Plumier，Bergeron，andmanyotherwriters。
TheworkofPlumierisespeciallyelaborate，enteringintotheconstructionofthelatheinitsvariousparts，themakingofthetoolsandcutters，andthedifferentmotionstobegiventothemachinebymeansofwheels，eccentrics，andotherexpedients，amongstwhichmaybementionedoneverymuchresemblingthesliderestandplaning-machinecombined。*
[footnote……
Itconsistedoftwoparallelbarsofwoodorironconnectedtogetheratbothextremitiesbyboltsorkeysofsufficientwidthtoadmitofthearticlerequiredtobeplaned。Amoveableframewasplacedbetweenthetwobars，motionbeinggiventoitbyalongcylindricalthreadactingonanytoolputintotheslidingframe，and，consequently，causingthescrew，bymeansofahandleateachendofit，topushordrawthepointorcutting-edgeofthetooleitherway——Mr。GeorgeRennie’sPrefacetoBuchanan’sPracticalEssaysonMillWork，3rdEd。xli。
FromthisworkitappearsthatturninghadlongbeenafavouritepursuitinFrancewithamateursofallranks，whosparednoexpenseinthecontrivanceandperfectionofelaboratemachineryfortheproductionofcomplexfigures。*
[footnote……
TurningwasafavouriteamusementamongsttheFrenchnoblesoflastcentury，manyofwhomacquiredgreatdexterityintheart，whichtheyturnedtoaccountwhencompelledtoemigrateattheRevolution。LouisXVI。himselfwasaverygoodlocksmith，andcouldhaveearnedafairlivingatthetrade。OurownGeorgeIII。wasagoodturner，andwaslearnedinwheelsandtreadles，chucksandchisels。HenryMayhewsays，ontheauthorityofanoldworkingturner，that，withaverageindustry，theKingmighthavemadefrom40s。to50s。a-weekasahardwoodandivoryturner。LordJohnHay，thoughone-armed，wasanadeptatthelatter，andLordGraywasanothercapitalturner。IndeedthelateMr。Holtzapffel’selaboratelyillustratedtreatisewaswrittenquiteasmuchforamateursasforworkingmechanics。AmongothernoblehandicraftsmenwemaymentionthelateLordDouglas，whocultivatedbookbinding。LordTraquair’sfancywascutlery，andonecouldnotcometohiminamorewelcomefashionthanwithapairofoldrazorstosetup。
TherewasatthattimeagreatpassionforautomatainFrance，whichgaverisetomanyhighlyingeniousdevices，suchasCamus’sminiaturecarriagemadeforLouisXIV。whenachild，Degennes’mechanicalpeacock，Vancanson’sduck，andMaillardet’sconjuror。Ithadtheeffectofintroducingamongthehigherorderofartistshabitsofniceandaccurateworkmanshipinexecutingdelicatepiecesofmachinery；andthesamecombinationofmechanicalpowerswhichmadethesteelspidercrawl，theduckquack，orwavedthetinyrodofthemagician，contributedinfutureyearstopurposesofhigherimport，——thewheelsandpinions，whichintheseautomataalmosteludedthehumansensesbytheirminuteness，reappearinginmoderntimesinthestupendousmechanismofourself-actinglathes，spinning-mules，andsteam-engines。”Inourowncountry，”saysProfessorWillis，”theliteratureofthissubjectissodefectivethatitisverydifficulttodiscoverwhatprogressweweremakingduringtheseventeenthandeighteenthcenturies。”*
[footnote……
ProfessorWILLIS，LecturesontheResultsoftheGreatExhibitionof1851，lstseries，p。306。
Webelievethefacttobe，thattheprogressmadeinEnglanddowntotheendoflastcenturyhadbeenverysmallindeed，andthatthelathehadexperiencedlittleornoimprovementuntilMaudslaytookitinhand。Nothingseemstohavebeenknownofthesliderestuntilhere-inventeditandappliedittotheproductionofmachineryofafarmoreelaboratecharacterthanhadeverbeforebeencontemplatedaspossible。ProfessorWillissaysthatBramah’s，inotherwordsMaudslay’s，sliderestof1794issodifferentfromthatdescribedintheFrench’Encyclopediein1772，thatthetwocouldnothavehadacommonorigin。WearethereforeledtotheconclusionthatMaudslay’sinventionwasentirelyindependentofallthathadgonebefore，andthathecontriveditforthespecialpurposeofovercomingthedifficultieswhichhehimselfexperiencedinturningoutduplicatepartsinlargenumbers。Atallevents，hewassoearlyandzealousapromoterofitsuse，thatwethinkhemay，intheeyesofallpracticalmechanics，standastheparentofitsintroductiontotheworkshopsofEngland。
ItisunquestionablethatatthetimewhenMaudslaybegantheimprovementofmachine-tools，themethodsofworkinginwoodandmetalswereexceedinglyimperfect。Mr。WilliamFairbairnhasstatedthatwhenhefirstbecameacquaintedwithmechanicalengineering，aboutsixtyyearsago，therewerenoself-actingtools；everythingwasexecutedbyhand。Therewereneitherplaning，slotting，norshapingmachines；andthewholestockofanengineeringormachineestablishmentmightbesummedupinafewill-constructedlathes，andafewdrillsandboringmachinesofrudeconstruction。*
[footnote……
AddressdeliveredbeforetheBritishAssociationatManchesterin1861；andUsefulInformationforEngineers，1stseries，p。22。
Ourmechanicswereequallybackwardincontrivancesforworkinginwood。Thus，whenSirSamuelBenthammadeatourthroughthemanufacturingdistrictsofEnglandin1791，hewassurprisedtofindhowlittlehadbeendonetosubstitutetheinvariableaccuracyofmachineryfortheuncertaindexterityofthehumanhand。Steam-powerwasasyetonlyemployedindrivingspinning-machines，rollingmetals，pumpingwater，andsuchlikepurposes。Intheworkingofwoodnomachineryhadbeenintroducedbeyondthecommonturning-latheandsomesaws，andafewboringtoolsusedinmakingblocksforthenavy。
Evensawsworkedbyinanimateforceforslittingtimber，thoughinextensiveuseinforeigncountries，werenowheretobefoundinGreatBritain。*
[footnote……
LifeofSirSamuelBentham，97-8。
Aseverythingdependedonthedexterityofhandandcorrectnessofeyeoftheworkmen，theworkturnedoutwasofveryunequalmerit，besidesbeingexceedinglycostly。Evenintheconstructionofcomparativelysimplemachines，theexpensewassogreatastopresentaformidableobstacletotheirintroductionandextensiveuse；andbutfortheinventionofmachine-makingtools，theuseofthesteam-engineinthevariousformsinwhichitisnowappliedfortheproductionofpowercouldneverhavebecomegeneral。
Inturningapieceofworkontheold-fashionedlathe，theworkmanappliedandguidedhistoolbymeansofmuscularstrength。Theworkwasmadetorevolve，andtheturner，holdingthecuttingtoolfirmlyuponthelong，straight，guidingedgeoftherest，alongwhichhecarriedit，andpressingitspointfirmlyagainstthearticletobeturned，wasthusenabledtoreduceitssurfacetotherequiredsizeandshape。Somedexterousturnerswereable，withpracticeandcarefulness，toexecuteverycleverpiecesofworkbythissimplemeans。Butwhenthearticletobeturnedwasofconsiderablesize，andespeciallywhenitwasofmetal，theexpenditureofmuscularstrengthwassogreatthattheworkmansoonbecameexhausted。Theslightestvariationinthepressureofthetoolledtoanirregularityofsurface；andwiththeutmostcareontheworkman’spart，hecouldnotavoidoccasionallycuttingalittletoodeep，inconsequenceofwhichhemustnecessarilygooverthesurfaceagain，toreducethewholetothelevelofthataccidentallycuttoodeep；
andthuspossiblythejobwouldbealtogetherspoiledbythediameterofthearticleunderoperationbeingmadetoosmallforitsintendedpurpose。
Theintroductionofthesliderestfurnishedacompleteremedyforthissourceofimperfection。Theprincipleoftheinventionconsistsinconstructingandfittingtherestsothat，insteadofbeingscreweddowntooneplace，andthetoolinthehandsoftheworkmantravellingoverit，therestshallitselfholdthecuttingtoolfirmlyfixedinit，andslidealongthesurfaceofthebenchinadirectionexactlyparallelwiththeaxisofthework。Beforeitsinventionvariousmethodshadbeentriedwiththeobjectofenablingtheworktobeturnedtrueindependentofthedexterityoftheworkman。Thus，asquaresteelcutterusedtobefirmlyfixedinabed，alongwhichitwaswedgedfrompointtopointofthework，andtolerableaccuracywasinthiswaysecured。Butthesliderestwasmuchmoreeasilymanaged，andtheresultwasmuchmoresatisfactory。
Allthattheworkmanhadtodo，afterthetoolwasfirmlyfittedintotherest，wasmerelytoturnascrew-handle，andthusadvancethecutteralongthefaceoftheworkasrequired，withanexpenditureofstrengthsoslightasscarcelytobeappreciable。Andeventhislabourhasnowbeengotridof；for，byanarrangementofthegearing，theslideitselfhasbeenmadeself-acting，andadvanceswiththerevolutionoftheworkinthelathe，whichthussuppliestheplaceoftheworkman’shand。Theaccuracyoftheturningdonebythisbeautifulyetsimplearrangementisasmechanicallyperfectasworkcanbe。Thepairofsteelfingerswhichholdthecuttingtoolfirmlyintheirgraspnevertire，anditmovesalongthemetaltobecutwithanaccuracyandprecisionwhichthehumanhand，howeverskilled，couldneverequal。
Theeffectsoftheintroductionofthesliderestwereveryshortlyfeltinalldepartmentsofmechanism。Thoughithadtoencountersomeoftheridiculewithwhichnewmethodsofworkingareusuallyreceived，andforatimewasspokenofinderisionas”Maudslay’sGo-cart，”——itspracticaladvantagesweresodecidedthatitgraduallymadeitsway，andbecameanestablishedtoolinallthebestmechanicalworkshops。Itwasfoundalikecapableofexecutingthemostdelicateandthemostponderouspiecesofmachinery；andasslide-lathescouldbemanufacturedtoanyextent，machinery，steam-engines，andallkindsofmetalworkcouldnowbeturnedoutinaquantityandatapricethat，butforitsuse，couldneverhavebeenpracticable。Incourseoftimevariousmodificationsofthemachinewereintroduced——suchastheplaningmachine，thewheel-cuttingmachine，andotherbeautifultoolsontheslide-restprinciple，——theresultofwhichhasbeenthatextraordinarydevelopmentofmechanicalproductionandpowerwhichissocharacteristicafeatureoftheagewelivein。”Itisnot，indeed，sayingatalltoomuchtostate，”saysMr。
Nasmyth，*
[footnote……
RemarksontheIntroductionoftheSlidePrincipleinToolsandMachinesemployedintheProductionofMachinery，inBuchanan’sPracticalEssaysonMillWorkandotherMachinery。3rded。p。397。
amostcompetentjudgeinsuchamatter，”thatitsinfluenceinimprovingandextendingtheuseofmachineryhasbeenasgreatasthatproducedbytheimprovementofthesteam-engineinrespecttoperfectingmanufacturesandextendingcommerce，inasmuchaswithouttheaidofthevastaccessiontoourpowerofproducingperfectmechanismwhichitatoncesupplied，wecouldneverhaveworkedoutintopracticalandprofitableformstheconceptionsofthosemastermindswho，duringthelasthalfcentury，havesosuccessfullypioneeredthewayformankind。Thesteam-engineitself，whichsuppliesuswithsuchunboundedpower，owesitspresentperfectiontothismostadmirablemeansofgivingtometallicobjectsthemostpreciseandperfectgeometricalforms。Howcouldwe，forinstance，havegoodsteam-enginesifwehadnotthemeansofboringoutatruecylinder，orturningatruepiston-rod，orplaningavalveface?Itisthisalonewhichhasfurnisheduswiththemeansofcarryingintopracticetheaccumulatedresult’sofscientificinvestigationonmechanicalsubjects。Itwouldbeblamableindeed，”continuesMr。
Nasmyth，”afterhavingendeavouredtosetforththevastadvantageswhichhavebeenconferredonthemechanicalworld，andthereforeonmankindgenerally，bytheinventionandintroductionoftheSlideRest，wereItosuppressthenameofthatadmirableindividualtowhomweareindebtedforthispowerfulagenttowardstheattainmentofmechanicalperfection。IalludetoHenryMaudslay，whoseusefullifewasenthusiasticallydevotedtothegrandobjectofimprovingourmeansofproducingperfectworkmanshipandmachinery：tohimwearecertainlyindebtedforthesliderest，and，consequently，tosaytheleast，weareindirectlysoforthevastbenefitswhichhaveresultedfromtheintroductionofsopowerfulanagentinperfectingourmachineryandmechanismgenerally。Theindefatigablecarewhichhetookininculcatinganddiffusingamonghisworkmen，andmechanicalmengenerally，soundideasofpracticalknowledgeandrefinedviewsofconstruction，haverenderedandeverwillcontinuetorenderhisnameidentifiedwithallthatisnobleintheambitionofaloverofmechanicalperfection。”
OneofthefirstusestowhichMr。Maudslayappliedtheimprovedsliderest，whichheperfectedshortlyafterbeginningbusinessinMargaretStreet，CavendishSquare，wasinexecutingtherequisitetoolsandmachineryrequiredbyMr。afterwardsSirMarcIsambard