( ( ( ( ( Tilting ( is ( stopped ( when ( ( the material ) ( begins ( to ( slide ( in bulk ) ) ) ) ) ) ) ) ) , ) and ) ( ( ( the angle ) ( of ( the tilt ) ) ) ( is measured ) ) ) . )
(ROOT (S (S (NP (NNP Tilting)) (VP (VBZ is) (VP (VBN stopped) (SBAR (WHADVP (WRB when)) (S (NP (DT the) (NN material)) (VP (VBZ begins) (S (VP (TO to) (VP (VB slide) (PP (IN in) (NP (NN bulk)))))))))))) (, ,) (CC and) (S (NP (NP (DT the) (NN angle)) (PP (IN of) (NP (DT the) (NN tilt)))) (VP (VBZ is) (VP (VBN measured)))) (. .)))
Tilting is stopped when the material begins to slide in bulk, and the angle of the tilt is measured.
(ROOT (S (NP (NP (NNP Instruments)) (SBAR (WHNP (WDT that)) (S (VP (VB measure) (NP (NP (DT the) (NN angle)) (PP (IN of) (NP (NP (DT the) (NN slope)) (PP (IN of) (NP (DT a) (NN volcano)))))))))) (VP (VBP are) (VP (VBN called) (NP (NN tilt) (NNS meters)))) (. .)))