( ( ( MANOMETER -- ) ( Instrument ( used ( for ( measuring ( ( the pressure ) ( of gases ) ) ) ) ) ) ) . )
(ROOT (NP (NP (NNP MANOMETER)) (: --) (NP (NP (NNP Instrument)) (VP (VBN used) (PP (IN for) (S (VP (VBG measuring) (NP (NP (DT the) (NN pressure)) (PP (IN of) (NP (NNS gases))))))))) (. .)))
MANOMETER -- Instrument used for measuring the pressure of gases.
(ROOT (S (NP (NP (DT The) (NN pressure)) (PP (IN of) (NP (NP (DT a) (NN sample)) (PP (IN of) (NP (NN gas)))))) (VP (VBZ is) (VP (VBN measured) (PP (IN with) (NP (DT an) (JJ open-end) (NN manometer))))) (. .)))