an autobiography-第25部分

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entleman　who　took　a　fancy　for　the　model　when　he　came　to　purchase　some　of　my　father's　works。

The　price　I　charged　for　my　models　was　#10；　and　with　the　pecuniary　results　I　made　over　one…third　to　my　father；　as　a　sort　of　help　to　remunerate　him　for　my　〃keep；〃　and　with　the　rest　I　purchased　tickets　of　admission　to　certain　classes　in　the　University。　　I　attended　the　Chemistry　course　under　Dr。　Hope；　the　Geometry　and　Mathematical　course　under　Professor　Wallace；　and　the　Natural　Philosophy　course　under　my　valued　friend　and　patron　Professor　Leslie。　　What　with　my　attendance　upon　the　classes；　and　my　workshop　and　drawing　occupations；　my　time　did　not　hang　at　all　heavy　on　my　hands。

I　got　up　early　in　the　mornings　to　work　at　my　father's　lathe；　and　I　sat　up　late　at　night　to　do　the　brass　castings　in　my　bedroom。　　Some　of　this；　however；　I　did　during　the　day…time；　when　not　attending　the　University　classes。　　The　way　in　which　I　converted　my　bedroom　into　a　brass　foundry　was　as　follows：　　I　took　up　the　carpet　so　that　there　might　be　nothing　but　the　bare　boards　to　be　injured　by　the　heat。　　My　furnace　in　the　grate　was　made　of　four　plates　of　stout　sheet…iron；　lined　with　fire…brick；　corner　to　corner。　　To　get　the　requisite　sharp　draught　I　bricked　up　with　single　bricks　the　front　of　the　fireplace；　leaving　a　hole　at　the　back　of　the　furnace　for　the　short　pipe　just　to　fit　into。　　The　fuel　was　generally　gas　coke　and　cinders　saved　from　the　kitchen。　　The　heat　I　raised　was　superba　white　heat；　sufficient　to　melt　in　a　crucible　six　or　eight　pounds　of　brass。

Then　I　had　a　box　of　moulding　sand；　where　the　moulds　were　gently　rammed　in　around　the　pattern　previous　to　the　casting。　　But　how　did　I　get　my　brass？　　All　the　old　brassworks　in　my　father's　workshop　drawers　and　boxes　were　laid　under　contribution。　　This　brass　being　for　the　most　part　soft　and　yellow；　I　made　it　extra　hard　by　the　addition　of　a　due　proportion　of　tin。　　It　was　then　capable　of　retaining　a　fine　edge。　　When　I　had　exhausted　the　stock　of　old　brass；　I　had　to　buy　old　copper；　or　new；　in　the　form　of　ingot　or　tile　copper；　and　when　melted　I　added　to　it　one…eighth　of　its　weight　of　pure　tin；　which　yielded　the　strongest　alloy　of　the　two　metals。　　When　cast　into　any　required　form　this　was　a　treat　to　work；　so　sound　and　close　was　the　grain；　and　so　durable　in　resisting　wear　and　tear。　　This　is　the　true　bronze　or　gun　metal。

When　melted；　the　liquid　brass　was　let　into　the　openings；　until　the　whole　of　the　moulds　were　filled。　　After　the　metal　cooled　it　was　taken　out；　and　when　the　room　was　sorted　up　no　one　could　have　known　that　my　foundry　operations　had　been　carried　on　in　my　bedroom。　　My　brass　foundry　was　right　over　my　father's　bedroom。　　He　had　forbidden　me　to　work　late　at　night；　as　I　did　occasionally　on　the　sly。　　Sometimes　when　I　ought　to　have　been　asleep　I　was　detected　by　the　sound　of　the　ramming　in　of　the　sand　of　the　moulding　boxes。　　On　such　occasions　my　father　let　me　know　that　I　was　disobeying　his　orders　by　rapping　on　the　ceiling　of　his　bedroom　with　a　slight　wooden　rod　of　ten　feet　that　he　kept　for　measuring　purposes。　　But　I　got　over　that　difficulty　by　placing　a　bit　of　old　carpet　under　my　moulding　boxes　as　a　non…conductor　of　sound；　so　that　no　ramming　could　afterwards　be　heard。　My　dear　mother　also　was　afraid　that　I　should　damage　my　health　by　working　so　continuously。　　She　would　come　into　the　workroom　late　in　the　evening；　when　I　was　working　at　the　lathe　or　the　vice；　and　say；　〃Ye'll　kill　yerself；　laddie；　by　working　so　hard　and　so　late〃。　　Yet　she　took　a　great　pride　in　seeing　me　so　busy　and　so　happy。

Nearly　the　whole　of　my　steam…engine　models　were　made　in　my　father's　workroom。　　His　foot…lathe　and　stove；　together　with　my　brass　casting　arrangements　in　my　bedroom；　answered　all　my　purposes　in　the　way　of　model　making。　　But　I　had　at　times　to　avail　myself　of　the　smithy　and　foundry　that　my　kind　and　worthy　friend；　George　Douglass；　had　established　in　the　neighbourhood。　　He　had　begun　business　as　〃a　jobbing　smith；〃　but　being　a　most　intelligent　and　energetic　workman；　he　shot　ahead　and　laid　the　foundations　of　a　large　trade　in　steam…engines。　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　exp