an autobiography-第50部分

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orge　work。　　I　gave　them　every　opportunity　for　observing　its　action。　They　were　much　pleased；　and　I　may　add　astonished；　at　its　range；　power；　and　docility。

Besides　showing　them　my　own　steam　hammer；　I　took　the　deputation　to　the　extensive　works　of　Messrs。　　Rushton　and　Eckersley；　where　they　saw　one　of　my　five…ton　hammer…block　steam　hammers　in　full　action。　It　was　hammering　out　some　wrought…iron　forgings　of　the　largest　class；　as　well　as　working　upon　smaller　forgings。　　By　exhibiting　the　wide　range　of　power　of　the　steam　hammer；　these　gentlemen　were　entirely　satisfied　of　its　fitness　for　all　classes　of　forgings　for　the　naval　service。　They　reported　to　the　Admiralty　accordingly；　and　in　a　few　days　we　received　an　official　letter；　with　an　order　for　a　steam　hammer　having　a　50　cwt。　　hammer…block；　together　with　the　appropriate　boiler；　crane；　and　forge　furnace；　so　as　to　equip　a　complete　forge　shop　at　Devonport　Dockyard。　　This　was　my　first　order　from　the　Government　for　a　steam　hammer。

When　everything　was　ready；　I　set　out　for　Devonport　to　see　the　hammer　and　the　other　portions　of　the　machinery　carefully　erected。　In　about　a　fortnight　it　was　ready　for　its　first　stroke。　　As　good　luck　would　have　it；　the　Lords　of　the　Admiralty　were　making　their　annual　visit　of　inspection　to　the　dockyard　that　day。　　They　arrived　too　late　in　the　afternoon　for　a　general　inspection　of　the　establishment；　but　they　asked　the　superintending　admiral　if　there　was　anything　of　importance　which　they　might　see　before　the　day　closed。　　The　admiral　told　them　that　the　most　interesting　novelty　in　the　dockyard　was　the　starting　of　Nasmyth's　steam　hammer。　　〃Very　well；　they　said；　〃let　us　go　and　see　that〃。

I　was　there；　with　the　two　mechanics　I　had　brought　with　me　from　Patricroft　to　erect　the　steam　hammer。　　I　took　share　and　share　alike　in　the　work。　　The　Lords　were　introduced　to　me；　and　I　proceeded　to　show　them　the　hammer。　　I　passed　it　through　its　paces。　　I　made　it　break　an　eggshell　in　a　wine…glass　without　injuring　the　glass。　　It　was　as　neatly　effected　by　the　two…and…a…half　ton　hammer　as　if　it　had　been　done　by　an　egg…spoon。　　Then　I　had　a　great　mass　of　white…hot　iron　swung　out　of　the　furnace　by　a　crane　and　placed　upon　the　anvil　block。　　Down　came　the　hammer　on　it　with　ponderous　blows。　　My　Lords　scattered　to　the　extremities　of　the　workshop；　for　the　splashes　and　sparks　of　hot　metal　flew　about。　　I　went　on　with　the　hurtling　blows　of　the　hammer；　and　kneaded　the　mass　of　iron　as　if　it　had　been　clay　into　its　devised　forms。

After　finishing　off　the　forging；　my　Lords　gathered　round　the　hammer　again；　when　I　explained　to　them　the　rationale　of　its　working；　and　the　details　of　its　construction。　　They　were　greatly　interested；　especially　Mr。　Sidney　Herbert　（afterwards　Lord　Herbert　of　Lea）；　then　Secretary　to　the　Admiralty；　and　Sir　George　Cockburn；　a　fine　specimen　of　the　old　admiral。　　Indeed；　all　the　members　of　the　Board　were　more　or　less　remarkable　men。　　They　honoured　me　with　their　careful　attention；　and　expressed　their　admiration　at　the　hammer's　wonderful　range　of　power　and　delicacy　of　touch；　in　this　new　application　of　the　force　of　steam。

The　afternoon　was　a　most　important　one　for　me　in　more　ways　than　one；　although　I　cannot　venture　to　trouble　my　readers　with　the　details。　It　was　followed；　however；　by　an　order　to　supply　all　the　Royal　Dockyard　forge　departments　with　a　complete　equipment　of　steam　hammers；　and　all　the　requisite　accessories。　　These　were　supplied　in　due　time；　and　gave　in　every　case　the　highest　satisfaction。　　The　forgings　were　found　to　be　greatly　better；　and　almost　absurdly　cheaper　than　those　done　by　the　old　bit　by　bit　building…up　process。　　The　danger　of　flaws　was　entirely　done　away　with；　and；　in　the　case　of　anchors；　this　was　a　consideration　of　life　and　death　to　the　seamen；　who　depend　for　their　safety　upon　the　soundness　of　the　forgings。

Besides　my　introduction　to　that　admirable　man；　Mr。　Sidney　Herbert；　I　had　the　happiness　of　being　introduced　to　Captain　Brandreth；　Director　of　Naval　Works。　　The　whole　of　the　buildings　on　shore；　including　the　dockyards；　were　under　his　control。　　One　of　the　most　important　affairs　that　the　Lords　of　the　Admiralty　had　to　attend　to　on　their　visit　to　Devonport　was　to　conclude　the　contract　for　constructing　the　great　docks　at　Keyham。　　This　was　a　large　extension　of　the　Devonport　Docks；　intended　for　the　accommodation　of　the　great　steamships　of　the　Royal　Navy；　as　well　as　for　an　increase　of　the　graving　docks　and　workshops　for　their　repair。　　An　immense　portion　of　the　shore　of　the　Hamoaze　had　to　be　walled　in　so　as　to　exclude　the　tide　and　enable　the　space　to　be　utilised　for　the　above　purposes。　　To　effect　this　a　vast　amount　of　pile…driving　was　rendered　necessary；　in　order　to　form　a　firm　foundation　for　the　great　outer　dock　wall；　about　a　mile　and　a　quarter　in　length。

Messrs。　Baker　and　Sons　were　the　contractors　for　this　work。　They　were　present　at　the　first　start　of　my　steam　hammer　at　Devonport。　They　were；　like　the　others；　much　impressed　by　its　vast　power　and　manageableness。　　They　had　an　interview　with　me　as　to　its　applicability　for　driving　piles　for　the　immense　dock；　this　being　an　important　part　of　their　contract。　　Happily；　I　had　already　given　some　attention　to　this　application　of　the　powers　of　the　steam　hammer。　　In　fact；　I　had　secured　a　patent　for　it。　　I　had　the　drawings　for　the　steam　hammer　pile…driving　machine　with　me。　　I　submitted　them　to　Mr。　Baker；　and　he　saw　its　importance　in　a　moment。　　〃That；〃　he　'said；　〃is　the　very　thing　that　I　want　to　enable　me　to　complete　my　contract　satisfactorily。〃　　Thousands　of　enormous　piles　had　to　be　driven　down　into　the　deep　silt　of　the　Shore；　and　to　have　driven　them　down　by　the　old　system　of　pile…driving　would　have　occupied　a　long　time；　and　would　also　have　been　very　expensive。

The　drawings　were　of　course　submitted　to　Captain　Brandreth。　He　was　delighted　with　my　design。　　The　steam　pile…driver　would　be；　in　his　opinion；　the　prime　agent　for　effecting　the　commencement　of　the　great　work　originated　by　himself。　　At　first　the　feat　of　damming　out　such　a　high　tide　as　that　of　the　Hamoaze　seemed　very　doubtful；　because　the　stiff　slate　silt　was　a　treacherous　and　difficult　material　to　penetrate。　　But　now；　he　thought；　the　driving　would　be　rendered　comparatively　easy。　　With　Captain　Brandreth's　consent　the　contractors　ordered　of　me　two　of　my　steam　hammer　pile…drivers。　　They　were　to　be　capable　of　driving　18…inch　square　piles　of　70　feet　in　length　into　the　silt　of　the　Hamoaze。

＇Image＇　　Space　to　be　enclosed　at　the　Hamoaze

This　first　order　for　my　pile…driver　was　a　source　of　great　pleasure　to　me。　I　had　long　contemplated　this　application　of　the　power　of　the　steam　hammer。　　The　machine　had　long　been　in　full　action　in　my　〃mind's　eye；〃　and　now　I　was　to　see　it　in　actual　reality。　　I　wrote　down　to　my　partner　by　that　night's　post　informing　him　of　the　happy　circumstance。　The　order　was　for　two　grand　steam　hammer　pile…drivers；　each　with　four…ton　hammer…blocks。The　wrought…iron　guide　case　and　the　steam　cylinder　were　to　weigh　in　all　seven　tons。　　All　this　weight　was　to　rest　on　the　shoulders　of　the　pile。　　The　blows　were　to　be　about　eighty　in　the　minute。　　This；　I　thought；　would　prove　thoroughly　effective　in　rapidly　driving　the　piles　down　into　the　earth。

I　have　said　that　the　steam　pile…driver　was　in　my　mind's　eye　long　before　I　saw　it　in　action。　　It　is　one　of　the　most　delightful　results　of　the　possession　of　the　constructive　faculty；　that　one　can　build　up　in　the　mind　mechanical　structures　and　set　them　to　work　in　imagination；　and　observe　beforehand　the　various　details　performing　their　respective　functions；　as　if　they　were　in　absolute　material　form　and　action。　Unless　this　happy　faculty　exists　ab　initio　in　the　brain　of　the　mechanical　engineer；　he　will　have　a　hard　and　disappointing　life　before　him。　　It　is　the　early　cultivation　of　the　imagination　which　gives　the　right　flexibility　to　the　thinking　faculties。　　Thus　business；　commerce；　and　mechanics　are　all　the　better　for　a　little　healthy　imagination。

So　soon　as　I　had　returned　home；　I　set　to　work　and　prepared　the　working　drawings　of　the　steam　pile…drivers。　　They　were　soon　completed；　conveyed　to　Devonport；　and　erected　on　the　spot　where　they　were　to　be　used。　They　were　ready　on　the　3d　of　July　1845。　　Some　preliminary　pile…driving　had　been　done　in　the　usual　way；　in　order　to　make　a　stage　or　elevated　way　for　my　pile…driver　to　travel　along　the　space　where　the　permanent　piles　were　to　be　driven。　　I　arranged　my　machines　so　that　they　might　travel　by　their　own　locomotive　powers　along　the　whole　length　of　the　coffer　dam；　and　also　that　they　should　hoist　up　the　great　logs　of　Baltic　timber　which　formed　the　Piles　into　their　proper　places　before　being　driven。

The　entire　apparatus　of　the　machine　was　erected　on　a　strong　timber　platform；　and　was　placed　on　wheels；　so　that　it　might　move　along　the　rails　laid　down　upon　the　timber　way。　　The　same　boiler　that　supplied　the　steam　hammer　part　of　the　apparatus　served　to　work　the　small　steam…engine　fixed　to　the　platform　for　its　locomotion；　and　also　to　perform　the　duty　of　rearing　the　next　pile　which　had　to　be　driven。　　The　steam　was　conveyed　to　the　hammer　cylinder　by　the　jointed　pipe　seen　in　the　annexed　engraving。　　The　pipe　accommodated　itself　to　any　elevation　or　descent　of　the　hammer。　　The　whole　weight　of　the　cylinder；　hammer…block；　and　guide　box；　supported　by　the　shoulders　of　the　pile；　amounting　to　seven　tons　in　all；　rested　upon　the　shoulders　of　the　pile　as　a　〃persuader；〃　and　the　eighty　blows　per　minute　of　the　four…ton　hammer　came　down　with　tremendous　energy　upon　the　top　of　the　pile　head。　　No　soil；　that　piles　could　penetrate；　could　resist　such　effective　agencies。

＇Image＇　　Diagram　of　the　Steam　Pile…Driver

Explanation　of　the　Diagram　of　the　Steam　Pile…Driver。The　chief　feature　of　novelty　of　this　pile…driving　machine　consists　in　the　employment　of　the　direct　action　of　the　Steam　Hammer　as　the　blow　giving　agent；　and　also　in　the　manner　in　which　the　dead　weight　of　the　entire　apparatus；　consisting　of　the　hammer…block　C；　the　steam　cylinder　A；　and　its　guide…case　B；　is　employed　to　importantly　aid　the　effect　of　the　rapid　and　energetic　blows　of　the　steam　hammer。　　These　ponderous　parts　rest　on　the　shoulders　of　the　pile　H　all　the　while　it　is　being　driven；　the　pile　in　this　respect　being　the　only　support　of　the　apparatus　A　B　C。　So　that；　besides　t