See in text (Chapter XIV)
The Sphinx is a mythological beast known for killing anyone who cannot answer its riddle. Rochester’s simile suggests that he has an inflated ego and thinks very highly of himself. There is some discrepancy, though, between how Rochester regards himself and what Jane thinks of him—and she lets him know. Jane feels she can be more honest with him than she has with others in the past.
"all white as a glacier..."
See in text (Chapter XXXIII)
Brontë develops St. John as a foil for Rochester. Jane describes Rochester as having a “dark face” with a “heavy brow,” and he is often described as being full of “passion.” His brooding nature exudes a dark warmth that Jane is drawn to. St. John, on the other hand, is icy and “cool” like a “glacier.” Also note how Jane often described Rochester as being ugly, and just as often comments on St. John’s handsomeness. The contrast between them allows Rochester to emerge as the clear choice for Jane.