( ( This belief ) ( ( was ( ( based ( on ( the ( observable fact ) ) ) ) ( that ( mercury ( was ( ( the ( only ( metal liquid ) ) ) ( at ( room temperature ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This) (NN belief)) (VP (VBD was) (VP (VBN based) (PP (IN on) (NP (DT the) (JJ observable) (NN fact))) (SBAR (IN that) (S (NP (NN mercury)) (VP (VBD was) (NP (NP (DT the) (JJ only) (NN metal) (NN liquid)) (PP (IN at) (NP (NN room) (NN temperature))))))))) (. .)))
This belief was based on the observable fact that mercury was the only metal liquid at room temperature.
(ROOT (S (NP (NNP Mercury)) (VP (VBZ is) (RB not) (NP (DT a) (JJ solid) (ADJP (RB even) (PP (IN at) (NP (NN room)))) (NN temperature))) (. .)))