And yet, had she been in the habit of watching her own mental states, she would have discovered that Stephen White was very much in her thoughts; that she had come to wondering why she never met him in her walks; and, what was still more significant, to mistaking other men for him, at a distance.

This is one of the oddest tricks of a brain preoccupied with the image of one human being.

One would think that it would make the eye clearer-sighted, well-nigh infallible, in the recognition of the loved form.

Not at all.
Waiting for her lover to appear, a woman will stand wearily watching at a window, and think fifty times in sixty minutes that she sees him coming.
Tall men, short men, dark men, light men; men with Spanish cloaks, and men in surtouts,--all wear, at a little distance, a tantalizing likeness to the one whom they in no wise resemble.
After such a watching as this, the very eye becomes disordered, as after looking at a bright color it sees a spectrum of a totally different tint; and, when the long looked-for person appears, he himself looks unnatural at first, and strange.

How well many women know this curious fact in love's optics! I doubt if men ever watch long enough, and longingly enough, for a woman's coming, to be so familiar with the phenomenon.
Stephen White, however, had more than once during these four weeks quickened his pace to overtake some slender figure clad in black, never doubting that it was Mercy Philbrick, until he came so near that his eyes were forced to tell him the truth.