1 7 8 4 ), ▁and ▁immediately ▁recognized ▁water ▁as ▁the ▁ox ide ▁of ▁a ▁hydro elect ric ▁gas . ▁ ▁In ▁co operation ▁with ▁math ematic ian ▁Pierre ▁Simon ▁de ▁Lap lace , ▁Lav ois ier ▁synth es ized ▁water ▁by ▁burning ▁j ets ▁of ▁hydro gen ▁and ▁o xygen ▁in ▁a ▁bell ▁jar ▁over ▁mer cur y . ▁The ▁quant itative ▁results ▁were ▁good ▁enough ▁to ▁support ▁the ▁cont ention ▁that ▁water ▁was ▁not ▁an ▁element , ▁as ▁had ▁been ▁thought ▁for ▁over ▁ 2 , 0 0 0 ▁years , ▁but ▁a ▁comp ound ▁of ▁two ▁g ases , ▁hydro gen ▁and ▁o xygen . ▁The ▁interpretation ▁of ▁water ▁as ▁a ▁comp ound ▁explained ▁the ▁infl amm able ▁air ▁generated ▁from ▁dissol ving ▁met als ▁in ▁ac ids ▁( h ydro gen ▁produced ▁when ▁water ▁decom poses ) ▁and ▁the ▁reduction ▁of ▁cal ces ▁by ▁infl amm able ▁air ▁( a ▁combination ▁of ▁gas ▁from ▁cal x ▁with ▁o xygen ▁to ▁form ▁water ). ▁ ▁Despite ▁these ▁experiments , ▁Lav ois ier ' s ▁anti ph log istic ▁approach ▁remained ▁un accept ed ▁by ▁many ▁other ▁chem ists . ▁Lav ois ier ▁labor ed ▁to ▁provide ▁definit ive ▁proof ▁of ▁the ▁composition ▁of ▁water , ▁attempting ▁to ▁use ▁this ▁in ▁support ▁of ▁his ▁theory . ▁Working ▁with ▁Jean - B apt iste ▁Me us nier , ▁Lav ois ier ▁passed ▁water ▁through ▁a ▁red - hot ▁iron ▁gun ▁bar rel , ▁allowing ▁the ▁o xygen ▁to ▁form ▁an ▁ox ide