 #c4 ,aft] ! excavation 0 complet$ 9 ,tunnel ,b1 ,janu>y #a/1 #aijh1 ! plates 7 remov$ f ! side ( ! tunnel at ! cross-passage1 & a drift 0 driv5 ?r\gh ! e>? above ! rock surface across to ! l9+ ( ,tunnel ,a4 ,! head+ 0 timb]$ z %[n by ,fig4 #c4 ,!re 0 practically no loss ( air f ! drift1 b ! clay blanket _h be5 remov$ f ov] ?is locality & ! situation caus$ "s anxiety4 ,9 ord] to make ! head+ z secure z possible1 ! #bd-;94 ,i-beams1 %[n on ,fig4 #c1 7 atta*$ to ! l9+ ( ! two tunnels4 ,! beams =m$ a support = ! p]man5t concrete ro( ar* ( ! passage1 :i* 0 plac$ at once4 ,at ! same "t plates 7 remov$ f ! bottom 9 ,tunnel ,b ov] ! site ( ! sump1 & a head+ 0 />t$ on ! l9e ( ! sump t[>d ,tunnel ,a4 ,z soon z ! head+ _h be5 driv5 beyond ! c5t] l9e ( ! pump *amb]1 a bottom head+ 0 driv5 f a break-up we/w>d 9 ! pump *amb] & a connection 0 made ) ! cross-passage4 ,! iron l9+ ( ! pump *amb] 0 next plac$1 f ! cross-passage ea/w>d4 ,! s(t gr\nd 0 excavat$ directly 9 advance ( ! l9+1 & ! gr\nd 0 support$ by pol+s 9 mu* ! same mann] z describ$ = %ield "w4 ,on acc\nt ( bad gr\nd & seams ( s& enc\nt]$ 9 ! rock bel[ ! level ( ! cross-beams1 ! entire we/ wall ( ! pump *amb] 0 plac$ be=e enl>g+ ! sump to full size4 ,?is 0 also judici\s1 9 ord] to support z f> z possible ! iron l9+ ( ! tunnels4 ,! sump 0 !n excavat$ to full size4 ,! iron l9+ ( ! sump & ! ea/ wall ( ! pump *amb] 7 plac$ z soon z possible4 ,! voids outside ! iron l9+ ( ! sump & ! pump *amb] 7 fill$ z completely z possible ) concrete1 & !n ?or\ghly gr\t$4 ,f9ally1 ! concrete l9+ 0 put 9 place inside ( ! iron4 ,z %[n by ,fig4 #c1 ! excavation ( ^! *amb]s left a consid]able portion ( ! iron l9+ ( ! tunnels tempor>ily unsupport$ on ! l[] inn] qu>t]4 ,to gu>d aga9/ di/ortion1 a sy/em ( diagonals & /ruts 0 plac$ z %[n4 ,! floor ( ! pump *amb] 0 wat]-pro($ ) felt & pit* 9 a mann] simil> to t describ$ = ! caissons at ,long ,isl& ,city4 ,x 0 n possible to make ! felt /ick to ! v]tical walls ) s(t pit*1 :i* 0 ! only k9d t c\ld be us$ 9 compress$ air1 &1 !re=e1 ! surfaces 7 wat]-pro($ by a wall ( asphalt brick laid 9 pit* melt+ at #fj ,fahr4 ,=ms 7 erect$ on ! neat l9e1 & ! space to ! rock 0 fill$ ) concrete mak+ a s-call$ s&-wall simil> to t commonly us$ = wat]-pro(+ ) felt & pit*4 ,! bricks 7 !n laid to a height ( f\r or five c\rses4 ,! jo9ts 7 fill$ ) pit* in/ead ( mort>4 ,%eets ( t9 7 !n plac$ aga9/ ! face ( ! wall & brac$ f ! concrete =ms4 ,z mu* pit* z possible 0 !n slu%$ betwe5 ! brick & ! s&-wall1 aft] :i* ! concrete 9 ! ma9 wall 0 fill$ up to ! top ( ! wat]-pro(+ c\rse4 ,! t9 0 !n )drawn & ! op]ation repeat$4 ,?is me?od 0 sl[ & exp5sive1 b gave good results4 ,ord9>y pit* c\ld n be us$ on acc\nt ( ! fumes1 :i* are p>ticul>ly objectionable 9 compress$ air4 ,! #fj pit* 0 slightly heat$ 9 ! op5 air be=e us+4 ,illu/ration3 ,,fig4 #c4 ,! sump & pump *amb] on ,tunnels ,c & ,d diff]$ f ! "o describ$ only 9 m9or details2 b1 be+ :olly con/ruct$ 9 rock1 pres5t$ few] difficulties & p]mitt$ a complete envelope ( wat]-pro(+ to be plac$ 9 ! top4 ,,concrete ,,l9+4 ,! plac+ ( concrete inside ! iron tube 0 done by an organization entirely sep>ate f ! tunnel+ =ce4 ,a mix+ plant 0 plac$ 9 ea* ( ! five %afts4 ,! /one & s& b9s dis*>g$ directly into mix]s bel[1 :i*1 9 turn1 dis*>g$ into /eel side-dump concrete c>s4 ,all concrete 0 plac$ 9 normal air4 ,! fir/ /ep1 aft] ! iron l9+ 0 scrap$ clean & wa%$ d[n & all leaks 7 /opp$1 0 ! plac+ ( biats1 m>k$ ,b on ,plate ,,lxxiv4 ,^! 7 made up ( a #f by #ab-;94 yell[ p9e timb]1 #ag ft4 long1 ) two %ort l5g?s ( ! same size splic$ to its ends by pieces ( #ab-;94 *annels1 #c ft4 #i 94 long1 clamp$ ^u ! sides4 ,^! biats 7 plac$ e #e ft4 along ! tunnel 9 r+s hav+ side keys4 ,next1 a floor1 #ac ft4 wide1 0 laid on ! biats & two tracks1 ( #cj-;94 gauge & #f-a_/b-;ft4 c5t]s1 7 laid ^u ! floor4 ,!re 7 ?ree /ages 9 ! concret+4 ,fig4 #b1 ,plate ,,lxxiv1 %[s ! concrete 9 place at ! end ( ! fir/1 & ,fig4 #c1 ,plate ,,lxxiv1 at ! end ( ! second /age4 ,! complete ar* above ! b5* walls 0 done 9 ! la/ op]ation4 ,two #c by #aj-;94 soldi]s 7,,ss 9 ,figs4 #a & #b1 ,plate ,,lxxiv7 7 fa/5$ to ea* biat & brac$ across by two horizontal & two diagonal braces4 ,to ea* pair ( soldi]s a floor template1 ,t1 0 !n nail$4 ,! =m = ! c5t] dra9 0 !n susp5d$ z %[n 9 ,fig4 #a1 ,plate ,,lxxiv4 ,?ree pieces ( %utt]+1 ,,fff1 #bj ft4 long1 7 !n nail$ to ! bottom ( ! soldi]s4 ,"o is all t w\ld h be5 ne$$ = ! fir/ concrete plac$1 b x 0 easi] to place !m at ?is /age ?an lat]1 :5 !re 0 less room4 ,?ree r\gh %utt]s 7 also nail$ to ! curv$ portion = ! floor template4 ,opposite ea* biat1 a bracket1 bb1 0 !n nail$1 :i* c>ries a set ( r\gh bo>ds :i* =m$ ! ris]s = ! duct /eps4 ,ev]y?+ 0 !n ready = concret+ except t1 :]e refuge ni*es occurr$1 a =m = ! portion ( ! ni*e bel[ ! seat 0 nail$ to ! %utt]+4 ,?is =m is %[n at ,r 9 ,fig4 #a1 ,plate ,,lxxiv4 ,illu/ration3 ,,plate ,,lxxiv ,! concrete 0 dump$ d[n on ea* side f side-dump c>s /&+ on ! track1 &1 fall+ betwe5 ! ris]s = ! duct /eps1 ran or 0 %ovel$ "u ! =ms & d[n into ! bottom4 ,! horizontal surface on ea* side ! c5t] dra9 0 smoo!d (f ) a %ovel4 ,! workm5 became v skillful at ?is1 & got a fairly smoo? surface4 ,?is concrete 0 usually plac$ 9 l5g?s ( #de or #fj ft4 ,aft] sett+ = ab\t #bd h\rs1 ! brackets1 bb1 7 remov$1 toge!r ) ! %utt]+ on ! /eps4 ,! triangul> pieces1 t 9 ,fig4 #a1 ,plate ,,lxxiv1 7 n remov$ until lat]4 ,in/ead1 a bo>d 0 laid ^u ?is l[] /ep on :i* ! duct lay]s c\ld "w4 ,?is & ! triangul> piece 7 n remov$ until j be=e ! b5* concrete 0 plac$4 ,?is 0 important1 z o!rwise ! bond betwe5 ! old & new concrete w\ld be mu* impair$ by dirt gr\nd into ! surface ( ! old concrete4 ,! ducts 7 !n laid1 z %[n 9 ,fig4 #b1 ,plate ,,lxxiv4 ,! rema9+ %utt]s = ! face ( ! b5* walls 7 !n plac$4 ,! rema9d] ( ! =ms = ! refuge ni*es1 ,,rr1 9 ,fig4 #a1 ,plate ,,lxxiv1 7 nail$ to ! %utt]s1 ! /eel beam ov] ! ni*e 0 laid 9 place1 ! =ms = ! ladd]s1 ,l 9 ,fig4 #b1 ,plate ,,lxxiv1 :i* occur e #be ft41 7 tack$ to ! %utt]s1 ! %utt]s & =ms 7 giv5 a coat ( creosote oil1 & !n all 0 ready = plac+ ! b5* concrete4 ,! specifications requir$ a #b-;94 mort> face to be plac$ on all expos$ surfaces & ! rema9d] to be smoo!d ) a tr[el & /raight-edge4 ,aft] ab\t #dh h\rs1 ! biats 7 block$ up on ! b5*1 & all =ms betwe5 ! b5* walls bel[ ! work+ floor 7 remov$4 ,! c5t]+ = ! ar* concrete consi/$ ( simple #e by #c-a_/b by #e_/af-;94 /eel-angle ar* ribs1 curv$ to ! prop] radius1 spac$ at #e-;ft4 int]vals4 ,ea* rib 0 made up ( two pieces splic$ toge!r at ! top4 ,two m5 easily h&l$ "o ( ^! pieces4 ,aft] splic+1 ! rib 0 support$ by f\r hang]-bolts fa/5$ to ! iron l9+ z %[n 9 ,fig4 #c1 ,plate ,,lxxiv4 ,9 ! e>ly "p ( ! "w1 two additional bolts 7 us$ ab\t half way up on ! side betwe5 ! upp] & l[] hang]-bolts4 ,x 0 soon f\nd t by plac+ ! /rut betwe5 ! tunnel l9+ & ! cr[n ( ! rib1 ^! hang]-bolts c\ld be disp5s$ )4 ,! lagg+ 0 ( #c-;94 dress$ yell[ p9e1 #ab 94 wide1 & 9 #ae-;ft4 l5g?s4 ,ea* piece _h ?ree saw cuts on ! back1 f end to end1 all[+ x to be b5t to ! curve ( ! ar*2 x 0 kept curv$ by an iron /rap screw$ to ! back4 ,! ar*es 7 put 91 ei!r 9 #ae1 #cj or #de-;ft4 l5g?s1 dep5d+ on :at 0 ready = concrete & :at c\ld be done 9 "o cont9u\s work+4 ,! rule 0 t :5 an ar* 0 begun1 ! "w mu/ n /op until x 0 f9i%$4 ,an ar* l5g? always end$ 9 ! middle ( a r+4 ,! lagg+ 0 plac$ to a height ( ab\t #f ft4 above ! b5* be=e any concret+ 0 done4 ,:5 ! concrete _h be5 br\ght up to t po9t1 lagg+ 0 add$1 "o piece at a "t1 j ahead ( ! concrete1 up to ! cr[n1 :]e a space ( ab\t #ah 94 0 left4 ,:5 ! lagg+ _h rea*$ ! upp] hang]-bolts1 !y 7 remov$1 :i* left only ! two bottom bolts fix$ 9 ! concrete4 ,mo/ ( ^! 7 unscrew$ f ! eye & sav$1 z t9 sleeves 7 plac$ ar\nd !m be=e concret+4 ,two ca/-iron eyes 7 lo/ = e #e ft4 ( tunnel4 ,to place ! key concrete1 a /age 0 set up 9 ! middle ( ! floor1 &1 beg9n+ at "o end1 ab\t #b ft4 ( block lagg+ 0 plac$4 ,ov] ?is1 concrete 0 pack$1 fill+ ! key z completely z possible4 ,?is 0 done p>tly by %ovel+ & us+ a %ort ramm]1 & p>tly by pack+ ) ! h&s by ! workm51 :o wore rubb] gloves = ! purpose4 ,ano!r #b ft4 ( lagg+ 0 !n plac$1 & ! op]ation 0 repeat$1 & ?us work+ backw>d1 foot by foot1 ! key 0 complet$4 ,?is is ! usual way ( key+ a concrete ar*1 b 9 ?is case ! difficulty 0 increas$ by ! flanges ( ! iron l9+4 ,x 0 practically impossible to fill all p>ts ( ! pockets =m$ by ^! flanges4 ,to meet ?is difficulty1 provision 0 made = gr\t+ any unfill$ space4 ,z ! concrete 0 be+ put 91 t9 pipes 7 plac$ ) _! tops ne>ly t\*+ ! iron l9+1 & _! bottoms re/+ on ! lagg+4 ,ea* pocket 0 int5d$ to h two ( ^! pipes1 "o to gr\t ?r\gh & ! o!r to act z a v5t = ! escape ( air4 ,ea* c5t] key r+ _h six pipes1 & ea* side key _h eight4 ,! bottoms ( ! pipes 7 held by a s+le nail driv5 half way into ! lagg+4 ,?is s]v$ to keep ! pipes 9 position & to locate !m aft] ! lagg+ 0 tak5 d[n4 ,! co/ ( labor 9 ! tunnels directly *>geable to concrete 0 #a4hj p] cu4 yd4 ,! top *>ges1 exclusive ( ! co/ ( mat]ials 7cem5t1 s&1 & /one71 am\nt$ to #c4ib4 ,,electric ,,conduits4 ,9 "o b5* wall ( ea* tunnel !re 7 fifte5 op5+s = p[] cables & 9 ! o!r1 betwe5 ! riv] %afts1 !re 7 =ty op5+s = telephone1 telegraph1 & signal cables4 ,ea/ ( ! ,long ,isl& %aft1 ! numb] ( ! latt] 0 r$uc$ to tw5ty-f\r4 ,! telephone ducts 7 all ( ! f\r-way type4 ,! specifications requir$ t ! p[] ducts %\ld h an op5+ ( n less ?an #c-a_/b 941 nor m ?an #c-g_/h 941 & t aft] lay+ !y %\ld pass a #d-;ft4 m&rel1 #c-c_/h 94 at ! lead+ end & #b-e_/h 94 at ! o!r4 ,! outside dim5sion 0 limit$ betwe5 #e & #e-c_/h 94 ,! op5+s ( ! f\r-way ducts 7 requir$ to be n less ?an #c-c_/h 941 nor m ?an #c-e_/h 941 & aft] lay+ to pass a #e-;ft4 m&rel1 #c-a_/d 94 at ! lead+ end & #b-a_/b 94 at ! o!r4 ,! outside dim5sions 7 limit$ betwe5 #i & #i-a_/b 94 ,all 7 to be laid 9 #a_/d-;94 b$s ( mort>4 ,! specifications 7 n def9ite z to ! %ape ( ! op5+1 b ^? us$ 7 squ>e ) corn]s r\nd$ to a radius ( #c_/h 94 ,! f\r-ways 7 #c ft4 long1 & ! s+les1 #ah 94 ,a /udy ( ! =ego+ dim5sions w %[ t ! work+ limits 7 n>r[4 ,su* n>r[ limits w\ld n pay = ! ord9>y conduit l9e 9 a /reet1 :]e !re is m room4 ,9 ! tunnel great] lib]ality meant ei!r r$uc+ ! numb] ( conduits or encroa*+ on ! /r5g? ( ! concrete tunnel l9+4 ,! small diff]5ce ( only #a_/h 94 9 ! size ( ! m&rel1 or a cle>ance ( only #a_/af 94 on ea* side1 no d\bt did increase ! co/ ( lay+ some:at1 ?\gh n z mu* z might at fir/ be suppos$4 ,all bottom c\rses 7 laid to a /r+1 9 practically p]fect l9e & grade1 & all jo9ts 7 te/$ ) m&rels :i* 7 9 all op5+s1 & pull$ =w>d z ea* piece ( conduit 0 laid4 ,z ! workm5 became skillful1 ! progress 0 excell5t4 ,all co/s ( labor 9 ! tunnel *>geable to duct lay+ am\nt$ to #j4jci p] ft4 ( duct2 top *>ges br\ght ?is up to #j4jhc4 ,! s]i\s problem 0 to gu>d aga9/ gr\t & mort> runn+ into ! duct op5+ ?r\gh ! jo9ts f ! concrete1 :i* 0 a r wet mixture4 ,ea* jo9t 0 wrapp$1 :5 laid1 ) canvas1 weigh+ #aj oz4 p] sq4 yd41 dipp$ 9 cem5t gr\t imm$iately be=e us+4 ,^! wraps 7 #f 94 wide1 & 7 cut long en\gh to g ar\nd ! lap ab\t ! middle ( ! duct4 ,z soon z all ! ducts 7 laid1 ! entire bank 0 pla/]$ ov] ) fairly /iff mort>1 :i*1 :5 prop]ly done1 clos$ all op5+s4 ,! pla/]+ 0 n requir$ by ! specifications1 b 0 f\nd by ! contractor to result 9 a sav+ 9 ultimate co/4 ,! concrete on ! two sides ( ! bank ( ducts 0 bond$ toge!r by #b by #a_/h-;94 /eel bonds betwe5 ! ducts1 laid across 9 horizontal jo9ts4 ,bo? ends 7 split into two pieces1 #a 94 long1 "o ( :i* 0 turn$ up & ! o!r d[n4 ,^! bonds project$ #a-a_/b 94 into ! concrete on ei!r side4 ,:]e ! bond came opposite ! ris]s ( ! duct /ep1 aga9/ :i* ! ducts 7 laid1 recesses 7 provid$ = ! project+ bond4 ,?is 0 done by nail+ to ! r\gh %utt]s = ! /eps a =m :i* :5 remov$ left a dove-tail$ v]tical groove4 ,?is =m 0 made 9 two pieces1 "o tap]+ inw>d & ! o!r ) m tap] outw>d4 ,z ! bonds 7 plac$1 ^! grooves 7 fill$ ) mort>4 ,! ducts usually receiv$ _! f9al rodd+ ) ! specification m&rel a mon? or m aft] !y 7 laid1 aft] :i* all op5+s into splic+ *amb]s 7 /opp$ by wood5 plugs1 #h 94 long tap]+ f #c-c_/d 94 at "o end to #b-c_/d 94 at ! o!r end1 & %ap$ to fit ! op5+ tightly4 ,at fir/ ! plugs 7 p>aff9$1 to keep !m f swell+ & break+ ! ducts1 b 7 n successful1 z ! p>aff9 lubricat$ !m s t !y w\ld n /ay 9 place4 ,!y 7 exp5sive1 & !re 0 "s swell+ 9 ! be/ t 7 obta9$4 ,a bett] plug 0 made by us+ no p>aff91 b by mak+ six saw cuts1 ?ree horizontal & ?ree v]tical1 9 ! l>g] end1 cutt+ to )9 ab\t #b 94 ( ! small] end4 ,! swell+ ( ! wood 0 !n tak5 up by ! saw cuts & ! spr+ ( ! wood4 ,! splic+ *amb]s are at #djj-;ft4 int]vals4 ,!y are #f ft4 long1 #d ft4 #i 94 high1 ) a wid? v>y+ f #c ft4 #b 94 at ! top to #a ft4 #b 94 at ! bottom4