men of invention and industry-第31节

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according　to　the　details　he　enclosed。　　〃I　have　warmed　up；〃　he

concludes；　〃an　old　idea；　and　can　make　a　machine　in　which　the

pentagraph　and　the　leading　screw　will　all　be　contained　in　the

beam；　and　the　pattern　and　piece　to　be　cut　will　remain　at　rest

fixed　upon　a　lath　of　cast　iron　or　stout　steel。〃　　Watt　is　very

particular　in　all　his　details：　〃I　am　sorry；〃　he　says　in　one　note；

〃to　trouble　you　with　so　many　things；　but　the　alterations　on　this

spindle　and　socket　＇he　annexes　a　drawing＇　may　wait　your

convenience。〃　　In　a　further　note；　Watt　says。　　〃The　drawing　for

the　parallel　lathe　is　ready；　but　I　have　been　sadly　puzzled　about

the　application　of　the　leading　screws　to　the　cranes　in　the　other。



I　think；　however；　I　have　now　got　the　better　of　the　difficulties；

and　made　it　more　certain；　as　well　as　more　simple；　than　it　was。　　I

have　done　an　excellent　head　of　John　Hunter　in　hard　white　in

shorter　time　than　usual。　　I　want　to　show　it　you　before　I　repair

it。〃



At　last　Watt　seems　to　have　become　satisfied：　〃The　lathe；〃　he

says；　〃is　very　much　improved；　and　you　seem　to　have　given　the

finishing　blow　to　the　roofed　frame；　which　appears　perfectly

stiff。　　I　had　some　hours'　intense　thinking　upon　the　machine　last

night；　and　have　made　up　my　mind　on　it　at　last。　　The　great

difficulty　was　about　the　application　of　the　band；　but　I　have

settled　it　to　be　much　as　at　present。〃



Watt's　letters　to　Murdock　are　most　particular　in　details；

especially　as　to　screws；　nuts；　and　tubes；　with　strengths　and

dimensions；　always　illustrated　with　pen…and…ink　drawings。　　And

yet　all　this　was　done　merely　for　mechanical　amusement；　and　not

for　any　personal　pecuniary　advantage。　　While　Watt　was　making

experiments　as　to　the　proper　substances　to　be　carved　and　drilled；

he　also　desired　Murdock　to　make　similar　experiments。　　〃The

nitre；〃　he　said　in　one　note；　〃seems　to　do　harm；　the　fluor

composition　seems　the　best　and　hardest。　　Query；　what　would　some

calcined　pipe…clay　do？　　If　you　will　calcine　some　fire…clay　by　a

red　heat　and　pound　it；about　a　pound；and　send　it　to　me；　I

shall　try　to　make　you　a　mould　or　two　in　Henning's　manner　to　cast

this　and　the　sulphur　acid　iron　in。　　I　have　made　a　screwing　tool

for　wood　that　seems　to　answer；　also　one　of　a　one…tenth　diameter

for　marble；　which　does　very　well。〃　　In　another　note；　Watt　says：

〃I　find　my　drill　readily　makes　2400　turns　per　minute；　even　with

the　large　drill　you　sent　last；　if　I　bear　lightly；　a　three…quarter

ferril　would　run　about　3000；　and　by　an　engine　that　might　be

doubled。〃



The　materials　to　be　drilled　into　medallions　also　required　much

consideration。　　〃I　am　much　obliged　to　you；〃　said　Watt；　〃for　the

balls；　etc。；　which　answer　as　well　as　can　be　expected。　　They　make

great　progress　in　cutting　the　crust　（Ridgways）　or　alabaster；　and

also　cut　marble；　but　the　harder　sorts　soon　blunt　them。　　At　any

rate；　marble　does　not　do　for　the　medallions；　as　its　grain

prevents　its　being　cut　smooth；　and　its　semi…transparence　hurts

the　effect。　　I　think　Bristol　lime；　or　shell　lime；　pressed　in　your

manner；　would　have　a　good　effect。　　When　you　are　at　leisure；　I

shall　thank　you　for　a　few　pieces；　and　if　some　of　them　are　made

pink　or　flesh　colour；　they　will　look　well。　　I　used　the　ball　quite

perpendicular；　and　it　cut　well；　as　most　of　the　cutting　is

sideways。　　I　tried　a　fine　whirling　point；　but　it　made　little

progress；　another　with　a　chisel　edge　did　almost　as　well　as　the

balls；　but　did　not　work　so　pleasantly。　　I　find　a　triangular

scraping　point　the　best；　and　I　think　from　some　trials　it　should

be　quite　a　sharp　point。　　The　wheel　runs　easier　than　it　did；　but

has　still　too　much　friction。　　I　wished　to　have　had　an　hour's

consultation　with　you；　but　have　been　prevented　by　sundry　matters

among　others　by　that　plaguey　stove；　which　is　now　in　your　hands。〃



Watt　was　most　grateful　to　Murdock　for　his　unvarying　assistance。　

In　January；　1813；　when　Watt　was　in　his　seventy…seventh　year；　he

wrote　to　Murdock；　asking　him　to　accept　a　present　of　a　lathe　〃I

have　not　heard　from　you；〃　he　says；　〃in　reply　to　my　letter　about

the　lathe；　and；　presuming　you　are　not　otherwise　provided；　I　have

bought　it；　and　request　your　acceptance　of　it。　　At　present；　an

alteration　for　the　better　is　making　in　the　oval　chuck；　and　a　few

additional　chucks；　rest；　etc。；　are　making　to　the　lathe。　　When

these　are　finished；　I　shall　have　it　at　Billinger's　until　you

return；　or　as　you　otherwise　direct。　　I　am　going　on　with　my

drawings　for　a　complete　machine；　and　shall　be　glad　to　see　you

here　to　judge　of　them。〃



The　drawings　were　made；　but　the　machine　was　never　finished。　

〃Invention；〃　said　Watt；　〃goes　on　very　slowly　with　me　now。〃　　Four

years　later；　he　was　still　at　work；　but　death　put　a　stop　to　his

〃diminishing…machine。〃　It　is　a　remarkable　testimony　to　the　skill

and　perseverance　of　a　man　who　had　already　accomplished　so　much；

that　it　is　almost　his　only　unfinished　work。　　Watt　died　in　1819；

in　the　eighty…third　year　of　his　age；　to　the　great　grief　of

Murdock；　his　oldest　and　most　attached　friend　and　correspondent。



Meanwhile；　the　firm　of　Boulton　and　Watt　continued。　　The　sons　of

the　two　partners　carried　it　on；　with　Murdock　as　their　Mentor。　　He

was　still　full　of　work　and　inventive　power。　　In　1802；　he　applied

the　compressed　air　of　the　Blast　Engine　employed　to　blow　the

cupolas　of　the　Soho　Foundry；　for　the　purpose　of　driving　the　lathe

in　the　pattern　shop。　　It　worked　a　small　engine；　with　a　l2…inch

cylinder　and　18…inch　stroke；　connected　with　the　lathe；　the　speed

being　regulated　as　required　by　varying　the　admission　of　the

blast。　　This　engine　continued　in　use　for　about　thirty…five　years。



In　1803　Murdock　experimented　on　the　power　of　high…pressure　steam

in　propelling　shot；　and　contrived　a　steam…engine　with　which　he

made　many　trials　at　Soho；　thereby　anticipating　the　apparatus

contrived　by　Mr。　Perkins　many　years　later。



In　1810　Murdock　took　out　a　patent　for　boring　steam…pipes　for

water；　and　cutting　columns　out　of　solid　blocks　of　stone；　by　means

of　a　cylindrical　crown　saw。　　The　first　machine　was　used　at　Soho；

and　afterwards　at　Mr。　Rennie's　Works　in　London；　and　proved　quite

successful。　　Among　his　other　inventions　were　a　lift　worked　by

compressed　air；　which　raised　and　lowered　the　castings　from　the

boring…mill　to　the　level　of　the　foundry　and　the　canal　bank。　　He

used　the　same　kind　of　power　to　ring　the　bells　in　his　house　at

Sycamore　Hill；　and　the　contrivance　was　afterwards　adopted　by　Sir

Walter　Scott　in　his　house　at　Abbotsford。



Murdock　was　also　the　inventor　of　the　well…known　cast…iron　cement；

so　extensively　used　in　engine　and　machine　work。　　The　manner　in

which　he　was　led　to　this　invention　affords　a　striking

illustration　of　his　quickness　of　observation。　　Finding　that　some

iron…borings　and　sal…ammoniac　had　got　accidently　mixed　together

in　his　tool…chest；　and　rusted　his　saw…blade　nearly　through；　he

took　note　of　the　circumstance；　mixed　the　articles　in　various

proportions；　and　at　length　arrived　at　the　famous　cement；　which

eventually　became　an　article　of　extensive　manufacture　at　the　Soho

Works。



Murdock's　ingenuity　was　constantly　at　work；　even　upon　matters

which　lay　entirely　outside　his　special　vocation。　　The　late　Sir

William　Fairbairn　informed　us　that　he　contrived　a　variety　of

curious　machines　for　consolidating　peat　moss；　finely　ground　and

pulverised；　under　immense　pressure；　and　which；　when　consolidated；

could　be　moulded　into　beautiful　medals；　armlets；　and　necklaces。　

The　material　took　the　most　brilliant　polish　and　had　the

appearance　of　the　finest　jet。



Observing　that　fish…skins　might　be　used　as　an　economical

substitute　for　isinglass；　he　went　up　to　London　on　one　occasion　in

order　to　explain　to　brewers　the　best　method　of　preparing　and

using　them。　　He　occupied　handsome　apartments；　and；　little

regarding　the　splendour　of　the　drawing…room；　he　hung　the

fish…skins　up　against　the　walls。　　His　landlady　caught　him　one　day

when　he　was　about　to　bang　up　a　wet　cod's　skin！　　He　was　turned　out

at　once；　with　all　his　fish。　　While　in　town　on　this　errand；　it

occurred　to　him　that　a　great　deal　of　power　was　wasted　in　treading

the　streets　of　London！　　He　conceived　the　idea　of　using　the

streets　and　roadways　as　a　grand　tread…mill；　under　which　the　waste

power　might　be　stored　up　by　mechanical　methods　and　turned　to

account。　　He　had　also　an　idea　of　storing　up　the　power　of　the

tides；　and　of　running　water；　in　the　same　way。　　The　late　Charles

Babbage；　F。R。S。；　entertained　a　similar　idea　about　using　springs

of　Ischia　or　of　the　geysers　of　Iceland　as　a　power　necessary　for

condensing　gases；　or　perhaps　for　the　storage　of　electricity。＇12＇　

The　latter；　when　perfected；　will　probably　be　the　greatest

invention　of　the　next　half　century。



Another　of　Murdock's'　ingenious　schemes；　was　his　proposed　method

of　transmitting　letters　and　packages　through　a　tube　exhausted　by

an　air…pump。　　This　project　led　to　the　Atmospheric　Railway；　the

success　of　which；　so　far　as　it　went；　was　due　to　the