Itmaybementionedinpassing，thatwhileZincisfusibleat3degreesofWedgwood’spyrometer，Silverat22degrees，Copperat27degrees，andGoldat32degrees，CastIronisonlyfusibleat130degrees。TinoneoftheconstituentsoftheancientbronzeandLeadarefusibleatmuchlowerdegreesthanzinc。
Butitisprincipallyincombinationwithotherelementsthatironissovaluablewhencomparedwithothermetals。Thus，whencombinedwithcarbon，invaryingproportions，substancesareproduced，sodifferent，buteachsovaluable，thattheymightalmostberegardedinthelightofdistinctmetals，——such，forexample，ascast-iron，andcastandbarsteel；thevariousqualitiesofironenablingittobeusedforpurposessooppositeasasteelpenandarailroad，theneedleofamariner’scompassandanArmstronggun，asurgeon’slancetandasteamengine，themainspringofawatchandanironship，apairofscissorsandaNasmythhammer，alady’searringsandatubularbridge。
Thevarietyofpurposestowhichironisthuscapableofbeingapplied，rendersitofmoreusetomankindthanalltheothermetalscombined。Unlikeiron，goldisfoundpure，andinanalmostworkablestate；andatanerlyperiodinhistory，itseemstohavebeenmuchmoreplentifulthanironorsteel。Butgoldwasunsuitedforthepurposesoftools，andwouldserveforneitherasaw，achisel，anaxe，norasword；whilsttemperedsteelcouldanswerallthesepurposes。Hencewefindtheearlywarlikenationsmakingthebacksoftheirswordsofgoldorcopper，andeconomizingtheirsteeltoformthecuttingedge。ThisisillustratedbymanyancientScandinavianweaponsinthemuseumatCopenhagen，whichindicatethegreatestparsimonyintheuseofsteelataperiodwhenbothgoldandcopperappeartohavebeencomparativelyabundant。
Theknowledgeofsmeltingandworkinginiron，likemostotherarts，camefromtheEast。Ironwasespeciallyvaluedforpurposesofwar，ofwhichindeeditwasregardedasthesymbol，beingcalled”Mars”bytheRomans。*
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