( He ( ( ( was best ) ( ( ( ( known ( for ( ( his discovery ) ( of ( ( the law ) ( of ( constant composition ) ) ) ) ) ) ) ( in 1799 ) ) , ) ( stating ( that ( ( in ( chemical reactions ) ) ( matter ( is ( neither ( ( created nor ) destroyed ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VBD was) (ADVP (RBS best)) (VP (VBN known) (PP (IN for) (NP (NP (PRP$ his) (NN discovery)) (PP (IN of) (NP (NP (DT the) (NN law)) (PP (IN of) (NP (JJ constant) (NN composition))))))) (PP (IN in) (NP (CD 1799))) (, ,) (S (VP (VBG stating) (SBAR (IN that) (S (PP (IN in) (NP (NN chemical) (NNS reactions))) (NP (NN matter)) (VP (VBZ is) (VP (RB neither) (VBN created) (CC nor) (VBN destroyed))))))))) (. .)))
He was best known for his discovery of the law of constant composition in 1799, stating that in chemical reactions matter is neither created nor destroyed.
(ROOT (S (NP (NNP Matter)) (VP (MD can) (RB not) (VP (VB be) (VP (VBN created) (CC or) (VBN destroyed) (PP (IN in) (NP (DT a) (NN chemical) (NN reaction)))))) (. .)))