an autobiography-第23部分

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When　I　had　any　part　of　a　job　in　hand　that　was　beyond　the　capabilities　of　my　father's　lathe；　or　my　bedroom　casting　apparatus；　I　immediately　went　to　Douglass's　smithy；　where　every　opportunity　was　afforded　me　for　carrying　on　my　larger　class　of　work。

His　place　was　only　about　five　minutes'　walk　from　my　father's　house。　I　had　the　use　of　his　large　turning…lathe；　which　was　much　more　suitable　for　big　or　heavy　work　than　the　lathe　at　home。　　When　any　considerable　bit　of　steel　or　iron　forging　had　to　be　done；　a　forge　fire　and　anvil　were　always　placed　at　my　service。　　In　making　my　flywheels　for　the　sectional　models　of　steam…engines　I　had　a　rather　neat　and　handy　way　of　constructing　them。　　The　boss　of　the　wheel　of　brass　was　nicely　bored；　the　arm…holes　were　carefully　drilled　and　taped；　so　as　to　allow　the　arms　which　I　had　turned　to　be　screwed　in　and　appear　like　neat　columns　of　round　wrought　iron　or　steel　screwed　into　the　boss　of　the　flywheel。

In　return　for　the　great　kindness　of　George　Douglass　in　allowing　me　to　have　the　use　of　his　foundry；　I　resolved　to　present　him　with　a　specimen　of　my　handiwork。　　I　desired　to　try　my　powers　in　making　a　more　powerful　steam…engine　than　I　had　as　yet　attempted　to　construct；　in　order　to　drive　the　large　turning…lathe　and　the　other　tools　and　machinery　of　his　small　foundry。　　I　accordingly　set　to　work　and　constructed　a　　direct…acting；　high…pressure　steam…engine；　with　a　cylinder　four　inches　in　diameter。　　I　use　the　term　direct　acting；　because　I　dispensed　with　the　beam　and　parallel　motion；　which　was　generally　considered　the　correct　mode　of　transferring　the　action　of　the　piston　to　the　crank。

The　result　of　my　labours　was　a　very　efficient　steam…engine；　which　set　all　the　lathes　and　mechanical　tools　in　brisk　activity　of　movement。　It　had　such　an　enlivening　effect　upon　the　workmen　that　George　Douglass　afterwards　told　me　that　the　busy　hum　of　the　wheels；　and　the　active；　smooth；　rhythmic　sound　of　the　merry　little　engine　had；　through　some　sympathetic　agency；　so　quickened　the　stroke　of　every　hammer；　chisel；　and　file　in　his　workmen's　hands；　that　it　nearly　doubled　the　output　of　work　for　the　same　wages！

The　sympathy　of　activity　acting　upon　the　workmen's　hands　cannot　be　better　illustrated　than　by　a　story　told　me　by　my　father。　　A　master　tailor　in　a　country　town　employed　a　number　of　workmen。　　They　had　been　to　see　some　tragic　melodrama　performed　by　some　players　in　a　booth　at　the　fair。　　A　very　slow；　doleful；　but　catching　air　was　played；　which　so　laid　hold　of　the　tailors'　fancy　that　for　some　time　after　they　were　found　slowly　whistling　or　humming　the　doleful　ditty；　the　movement　of　their　needles　keeping　time　to　it；　the　result　was　that　the　clothing　that　should　have　been　sent　home　on　Saturday　was　not　finished　until　the　Wednesday　following。　　The　music　had　done　it！　　The　master　tailor；　being　something　of　a　philosopher；　sent　his　men　to　the　play　again；　but　he　arranged　that　they　should　be　treated　with　lively　merry　airs。　The　result　was　that　the　lively　airs　displaced　the　doleful　ditty；　and　the　tailors'　needles　again　reverted　to　even　more　than　their　accustomed　quickness。

However　true　the　story　may　be；　it　touches　an　important　principle　in　regard　to　the　stimulation　of　activity　by　the　rapid　movements　or　sounds　of　machinery；　which　influence　every　workman　within　their　sight　or　hearing。　　We　all　know　the　influence　of　a　quick　merry　air；　played　by　fife　and　drum；　upon　the　step　and　marching　of　a　regiment　of　soldiers。　It　is　the　same　with　the　quick　movements　of　a　steam…engine　upon　the　activity　of　workmen。

I　may　add　that　my　worthy　friend；　George　Douglass；　derived　other　advantages　from　the　construction　of　my　steam…engine。　　Being　of　an　enterprising　disposition　he　added　another　iron　foundry　to　his　smaller　shops；　he　obtained　many　good　engineering　tools；　and　in　course　of　time　he　began　to　make　steam…engines　for　agricultural　purposes。　　These　were　used　in　lieu　of　horse　power　for　thrashing　corn；　and　performing　several　operations　that　used　to　be　done　by　hand　labour　in　the　farmyards。　Orders　came　in　rapidly；　and　before　long　the　chimneys　of　Douglass's　steam…engines　were　as　familiar　in　the　country　round　Edinburgh　as　corn　stacks。　　All　the　large　farms；　especially　in　Midlothian　and　East　Lothian；　were　supplied　with　his　steam…engines。　The　business　of　George　Douglass　became　very　large；　and　in　course　of　time　he　was　enabled　to　retire　with　a　considerable　fortune。

In　addition　to　the　steam…engine　which　I　presented　to　Douglass；　I　received　an　order　to　make　another　from　a　manufacturer　of　braiding。　His　machines　had　before　been　driven　by　hand　labour；　but　as　his　business　extended；　the　manufacturer　employed　me　to　furnish　him　with　all　engine　of　two…horse　power；　which　was　duly　constructed　and　set　to　work；　and　gave　him　the　highest　satisfaction。

＇Image＇　　James　Nasmyth's　Expansometer；　1826。

I　may　here　mention　that　one　of　my　earliest　attempts　at　original　contrivance　was　an　Expansometeran　instrument　for　measuring　in　bulk　all　metals　and　solid　substances。　　The　object　to　be　experimented　on　was　introduced　into　a　tube　of　brass；　with　as　much　water　round　it　as　to　fill　the　tube。　　The　apparatus　was　then　plunged　into　a　vessel　of　boiling　water；　or　heated　to　boiling　point；　when　the　total　expansion　of　the　bar　was　measured　by　a　graduated　scale；　as　seen　in　the　annexed　engraving。　By　this　simple　means　the　expansion　of　any　material　might　be　ascertained　under　various　increments　of　heat；　say　from　60deg　to　2l2deg。　It　was　simply　a　thermometer；　the　mass　marking　its　own　expansion。　Dr。　Brewster　was　so　much　pleased　with　the　apparatus　that　he　described　it　and　figured　it　in　the　Edinburgh　Philosophical　Journal；　of　which　he　was　then　editor。

＇Image＇　　The　road　steam…carriage。　　By　James　Nasmyth。

About　the　year　1827；　when　I　was　nineteen　years　old；　the　subject　of　steam　carriages　to　run　upon　common　roads　occupied　considerable　attention。　　Several　engineers　and　mechanical　schemers　had　tried　their　hands；　but　as　yet　no　substantial　results　had　come　of　their　attempts　to　solve　the　problem。　　Like　others；　I　tried　my　hand。　　Having　made　a　small　working　model　of　a　steam…carriage；　I　exhibited　it　before　the　members　of　the　Scottish　Society　of　Arts。　　The　performance　of　this　active　little　machine　was　so　gratifying　to　the　Society　that　they　requested　me　to　construct　one　of　such　power　as　to　enable　four　or　six　persons　to　be　conveyed　along　the　ordinary　roads。　　The　members　of　the　Society；　in　their　individual　capacity；　subscribed　#60；　which　they　placed　in　my　hands　as　the　means　for　carrying　out　their　project。

I　accordingly　set　to　work　at　once。　　I　had　the　heavy　parts　of　the　engine　and　carriage　done　at　Anderson's　foundry　at　Leith。　　There　was　in　Anderson's　employment　a　most　able　general　mechanic　named　Robert　Maclaughlan；　who　had　served　his　time　at　Carmichaels'　of　Dundee。　Anderson　possessed　some　excellent　tools；　which　enabled　me　to　proceed　rapidly　with　the　work。　　Besides；　he　was　most　friendly；　and　took　much　delight　in　being　concerned　in　my　enterprise。　　This　〃big　job〃　was　executed　in　about　four　months。　　The　steam…carriage　was　completed　and　exhibited　before　the　members　of　the　Society　of　Arts。　　Many　successful　trials　were　made　with　it　on　the　queensferry　Road；　near　Edinburgh。　The　runs　were　generally　of　four　or　five　miles；　with　a　load　of　eight　passengers　sitting　on　benches　about　three　feet　from　the　ground。

The　experiments　were　continued　for　nearly　three　months；　to　the　great　satisfaction　of　the　members。　　I　may　mention　that　in　my　steam…carriage　I　employed　the　waste　steam　to　create　a　blast　or　draught　by　discharging　it　into　the　short　chimney　of　the　boiler　at　its　lowest　part；　and　found　it　most　effective。　　I　was　not　at　that　time　aware　that　George　Stephenson　and　others　had　adopted　the　same　method；　but　it　was　afterwards　gratifying　to　me　to　find　that　I　had　been　correct　as　regards　the　important　uses　of　the　steam　blast　in　the　chimney。　　In　fact；　it　is　to　this　use　of　the　waste　steam　that　we　owe　the　practical　success　of　the　locomotive…engine　as　a　tractive　power　on　railways；　especially　at　high　speeds。

The　Society　of　Arts　did　not　attach　any　commercial　value　to　my　steam　road…carriage。　　It　was　merely　as　a　matter　of　experiment　that　they　had　invited　me　to　construct　it。　　When　it　proved　successful　they　made　me　a　present　of　the　entire　apparatus。　　As　I　was　anxious　to　get　on　with　my　studies；　and　to　prepare　for　the　work　of　practical　engineering；　I　proceeded　no　further。　　I　broke　up　the　steam…carriage　and　sold　the　two　small　high…pressure　engines；　provided　with　a　compact　and　strong　boiler；　for　#67；　a　sum　which　more　than　defrayed　all　the　expenses　of　the　construction　and　working　of　the　machine。

I　still　continued　to　make　investigations　as　to　the　powers　and　capabilities　of　the　steam…engine。　　There　were　numerous　breweries；　distilleries；　and　other　establishments；　near　Edinburgh；　where　such　engines　were　at　work。　　As　they　were　made　by　different　engineers；　I　was　desirous　of　seeing　them　and　making　sketches　of　them；　especially　when　there　was　any　special　peculiarity　in　their　construction。　　I　found　this　a　most　favourite　and　instructive　occupation。　　The　engine　tenters　became　very　friendly　with　me；　and　they　we　re　always　glad　to　see　me　interested　in　them　and　their　engines。　　They　were　especially　delighted　to　see　me　make　〃drafts；〃　as　they　called　my　sketches；　of　the　engines　under　their　charge。

My　father　sometimes　feared　that　my　too　close　and　zealous　application　to　engineering　work　might　have　a　bad　effect　upon　my　health。　　My　bedroom　work　at　brass　casting；　my　foundry　work　at　the　making　of　steam…engines；　and　my　studies　at　the　University　classes；　were　perhaps　too　much　for　a　lad　of　my　age；　just　when　I　was　in　the　hobbledehoy　statebetween　a　boy　and　a　man。　　Whether　his　apprehensions　were　warranted　or　not；　it　did　so　happen　that　I　was　attacked　with　typhus　fever　in　1828；　a　disease　that　was　then　prevalent　in　Edinburgh。　　I　had　a　narrow　escape　from　its　fatal　influence。　　But　thanks　to　my　good　constitution；　and　to　careful　nursing；　I　succeeded　in　throwing　off　the　fever；　and　after　due　time　recovered　my　usual　health　and　strength。

In　the　course　of　my　inspection　of　the　engines　made　by　different　makers；　I　was　impressed　with　the　superiority　of　those　made　by　the　Carmichaels　of　Dundee。　　They　were　excellent　both　in　design　and　in　execution。　I　afterwards　found　that　the　Carmichaels　were　among　the　first　of　the　Scottish　e