Theswallow-tailorunionjetwasalsohisinvention,andithassincecomeintogeneraluse。
WhilemanagingtheGas-works,oneofMr。Neilson’slaboursoflovewastheestablishmentanddirectionbyhimofaWorkmen’sInstitutionformutualimprovement。Havingbeenaworkmanhimself,andexperiencedthedisadvantagesofanimperfecteducationinearlylife,aswellasthebenefitsarisingfromimprovedcultureinlateryears,hedesiredtoimpartsomeoftheseadvantagestotheworkmeninhisemployment,whoconsistedchieflyofpersonsfromremotepartsoftheHighlandsorfromIreland。Mostofthemcouldnotevenread,andhisprincipaldifficultyconsistedinpersuadingthemthatitwasofanyusetolearn。ForsometimetheyresistedhispersuasionstoformaWorkmen’sInstitution,withaviewtotheestablishmentofalibrary,classes,andlectures,urgingasasufficientpleafornotjoiningit,thattheycouldnotread,andthatbookswouldbeofnousetothem。AtlastMr。Neilsonsucceeded,thoughwithconsiderabledifficulty,ininducingfourteenoftheworkmentoadopthisplan。
Eachmemberwastocontributeasmallsummonthly,tobelaidoutinbooks,theGasCompanyprovidingthememberswithacomfortableroominwhichtheymightmeettoreadandconverseintheeveningsinsteadofgoingtothealehouse。Thememberswereafterwardsallowedtotakethebookshometoread,andtheroomwasusedforthepurposeofconversationonthesubjectsofthebooksreadbythem,andoccasionallyforlecturesdeliveredbythemembersthemselvesongeography,arithmetic,chemistry,andmechanics。Theirnumbersincreasedsothattheroominwhichtheymetbecameinsufficientfortheiraccommodation,whentheGasCompanyprovidedthemwithanewandlargerplaceofmeeting,togetherwithalaboratoryandworkshop。
Intheformertheystudiedpracticalchemistry,andinthelattertheystudiedpracticalmechanics,makingforthemselvesanairpumpandanelectrifyingmachine,aswellaspreparingthevariousmodelsusedinthecourseofthelectures。Theeffectsontheworkmenwereeminentlybeneficial,andtheinstitutioncametobecitedasamongthemostvaluableofitskindinthekingdom。*
[footnote……
ArticlebyDugaldBannatyneinGlasgowMechanic’sMagazine,No。53,Dec。1824。
Mr。Neilsonthroughoutwatchedcarefullyoveritsworking,andexertedhimselfinallwaystopromoteitsusefulness,inwhichhehadthezealousco-operationoftheleadingworkmenthemselves,andthegratitudeofall。Ontheopeningofthenewandenlargedroomsin1825,wefindhimdeliveringanadmirableaddress,whichwasthoughtworthyofrepublication,togetherwiththereplyofGeorgeSutherland,oneoftheworkmen,inwhichMr。Neilson’sexertionsasitsfounderandchiefsupporterweregratefullyandforciblyexpressed。*
[footnote……
GlasgowMechanic’sMagazine,vol。iii。p。159。
ItwasduringtheperiodofhisconnectionwiththeGlasgowGas-worksthatMr。Neilsondirectedhisattentiontothesmeltingofiron。Hisviewsinregardtothesubjectwereatfirstsomewhatcrude,asappearsfromapaperreadbyhimbeforetheGlasgowPhilosophicalSocietyearlyin1825。Itappearsthatinthecourseoftheprecedingyearhisattentionhadbeencalledtothesubjectbyaniron-maker,whoaskedhimifhethoughtitpossibletopurifytheairblownintotheblastfurnaces,inlikemannerascarburettedhydrogengaswaspurified。Theironmastersupposedthatitwasthepresenceofsulphurintheairthatcausedblast-furnacestoworkirregularly,andtomakebadironinthesummermonths。Mr。Neilsonwasofopinionthatthiswasnotthetruecause,andhewasratherdisposedtothinkitattributabletothewantofadueproportionofoxygeninsummer,whentheairwasmorerarefied,besidescontainingmoreaqueousvapourthaninwinter。Hethereforethoughtthetrueremedywasinsomewayorothertothrowinagreaterproportionofoxygen;andhesuggestedthat,inordertodrytheair,itshouldbepassed,onitswaytothefurnace,throughtwolongtunnelscontainingcalcinedlime。Butfurtherinquiryservedtocorrecthisviews,andeventuallyledhimtothetruetheoryofblasting。
Shortlyafter,hisattentionwasdirectedbyMr。JamesEwingtoadefectinoneoftheMuirkirkblast-furnaces,situatedabouthalfamiledistantfromtheblowing-engine,whichwasfoundnottoworksowellasotherswhichweresituatedclosetoit。ThecircumstancesofthecaseledMr。Neilsontoformtheopinionthat,asairincreasesinvolumeaccordingtotemperature,ifheweretoheatitbypassingitthroughared-hotvessel,itsvolumewouldbeincreased,accordingtothewell-knownlaw,andtheblastmightthusbeenabledtodomoredutyinthedistantfurnace。HeproceededtomakeaseriesofexperimentsattheGas-works,tryingtheeffectofheatedairontheilluminatingpowerofgas,bybringingupastreamofitinatubesoastosurroundthegas-burner。Hefoundthatbythismeansthecombustionofthegaswasrenderedmoreintense,anditsilluminatingpowergreatlyincreased。Heproceededtotryasimilarexperimentonacommonsmith’sfire,byblowingthefirewithheatedair,andtheeffectwasthesame;thefirewasmuchmorebrilliant,andaccompaniedbyanunusuallyintensedegreeofheat。
Havingobtainedsuchmarkedresultsbythesesmallexperiments,itnaturallyoccurredtohimthatasimilarincreaseinintensityofcombustionandtemperaturewouldattendtheapplicationoftheprocesstotheblast-furnaceonalargescale;butbeingonlyagas-maker,hehadthegreatestdifficultyinpersuadinganyironmastertopermithimtomakethenecessaryexperiment’swithblast-furnacesactuallyatwork。Besides,histheorywasaltogetheratvariancewiththeestablishedpractice,whichwastosupplyairascoldaspossible,theprevailingideabeingthatthecoldnessoftheairinwinterwasthecauseofthebestironbeingthenproduced。
Actingontheseviews,theeffortsoftheironmastershadalwaysbeendirectedtothecoolingoftheblast,andvariousexpedientsweredevisedforthepurpose。Thustheregulatorwaspaintedwhite,asbeingthecoolestcolour;theairwaspassedovercoldwater,andinsomecasestheairpipeswereevensurroundedbyice,allwiththeobjectofkeepingtheblastcold。When,therefore,Mr。Neilsonproposedentirelytoreversetheprocess,andtoemployhotinsteadofcoldblast,theincredulityoftheironmastersmaywellbeimagined。What!Neilson,ameremakerofgas,undertaketoinstructpracticalmeninthemanufactureofiron!Andtosupposethatheatedaircanbeusedforthepurpose!Itwaspresumptionintheextreme,oratbestthemerevisionaryideaofapersonaltogetherunacquaintedwiththesubject!
Atlength,however,Mr。NeilsonsucceededininducingMr。CharlesMacintoshofCrossbasket,andMr。ColinDunlopoftheClydeIronWorks,toallowhimtomakeatrialofthehotairprocess。Inthefirstimperfectattemptstheairwasheatedtolittlemorethan80
degreesFahrenheit,yettheresultsweresatisfactory,andthescoriaefromthefurnaceevidentlycontainedlessiron。Hewasthereforedesirousoftryinghisplanuponamoreextensivescale,withtheobject,ifpossible,ofthoroughlyestablishingthesoundnessofhisprinciple。Inthishewasagooddealhamperedevenbythoseironmasterswhowerehisfriends,andhadpromisedhimtherequisiteopportunitiesformakingafairtrialofthenewprocess。
Theystronglyobjectedtohismakingthenecessaryalterationsinthefurnaces,andheseemedtobeasfarfromasatisfactoryexperimentasever。Inoneinstance,wherehehadsofarsucceededastobeallowedtoheattheblast-main,heaskedpermissiontointroducedeflectingplatesinthemainortoputabendinthepipe,soastobringtheblastmorecloselyagainsttheheatedsidesofthepipe,andalsoincreasetheareaofheatingsurface,inordertoraisethetemperaturetoahigherpoint;butthiswasrefused,anditwassaidthatifevenabendwereputinthepipethefurnacewouldstopworking。Theseprejudicesprovedaseriousdifficultyinthewayofourinventor,andseveralmoreyearspassedbeforehewasallowedtoputabendintheblast-main。Aftermanyyearsofperseverance,hewas,however,atlengthenabledtoworkouthisplanintoadefiniteshapeattheClydeIronWorks,anditspracticalvaluewasatonceadmitted。AtthemeetingoftheMechanicalEngineers’SocietyheldinMay,1859,Mr。Neilsonexplainedthathisinventionconsistedsolelyintheprincipleofheatingtheblastbetweentheengineandthefurnace,andwasnotassociatedwithanyparticularconstructionoftheintermediateheatingapparatus。This,hesaid,wasthecauseofitssuccess;andinsomerespectsitresembledtheinventionofhiscountryman,JamesWatt,who,inconnectionwiththesteam-engine,inventedtheplanofcondensingthesteaminaseparatevessel,andwassuccessfulinmaintaininghisinventionbynotlimitingittoanyparticularconstructionofthecondenser。OnthesameoccasionhetooktheopportunityofacknowledgingthefirmnesswithwhichtheEnglishironmastershadstoodbyhimwhenattemptsweremadetodeprivehimofthebenefitsofhisinvention;andtothemheacknowledgedhewasmainlyindebtedforthesuccessfulissueoftheseverecontestshehadtoundergo。Fortherewere,ofcourse,certainoftheironmasters,bothEnglishandScotch,supportersofthecauseoffreetradeinothers’inventions,whosoughttoresistthepatent,afterithadcomeintogeneraluse,andhadbeenrecognisedasoneofthemostvaluableimprovementsofmodemtimes。*
[footnote……
Mr。Mushetdescribeditas”awonderfuldiscovery,”andoneofthe”mostnovelandbeautifulimprovementsinhistime。”ProfessorGregoryofAberdeencharacterizeditas”thegreatestimprovementwithwhichhewasacquainted。”Mr。Jessop,anextensiveEnglishironmanufacturer,declaredittobe”ofasgreatadvantageintheirontradeasArkwright’smachinerywasinthecotton-spinningtrade;andMr。Fairbairn,inhiscontributionon”Iron”intheEncyclopaediaBritannica,saysthatit”haseffectedanentirerevolutionintheironindustryofGreatBritain,andformsthelasterainthehistoryofthismaterial。”
Thepatentwassecuredin1828foratermoffourteenyears;but,asMr。Neilsondidnothimselfpossesstherequisitecapitaltoenablehimtoperfecttheinvention,ortodefenditifattacked,hefounditnecessarytoinviteothergentlemen,abletosupporthimintheserespects,toshareitsprofits;retainingforhimselfonlythree-tenthsofthewhole。HispartnerswereMr。CharlesMacintosh,Mr。ColinDunlop,andMr。JohnWilsonofDundyvan。Thechargemadebythemwasonlyashillingatonforallironproducedbythenewprocess;thislowratebeingfixedinordertoensuretheintroductionofthepatentintogeneraluse,aswellastoreducetoaminimumthetemptationsoftheironmasterstoinfringeit。
Thefirsttrialsoftheprocessweremadeattheblast-furnacesofClydeandCalder;fromwhencetheuseofthehotblastgraduallyextendedtotheotheriron-miningdistricts。InthecourseofafewyearseveryfurnaceinScotland,withoneexceptionthatatCarron,hadadoptedtheimprovement;whileitwasalsoemployedinhalfthefurnacesofEnglandandWales,andinmanyofthefurnacesontheContinentandinAmerica。Incourseoftime,andwithincreasingexperience,variousimprovementswereintroducedintheprocess,moreparticularlyintheshapeoftheair-heatingvessels;thelastformadoptedbeingthatofacongeriesoftubes,similartothetubulararrangementintheboilerofthelocomotive,bywhichthegreatestextentofheatingsurfacewasprovidedforthethoroughheatingoftheair。Bythesemodificationsthetemperatureoftheairintroducedintothefurnacehasbeenraisedfrom240degreesto600degrees,orthetemperatureofmeltinglead。Toprotectthenozzleoftheair-pipeasitenteredthefurnaceagainsttheactionoftheintenseheattowhichitwassubjected,aspiralpipeforastreamofcoldwaterconstantlytoplayinhasbeenintroducedwithinthesidesoftheirontuyerethroughwhichthenozzlepasses;bywhichmeansthetuyereiskeptcomparativelycool,whilethenozzleoftheair-pipeiseffectuallyprotected。*
[footnote……
Theinventionofthetubularair-vesselsandthewater-tuyerebelongs,webelieve,toMr。JohnCondie,sometimemanageroftheBlairIronWorks。
Thisvaluableinventiondidnotescapetheusualfateofsuccessfulpatents,anditwasonseveraloccasionsthesubjectofprotractedlitigation。Thefirstactionoccurredin1832;buttheobjectorsshortlygavein,andrenewedtheirlicence。In1839,whentheprocesshadbecomegenerallyadoptedthroughoutScotland,and,indeed,wasfoundabsolutelyessentialforsmeltingthepeculiaroresofthatcountry——moreespeciallyMushet’sBlackBand——apowerfulcombinationwasformedamongsttheironmasterstoresistthepatent。Thelitigationwhichensuedextendedoverfiveyears,duringwhichperiodsometwentyactionswereproceedinginScotland,andseveralinEngland。Threejuriessatuponthesubjectatdifferenttimes,andonthreeoccasionsappealswerecarriedtotheHouseofLords。Onejurytrialoccupiedtendays,duringwhichahundredandtwowitnesseswereexamined;thelawcostsonbothsidesamounting,itissupposed,toatleast40,000L。Theresultwas,thatthenoveltyandmeritofMr。Neilson’sinventionwerefinallyestablished,andhewassecuredintheenjoymentofthepatentright。
Wearegratifiedtoadd,that,thoughMr。Neilsonhadtopartwithtwo-thirdsoftheprofitsoftheinventiontosecurethecapitalandinfluencenecessarytobringitintogeneraluse,herealizedsufficienttoenablehimtoenjoytheeveningofhislifeinpeaceandcomfort。Heretiredfromactivebusinesstoanestatewhichhepurchasedin1851intheStewartryofKirkcudbright,whereheisfoundreadytolendahandineverygoodwork——whetherinagriculturalimprovement,railwayextension,orthemoralandsocialgoodofthoseabouthim。MindfulofthesuccessofhisWorkmen’sInstitutionattheGlasgowGas-Works,hehas,almostathisowndoor,erectedasimilarInstitutionfortheuseoftheparishinwhichhispropertyissituated,thebeneficialeffectsofwhichhavebeenverymarkedinthedistrict。WemayaddthatMr。Neilson’smeritshavebeenrecognisedbymanyeminentbodies——bytheInstitutionofCivilEngineers,theChemicalSociety,andothers——thelasthonourconferredonhimbeinghiselectionasaMemberoftheRoyalSocietyin1846。
Theinventionofthehotblast,inconjunctionwiththediscoveryoftheBlackBandironstone,hashadanextraordinaryeffectuponthedevelopmentoftheiron-manufactureofScotland。Thecoalsofthatcountryaregenerallyunfitforcoking,andloseasmuchas55percent。intheprocess。Butbyusingthehotblast,thecoalcouldbesenttotheblast-furnaceinitsrawstate,bywhichalargesavingoffuelwaseffected。*
[footnote……
Mr。Mushetsays,”ThegreatestproduceinironperfurnacewiththeBlackBandandcoldblastneverexceeded60tonsa-week。Theproduceperfurnacenowaverages90tonsa-week。TentonsofthisIattributetotheuseofrawpit-coal,andtheothertwentytonstotheuseofhotblast。”[PapersonIronandSteel,127。]Theproduceperfurnaceisnow200tonsa-weekandupwards。ThehotblastprocesswasafterwardsappliedtothemakingofironwiththeanthraciteorstonecoalofWales;forwhichapatentwastakenoutbyGeorgeCranein1836。Beforethehotblastwasintroduced,anthracitecoalwouldnotactasfuelintheblast-furnace。Whenputin,itmerelyhadtheeffectofputtingthefireout。Withtheaidofthehotblast,however,itnowprovestobeamostvaluablefuelinsmelting。