an autobiography-第97章

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normous　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。　

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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　the　most　gentle　pressure；　or　to　possess　the　power　of　compressing　to　upwards　of　twenty　thousand　tons；　the　only　limit　to　its　power　being　in　the　materials　employed　in　its　construction。

The　principle　of　this　enormously　powerful　compressing　machine　is　similar　to　that　of　the　Hydraulic　Press；　the　difference　consisting　principally　in　the　substitution　of　what　I　term　a　Hydraulic　Mattress　in　place　of　the　cylinder　and　ram　of　the　ordinary　hydraulic　press。　The　Hydraulic　Mattress　consists　of　a　square　or　circular　water…tight　vessel　or　flat　bag　formed　of　1/2…inch　thick　iron　or　steel　plates　securely　riveted　together；　its　dimensions　being；　say　15　feet　square　by　3　feet　deep；　and　having　semicircular　sides；　which　form　enables　the　upper　flat　part　of　the　Mattress　to　rise　say　to　the　extent　of　6　inches；　without　any　injury　to　the　riveted　joints；　as　such　a　rise　or　alteration　of　the　normal　form　of　the　semicircular　sides　would　be　perfectly　harmless；　and　not　exceed　their　capability　of　returning　to　their　normal　curve　when　the　6…inch　rise　was　no　longer　necessary；　and　the　elevating　pressure　removed。

＇image＇

The　action　of　this　gigantic　press　is　as　follows。　　The　Mattress　A　A　having　been　filled　with　water；　an　additional　quantity　is　supplied　by　a　force　pump；　capable　of　forcing　in　water　with　a　pressure　of　one　ton　to　the　square　inch；　thus　acting　on　an　available　surface　of　at　least　144　square　feet　surfacenamely；　that　of　the　upper　flat　surface　of　the　Mattress。　　It　will　be　forced　up　by　no　less　a　pressure　than　twenty　thousand　tons；　and　transfer　that　enormous　pressure　to　any　article　that　is　placed　between　the　rising　table　of　the　press　and　the　upper　table。　When　any　object　less　thick　than　the　normal　space　is　required　to　receive　the　pressure；　the　spare　space　must　be　filled　with　a　suitable　set　of　iron　flat　blocks；　so　as　to　subject　the　article　to　be　pressed　to　the　requisite　power。

As　before　stated；　there　may　be　many　processes　in　the　manufacturing　arts　in　which　such　an　enormous　pressure　may　be　useful；　and　this　can　be　accomplished　with　perfect　ease　and　certainty。　　I　trust　that　this　account　of　the　principles　and　construction　of　s