At the end of ch.17, Mr. Elliot is described this way:

Mr. Elliot was too generally agreeable. Various as were the tempers in her father's house, he pleased them all. He endured too well, stood too well with everybody. He had spoken to [Anne] with some degree of openness of Mrs. Clay; had appeared completely to see what Mrs. Clay was about, and to hold her in contempt; and yet Mrs. Clay found him as agreeable as anybody.

This suddenly made me wonder if Mrs. Clay is aware how *Anne* feels about her. Anne is pretty reserved and self-controlled too, and I'm sure she's always polite to Mrs. Clay when they're together, so perhaps it's just a touch hypocritical to complain that Mr. Elliot behaves so differently to Mrs. Clay's face than he does behind her back? (Just speculating... ;-)

BTW, the above description of Mr. Elliot made me think of Mr. Knightley and Emma's discussion about what Frank Churchill might be like:

Emma: "My idea of him is, that he can adapt his conversation to the taste of every body, and has the power as well as the wish of being universally agreeable. To you, he will talk of farming; to me, of drawing or music; and so on to every body, having that general information on all subjects which will enable him to follow the lead, or take the lead, just as propriety may require, and to speak extremely well on each; that is my idea of him."