Sentence:  Screwed at its axis against the side, a swinging lamp slightly oscillates in Jonah's room; and the ship, heeling over towards the wharf with the weight of the last bales received, the lamp, flame and all, though in slight motion, still maintains a permanent <WSD>obliquity</WSD> with reference to the room; though, in truth, infallibly straight itself, it but made obvious the false, lying levels among which it hung. 
Meaning of the word marked with <WSD> tags:  The quality of being oblique in direction, deviating from the horizontal or vertical; (or) the angle created by such a deviation. (from 15th c.)