an autobiography-第70章

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With　the　desire　of　rendering　the　valuable　services　of　the　Planing　Machine　applicable　to　the　smallest　detail　parts　of　machine　manufacture；　I　designed　a　simple　and　compact　modification　of　it；　such　as　should　enable　any　attentive　lad　to　execute　all　the　detail　parts　of　the　machines　in　so　unerring　and　perfect　a　manner　as　not　only　to　rival　the　hand　work　of　the　most　skilful　mechanic；　but　also　at　such　a　reduced　cost　as　to　place　the　most　active　hand　workman　far　into　the　background。　The　contrivance　I　refer　to　is　usually　known　as　〃Nasmyth's　Steam　Arm。〃　None　but　those　who　have　had　ample　opportunities　of　watching　the　process　of　executing　the　detail　parts　of　machines；　can　form　a　correct　idea　of　the　great　amount　of　time　that　is　practically　wasted　and　unproductive；　even　when　highly…skilled　and　careful　workmen　are　employed。　　They　have　so　frequently　to　stop　working；　in　order　to　examine　the　work　in　hand；　to　use　the　straight　edge；　the　square；　or　the　calipers；　to　ascertain　whether　they　are　〃working　correctly。〃　　During　that　interval；　the　work　is　making　no　progress：　and　the　loss　of　time　on　this　account　is　not　less　than　one…sixth　of　the　working　hours；　and　sometimes　much　more；　though　all　this　lost　time　is　fully　paid　for　in　wages。

＇Image＇　　Apparatus　for　enabling　the　machine　to　execute　segmented　work

But　by　the　employment　of　such　a　machine　as　I　describe；　even　when　placed　under　the　superintendence　of　well…selected　intelligent　lads；　in　whom　the　faculty　of　good　sight　and　nicety　of　handling　is　naturally　in　a　high　state　of　perfection；　any　deficiency　in　their　physical　strength　is　amply　compensated　by　these　self…acting　machines。　　The　factory　engine　supplies　the　labour　or　the　element　of　Force；　while　the　machines　perform　their　work　with　practical　perfection。　　The　details　of　machinery　are　thus　turned　out　with　geometrical　accuracy；　and　are　in　the　highest　sense　fitted　to　perform　their　intended　purposes。


1837。　Solar　Ray　Origin　of　the　form　of　the　Egyptian　Pyramids；　Obelisks；　　　　　　　etc。

This　will　be　found　described　summarily　in　the　next　and　final　chapter。


1837。　Method　of　reversing　the　action　of　Slide　Lathes。

In　the　employment　of　Slide　Turning　Lathes；　it　is　of　great　advantage　to　be　able　to　reverse　the　motion　of　the　Slide　so　as　to　enable　the　turning　tool　to　cut　towards　the　Head　of　the　Lathe　or　away　from　it；　and　also　to　be　able　to　arrest　the　motion　of　the　Slide　altogether；　while　all　the　other　functions　of　the　lathe　are　continued　in　action。　　All　these　objects　are　attained　by　the　simple　contrivance　represented　in　the　annexed　illustration。

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It　consists　of　a　lever　E；　moving　on　a　stud…pin　S；　attached　to　the　back　of　the　head　stock　of　the　lathe　T。　　This　lever　carries　two　wheels　of　equal　diameter　marked　B　and　G。　　These　wheels　can　pitch　into　a　corresponding　wheel　A；　fixed　on　the　back　end　of　the　lay　spindle。　When　the　handle　of　the　lever　E　is　depressed　（as　seen　in　the　drawing）　the　wheel　B　is　in　gear　with　wheel　A。　　while　C　is　in　gear　with　the　slidescrew　wheel　D；　and　so　moves　the　slide　（say　from　the　Head　Stock　of　the　lathe）。　　On　the　other　hand；　when　the　lever　E　is　elevated　in　position　E〃；　wheel　B　is　taken　out　of　gear　with　A；　while　G　is　put　in　gear　with　A；　and　B　is　put　in　gear　with　D；　and　thus　the　Slide　is　caused　to　move　towards　the　Head　Stock　of　the　lathe。　　Again；　where　it　is　desired　to　arrest　the　motion　of　the　Slide　altogether；　or　for　a　time；　as　occasion　may　require；　the　lever　handle　is　put　into　the　intermediate　position　E'；　which　entirely　severs　the　communication　between　A　and　D；　and　so　arrests　the　motion　of　the　slide。　　This　simple　contrivance　effectually　served　all　its　purposes；　and　was　adopted　by　many　machine　tool…makers　and　engineers。


1838。　Self…adjusting　Bearings　for　the　Shafts　of　Machinery

A　frequent　cause　of　undue　friction　and　heating　of　rapidly　rotating　machinery　arises　from　some　inaccuracy　or　want　of　due　parallelism　between　the　rotating　shaft　or　spindle　and　its　bearing。　　This　is　occasioned　in　most　cases　by　some　accidental　change　in　the　level　of　the　supports　of　the　bearings。　　Many　of　the　bearings　are　situated　in　dark　places；　and　cannot　be　seen。　　There　are　others　that　are　difficult　of　accessas　in　the　case　of　bearings　of　screw…propeller　shafts。　Serious　mischief　may　result　before　the　heating　of　the　bearing　proclaims　its　dangerous　condition。　　In　some　cases　the　timber　work　is　set　on　fire；　which　may　result　in　serious　consequences。

In　order　to　remove　the　cause　of　such　serious　mischief；　I　designed　an　arrangement　of　bearing；　which　enabled　it；　and　the　shaft　working　in　it；　to　mutually　accommodate　themselves　to　each　other　under　all　circumstances；　and　thus　to　avoid　the　danger　of　a　want　of　due　and　mutual　parallelism　in　their　respective　axes。　　This　arrangement　consisted　in　giving　to　the　exterior　of　the　bearing　a　spherical　form；　so　as；　within　moderate　limits；　to　allow　it　to　accommodate　itself　to　any　such　changes　in　regard　to　mutual　parallelism；　as　above　referred　to。　　In　other　cases；　I　employed　what　I　may　call　Rocking　centres；　on　which　the　Pedestal　or　〃Plumber　Block〃　rested；　and　thus　supplied　a　self…adjusting　means　for　obviating　the　evils　resulting　from　any　accidental　change　in　the　proper　relative　position　of　the　shaft　and　its　bearing。　　In　all　cases　in　which　I　introduced　this　arrangement；　the　results　were　most　satisfactory。

In　the　case　of　the　bearings　of　Blowing　Fans；　in　which　the　rate　of　rotation　is　naturally　excessive；　a　spherical　resting…place　for　the　bearings　enabled　them　to　keep　perfectly　cool　at　the　highest　speed。　This　was　also　the　case　in　the　driving　apparatus　for　machine　tools；　which　is　generally　fixed　at　a　considerable　height　above　the　machine。　These　spherical　or　self…adjusting　bearings　were　found　of　great　service。　The　apparatus；　being　generally　out　of　convenient　reach；　is　apt　to　get　out　of　order　unless　duly　attended　to。　　But；　whether　or　not；　the　saving　of　friction　is　in　itself　a　reason　for　the　adoption　of　such　bearings。　This　may　appear　a　trifling　technical　matter　of　detail；　but　its　great　practical　value　must　be　my　excuse　for　mentioning　it。


1838。　Invention　of　Safety　Foundry　Ladle。

The　safety　ladle　is　described　in　the　text；　p。　　202。


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。