( ( ( ( ( This ( was ( before ( ( ( the idea ) ( of molecules ) ) ( was developed ) ) ) ) ) , ) and ) ( we ( ( would now ) ( say ( that ( ( ( equal volumes ) ( of ( gas ( at ( the ( same ( ( temperature and ) pressure ) ) ) ) ) ) ) ( contain ( ( equal numbers ) ( of molecules ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (DT This)) (VP (VBD was) (SBAR (IN before) (S (NP (NP (DT the) (NN idea)) (PP (IN of) (NP (NNS molecules)))) (VP (VBD was) (VP (VBN developed))))))) (, ,) (CC and) (S (NP (PRP we)) (VP (MD would) (ADVP (RB now)) (VP (VB say) (SBAR (IN that) (S (NP (NP (JJ equal) (NNS volumes)) (PP (IN of) (NP (NP (NN gas)) (PP (IN at) (NP (DT the) (JJ same) (NN temperature) (CC and) (NN pressure)))))) (VP (VBP contain) (NP (NP (JJ equal) (NNS numbers)) (PP (IN of) (NP (NNS molecules)))))))))) (. .)))
This was before the idea of molecules was developed, and we would now say that equal volumes of gas at the same temperature and pressure contain equal numbers of molecules.
(ROOT (S (S (VP (VBG Reducing) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NP (NNS molecules)) (PP (IN in) (NP (DT a) (JJ rigid) (NN container)))))))) (VP (VBZ causes) (NP (NN pressure)) (S (VP (TO to) (VP (VB decrease))))) (. .)))