For trappings and inventions in motion we have his tapping shoe and the busy clock pendulum.

Because this scene is so powerful the photoplay is described in this chapter rather than any other, though the application is more spiritual than literal.

The half-mad boy begins to divulge that he thinks that the habitual ticking of the clock is satanically timed to the beating of the dead man's heart.

Here more unearthliness hovers round a pendulum than any merely mechanical trick-movements could impart.

Then the merest commonplace of the detective tapping his pencil in the same time--the boy trying in vain to ignore it--increases the strain, till the audience has well-nigh the hallucinations of the victim.