We get a house party scene, as Jane watches Rochester and his guests play charades (and act out a sham marriage - what foreshadowing!) and generally banter.
Which means, of course, that she's watching Blanche and Rochester, fairly sure that a marriage is in the works -- even if Blanche clearly doesn't know Mr. R. as well as Jane does:
"Because, when she failed, I saw how she might have succeeded. Arrows that continually glanced off from Mr. Rochester’s breast and fell harmless at his feet, might, I knew, if shot by a surer hand, have quivered keen in his proud heart—have called love into his stern eye, and softness into his sardonic face; or, better still, without weapons a silent conquest might have been won."We're very much in Jane's head here, as she ponders the nature of interpersonal relations, until a new character makes an appearance. Meet Mr. Mason:
the new-comer was called Mr. Mason; then I learned that he was but just arrived in England, and that he came from some hot country: which was the reason, doubtless, his face was so sallow, and that he sat so near the hearth, and wore a surtout in the houseAnd then there's one more addition to the house: a gypsy shows up, and offers to tell the young ladies' fortunes. Blanche, of course, is first. Jane stays out of the way until the gypsy specifically asks for her - which leads us into Chapter 19.