▁ 2 6 ▁April ▁ 1 7 7 5 ▁( comm only ▁referred ▁to ▁as ▁the ▁E aster ▁Mem oir ). ▁In ▁the ▁original ▁mem oir ▁Lav ois ier ▁showed ▁that ▁the ▁mer cur y ▁cal x ▁was ▁a ▁true ▁met all ic ▁cal x ▁in ▁that ▁it ▁could ▁be ▁reduced ▁with ▁char co al , ▁giving ▁off ▁Black ' s ▁fixed ▁air ▁in ▁the ▁process . ▁When ▁reduced ▁without ▁char co al , ▁it ▁gave ▁off ▁an ▁air ▁which ▁supported ▁resp iration ▁and ▁comb ust ion ▁in ▁an ▁en hanced ▁way . ▁He ▁concluded ▁that ▁this ▁was ▁just ▁a ▁pure ▁form ▁of ▁common ▁air ▁and ▁that ▁it ▁was ▁the ▁air ▁itself ▁" und iv ided , ▁without ▁alter ation , ▁without ▁decomposition " ▁which ▁combined ▁with ▁met als ▁on ▁calc ination . ▁ ▁After ▁returning ▁from ▁Paris , ▁Pri est ley ▁took ▁up ▁once ▁again ▁his ▁investigation ▁of ▁the ▁air ▁from ▁mer cur y ▁cal x . ▁His ▁results ▁now ▁showed ▁that ▁this ▁air ▁was ▁not ▁just ▁an ▁especially ▁pure ▁form ▁of ▁common ▁air ▁but ▁was ▁" five ▁or ▁six ▁times ▁better ▁than ▁common ▁air , ▁for ▁the ▁purpose ▁of ▁resp iration , ▁infl amm ation , ▁and ▁... ▁every ▁other ▁use ▁of ▁common ▁air ". ▁He ▁called ▁the ▁air ▁de ph log istic ated ▁air , ▁as ▁he ▁thought ▁it ▁was ▁common ▁air ▁dep riv ed ▁of ▁its ▁ph log ist on . ▁Since ▁it ▁was ▁therefore ▁in ▁a ▁state ▁to ▁abs orb ▁a ▁much ▁greater ▁quantity ▁of ▁ph log ist