( It ( ( was ( known ( ( ( ( that ( ( the conductor ) ( should ( ( ( be ( of copper ) ) , ) ( ( possessing ( a ( high conductivity ) ) ) ( for ( the ( electric current ) ) ) ) ) ) ) ) , ) and ) ( that ( ( ( its ( insulating jacket ) ) ( of gutta-percha ) ) ( should ( ( offer ( a ( great resistance ) ) ) ( to ( ( the leakage ) ( of ( the current ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBD was) (VP (VBN known) (SBAR (SBAR (IN that) (S (NP (DT the) (NN conductor)) (VP (MD should) (VP (VB be) (PP (IN of) (NP (NN copper))) (, ,) (S (VP (VBG possessing) (NP (DT a) (JJ high) (NN conductivity)) (PP (IN for) (NP (DT the) (JJ electric) (NN current))))))))) (, ,) (CC and) (SBAR (IN that) (S (NP (NP (PRP$ its) (JJ insulating) (NN jacket)) (PP (IN of) (NP (NN gutta-percha)))) (VP (MD should) (VP (VB offer) (NP (DT a) (JJ great) (NN resistance)) (PP (TO to) (NP (NP (DT the) (NN leakage)) (PP (IN of) (NP (DT the) (JJ current)))))))))))) (. .)))
It was known that the conductor should be of copper, possessing a high conductivity for the electric current, and that its insulating jacket of gutta-percha should offer a great resistance to the leakage of the current.
(ROOT (S (NP (PRP You)) (VP (VBP call) (NP (NP (NNS materials)) (SBAR (WHNP (WDT that)) (S (VP (VBP have) (NP (JJ high) (NN resistance)) (PP (TO to) (NP (JJ electric) (JJ current) (JJ electric) (NNS insulators)))))))) (. .)))