( Then ( instruments ( ( will ( analyze ( ( the gas ) ( ( ( released ( by ( the heat ) ) ) , ) ( looking ( for ( ( ( water vapor ) and ) ( carbon dioxide ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (RB Then) (NP (NNS instruments)) (VP (MD will) (VP (VB analyze) (NP (NP (DT the) (NN gas)) (VP (VBN released) (PP (IN by) (NP (DT the) (NN heat))) (, ,) (S (VP (VBG looking) (PP (IN for) (NP (NP (NN water) (NN vapor)) (CC and) (NP (NN carbon) (NN dioxide)))))))))) (. .)))
Then instruments will analyze the gas released by the heat, looking for water vapor and carbon dioxide.
(ROOT (S (NP (NP (DT The) (NN combustion)) (PP (IN of) (NP (NN propane) (NN gas)))) (VP (VBZ produces) (NP (NP (NN carbon) (NN dioxide)) (CC and) (NP (NN water) (NN vapor)))) (. .)))