an autobiography-第86节

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1838。　Invention　of　the　Steam　Ram

My　invention　was　made　at　this　early　date；　long　before　the　attack　by　the　steam…ram　Merrimac　upon　the　Cumberland；　and　other　ships；　in　Hampton　Roads；　United　States。　　I　brought　my　plans　and　drawings　under　the　notice　of　the　Admiralty　in　1845；　but　nothing　was　done　for　many　years。　　Much　had　been　accomplished　in　rendering　our　ships　shot…proof　by　the　application　of　iron　plates；　but　it　appeared　to　me　that　not　one　of　them　could　exist　above　water　after　receiving　on　its　side　a　single　blow　from　an　iron…plated　steam…ram　of　2000　tons。　　I　said；　in　a　letter　to　the　Times；　〃As　the　grand　object　of　naval　warfare　is　the　destruction　by　the　most　speedy　mode　of　the　ships　of　the　enemy；　why　should　we　continue　to　attempt　to　attain　this　object　by　making　small　holes　in　the　hull　of　the　enemy　when；　by　one　single　masterly　crashing　blow　from　a　steam　ram；　we　can　crush　in　the　side　of　any　armour…plated　ship；　and　let　the　water　rush　in　through　a　hole；　'not　perhaps　as　wide　as　a　church　door　or　as　deep　as　a　well；　but　'twill　serve'；　and　be　certain　to　send　her　below　water　in　a　few　minutes。*　　＇footnote。。。　In　these　days　of　armour…clad　warships；　when　plates　of　enormous　thickness　are　relied　on　as　invulnerable；　our　Naval　Constructors　appear　to　forget　that　the　actual　structural　strength　of　such　ships　depends　on　the　backing　of　the　plates；　which；　be　it　ever　so　thick；　would　yield　to　the　cramming　blow　of　a　moderate…sized　Ram。　　。。。＇

I　published　my　description　of　the　steam　ram　and　its　apparatus　in　the　Times　　of　January　1853；　and　again　addressed　the　Editor　on　the　subject　in　April　1862。　　General　Sir　John　Burgoyne　took　up　the　subject；　and　addressed　me　in　the　note　at　the　foot　of　this　page。*　　＇footnote。。。　The　following　is　the　letter　of　General　Sir　John　Burgoyne：

WAR　OFFICE；　PALL　MALL；　LONDON；　8th　April　1862。

〃General　Sir　John　Burgoyne　presents　his　compliments　to　Mr。　Nasmyth；　and　was　much　pleased　to　find；　by　Mr。　Nasmyth's　letter　in　the　Times　of　this　day；　certain　impressions　that　he　has　held　for　some　time　confirmed　by　so　good　an　authority。　　〃A　difficulty　seems　to　be　anticipated　by　many　that　a　steamer　used　as　a　ram　with　high　velocity；　if　impelled　upon　a　heavy　ship；　would；　by　the　revulsion　of　the　sudden　shock；　be　liable　to　have　much　of　her　gear　thrown　entirely　out　of　order；　parts　displaced；　and　perhaps　the　boilers　burst。　　Some　judgment；　however；　may　be　formed　on　this　point　by　a　knowledge　of　whether　such　circumstances　have　occurred　on　ships　suddenly　grounding；　and　even　so；　it　may　be　a　question　whether　so　great　a　velocity　is　necessary。　　〃An　accident　occurred　some　twenty　years　ago；　within　Sir　John　Burgoyne's　immediate　cognisance；　that　has　led　him　particularly　to　consider　the　great　power　of　a　ship　acting　as　a　ram。　　A　somewhat　heavy　steamer　went；　by　accident　or　mismanagement；　end　on　to　a　very　substantial　wharf　wall　in　Kingstown　Harbour；　Dublin　Bay。　Though　the　force　of　the　blow　was　greatly　checked　through　the　measures　taken　for　that　purpose；　and　indeed　so　much　so　that　the　vessel　itself　suffered　no　very　material　injury；　yet　several　of　the　massive　granite　stones　of　the　facing　were　driven　some　inches　in；　showing　the　enormous　force　used　upon　them。　　〃Superior　speed　will　be　very　essential　to　the　successful　action　of　the　ram；　but　by　the　above　circumstance　we　may　assume　that　even　a　moderate　speed　would　enable　great　effects　to　be　produced；　at　least　on　any　comparatively　weak　point　of　even　ironclad　ships；　such　as　the　rudder。〃　　。。。＇

In　June　1870；　I　received　a　letter　from　Sir　E。　J。　Reed；　containing　the　following　extracts：　〃I　was　aware　previously　that　plans　had　been　proposed　for　constructing　unarmoured　steam　rams；　but　I　was　not　acquainted　with　the　fact　that　you　had　put　forward　so　well…maturerd　a　scheme　at　so　early　a　date；　and　it　has　given　me　much　pleasure　to　find　that　such　is　the　case。　　It　has　been　a　cause　both　of　pleasure　and　surprise　to　me　to　find　that　so　long　ago　you　incorporated　into　a　design　almost　all　the　features　which　we　now　regard　as　essential　to　ramming　efficiencytwin　screws　and　moderate　dimensions　for　handiness；　numerous　water…tight　divisions　for　safety；　and　special　strengthenings　at　the　bow。　　Facts　such　as　these　deserve　to　be　put　on　record。。。。　Meanwhile　accept　my　congratulations　on　the　great　skill　and　foresight　which　your　ram…design　displays。〃

Collisions　at　sea　unhappily　afford　ample　evidence　of　the　fatal　efficiency　of　the　ramming　principle。　　Even　ironclad　ships　have　not　been　able　to　withstand　the　destructive　effect。　　The　Vanguard　and　the　Kurfurst　　now　lie　at　the　bottom　of　the　sea　in　consequence　of　an　accidental　〃end…on〃　ram　from　a　heavy　ship　going　at　a　moderate　velocity。　　High　speed　in　a　Steam　Ram　is　only　desirable　when　the　attempt　is　made　to　overtake　an　enemy's　ship；　but　not　necessary　for　doing　its　destructive　work。　A　crash　on　the　thick　plates　of　the　strongest　Ironclad；　from　a　Ram　of　2000　tons　at　the　speed　of　four　miles　an　hour；　would　drive　them　inwards　with　the　most　fatal　results。


1839。　Invention　of　the　Steam　Hammer；　in　its　general　principles　and　　　　　　　details。

Described　in　text；　p。　　231。


1839。　　Invention　of　the　Floating　Mortar　or　Torpedo　Ram。

For　particulars　and　details；　see　Report　of　Torpedo　Committee。


1839。　A　Double…faced　Wedge…shaped　Sluice…Valve　for　Main　Street　　　　　　　Water…pipes。

The　late　Mr。　Wicksteed；　engineer　of　the　East　London　Water　Company；　having　stated　to　me　the　inconvenience　which　had　been　experienced　from　the　defects　in　respect　of　water…tightness；　as　well　as　the　difficulty　of　opening　and　closing　the　valves　of　the　main　water…pipes　in　the　streets；　I　turned　my　attention　to　the　subject。　　The　result　was　my　contrivance　of　a　double…faced　wedge…shaped　sluice…valve；　which　combined　the　desirable　property　of　perfect　water…tightness　with　ease　of　opening　and　closing　the　valve。

This　was　effected　by　a　screw　which　raised　the　valve　from　its　bearings　at　the　first　partial　turn　of　the　screw；　after　which　there　was　no　further　resistance　or　friction；　except　the　trifling　friction　of　the　screw　in　its　nut　on　the　upper　part　of　the　sluice…valve。　　When　screwed　down　again；　it　closed　simultaneously　the　end　of　the　entrance　pipe　and　that　of　the　exit　pipe　attached　to　the　valve　case　in　the　most　effective　manner。　

＇image＇　

Mr。　Wicksteed　was　so　much　pleased　with　the　simplicity　and　efficiency　of　this　valve　that　he　had　it　applied　to　all　the　main　pipes　of　his　Company。　When　its　advantages　became　known；　I　received　many　orders　from　other　water　companies；　and　the　valves　have　since　come　into　general　use。　The　prefixed　figure　will　convey　a　clear　idea　of　the　construction。　The　wedge　form　of　the　double…faced　valve　is　conspicuous　as　the　characteristic　feature　of　the　arrangement。*　　＇footnote。。。　At　a　meeting　of　the　Institution　of　Civil　Engineers；　May　23；　1883；　when　various　papers　were　read　on　Waterworks；　Mr。　H。　I。　Marten　observed　in　the　course　of　the　discussion：　〃It　has　been　stated　in　Mr。　Gamble's　paper　（on　the　waterworks　of　Port　Elizabeth）　that　the　sluice　valves　are　of　the　usual　pattern。　　The　usual　patterns　of　the　present　day　are　in　wonderful　advance　of　those　of　thirty　or　forty　years　since。　　The　great　improvement　originated　with　the　introduction　of　'the　double…faced　sluice…cock。'　This　sluice…cock；　which　had　now　superseded　every　other　description；　was　the　creation　of　Mr。　James　Nasmyth's　inventive　genius。　Mr。　Marten　said　he　well　remembered　the　first　reception　of　this　useful　invention；　as　he　happened　at　that　time　to　be　a　pupil　of　Mr。　Thomas　Wicksteed。　　He　was　present　when　Mr。　Wicksteed　explained　to　Mr。　Nasmyth　the　want　he　had　experienced　of　a　sluice…cock　for　Waterworks　purposes；　which　should　shut　and　remain　perfectly　tight　against　a　pressure　coming　from　either　side。　　Mr。　Marten　had　a　lively　recollection　of　the　instantaneous　rapidity　with　which　Mr。　Nasmyth　not　only　grasped　but　provided　for　the　requirement；　so　that　almost　by　the　time　Mr。　Wicksteed　had　completed　the　statement　of　his　want；　Mr。　Nasmyth　had　drawn　upon　the　back　of　an　old　letter　a　rough　sketch　of　the　first　double…faced　sluice…cock；　and　in　less　than　an　hour　had　converted　this　rough　sketch　into　a　full…sized　working　drawing；　in　the　preparation　of　which　it　fell　to　Mr。　Marten's　lot　to　have　the　honour　to　assist。　　In　his　'Autobiography'　Mr。　Nasmyth　referred　to　the　conversation　with　Mr。　Wicksteed；　and　introduced　a　print　of　the　drawing　made　upon　the　occasion。　　The　invention　has　been　of　the　greatest　use　to　the　Waterworks　Engineer；　especially　in　connection　with　the　constant　supply　system；　in　which　it　frequently　happened　that　the　pressure　was　sometimes　against　one　face　of　the　sluice…cock；　and　sometimes　against　the　other。〃　See　Proceedings　and　Discussions　of　the　Institution　of　Civil　Engineers；　1883；　pp。　88；　89。　　。。。＇


1839。　A　Hydraulic　Mattress　Press；　capable　of　exerting　a　pressure　of　　　　　　　Twenty　thousand　tons。

Being　under　the　impression　that　there　are　many　processes　in　the　manufacturing　arts；　in　which　a　perfectly　controllable　compressing　power　of　vast　potency　might　be　serviceable；　I　many　years　ago　prepared　a　design　of　an　apparatus　of　a　very　simple　and　easily　executed　kind；　which　would　supply　such　a　desideratum。　　It　was　possessed　of　a　range　of　compressing　or　squeezing　　power；　which　far　surpassed　anything　of　the　kind　that　had　been　invented。　　As　above　said；　it　was　perfectly　controllable；　so　as　either　to　yield　t