( ( ( The ( easiest experiment ) ) ( that ( could ( be ( conducted ( in ( ( the ( nineteenth century ) ) ( using ( sub-atomic particles ) ) ) ) ) ) ) ) ) ( ( was ( using ( ( ( electron beams ) , ) ( ( a ( focussed flow ) ) ( of ( ( excited electrons ) ( ( ( emitted ( from ( ( a ( heated ( metal source ) ) ) ( accelerated ( by ( electric fields ) ) ) ) ) ) and ) ( tuned ( by ( magnetic ones ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJS easiest) (NN experiment)) (SBAR (WHNP (WDT that)) (S (VP (MD could) (VP (VB be) (VP (VBN conducted) (PP (IN in) (NP (NP (DT the) (JJ nineteenth) (NN century)) (VP (VBG using) (NP (JJ sub-atomic) (NNS particles))))))))))) (VP (VBD was) (VP (VBG using) (NP (NP (NN electron) (NNS beams)) (, ,) (NP (NP (DT a) (JJ focussed) (NN flow)) (PP (IN of) (NP (NP (VBN excited) (NNS electrons)) (UCP (VP (VBN emitted) (PP (IN from) (NP (NP (DT a) (JJ heated) (NN metal) (NN source)) (VP (VBN accelerated) (PP (IN by) (NP (JJ electric) (NNS fields))))))) (CC and) (ADJP (VBN tuned) (PP (IN by) (NP (JJ magnetic) (NNS ones))))))))))) (. .)))
The easiest experiment that could be conducted in the nineteenth century using sub-atomic particles was using electron beams, a focussed flow of excited electrons emitted from a heated metal source accelerated by electric fields and tuned by magnetic ones.
(ROOT (S (NP (NNP Metal)) (VP (VBZ conducts) (NP (NP (NN heat) (CC and) (NN electricity)) (ADVP (RB so)) (PP (RB well) (RB because) (IN of) (NP (JJ free) (VBG flowing) (NNS electrons))))) (. .)))