Hisadditionstothesteam-enginewereofgreatpracticalvalue，oneofwhich，theself-actingapparatusattachedtotheboilerforthepurposeofregulatingtheintensityoffireunderit，andconsequentlytheproductionofsteam，isstillingeneraluse。Thiswasinventedbyhimasearlyas1799。HealsosubsequentlyinventedtheDslidevalve，oratleastgreatlyimprovedit，whileheaddedtothepoweroftheair-pump，andgaveanewarrangementtotheotherparts，withaviewtothesimplificationofthepowersoftheengine。
TomaketheDvalveworkefficiently，itwasfoundnecessarytoformtwoperfectlyplanesurfaces，toproducewhichheinventedhisplaningmachine。Hewasalsothefirsttoadoptthepracticeofplacingthepistoninahorizontalpositioninthecommoncondensingengine。Amonghisothermodificationsinthesteam-engine，washisimprovementofthelocomotiveasinventedbyTrevithick；anditoughttoberememberedtohishonourthathemadethefirstlocomotivethatregularlyworkeduponanyrailway。
ThiswastheengineerectedbyhimforBlenkinsop，toworktheMiddletoncollieryrailwaynearLeeds，onwhichitbegantorunin1812，andcontinuedinregularuseformanyyears。Inthisengineheintroducedthedoublecylinder——Trevithick’senginebeingprovidedwithonlyonecylinder，thedefectsofwhichweresupplementedbytheadditionofafly-wheeltocarrythecrankoverthedeadpoints。
ButMatthewMurray’smostimportantinventions，consideredintheireffectsonmanufacturingindustry，werethoseconnectedwiththemachineryforhecklingandspinningflax，whichheverygreatlyimproved。HishecklingmachineobtainedforhimtheprizeofthegoldmedaloftheSocietyofArts；andthisaswellashismachineforwetflax-spinningbymeansofspongeweightsprovedofthegreatestpracticalvalue。Atthetimewhentheseinventionsweremadetheflaxtradewasonthepointofexpiring，thespinnersbeingunabletoproduceyarntoaprofit；andtheiralmostimmediateeffectwastoreducethecostofproduction，toimproveimmenselythequalityofthemanufacture，andtoestablishtheBritishlinentradeonasolidfoundation。Theproductionofflax-machinerybecameanimportantbranchofmanufactureatLeeds，largequantitiesbeingmadeforuseathomeaswellasforexportation，givingemploymenttoanincreasingnumberofhighlyskilledmechanics。*
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