As a first-time all-the-way-to-the-end reader of NA ;-), I was suprised to see Isabella Thorpe engaged to James Morland so quickly. Now, I'm surprised to find that their engagement is off. (How long did the thing last, about a month?) Whatever else, that Isabella certainly is a fast worker, and James, at least, seems convinced that she is now engaged to Captain Tilney, though his siblings are not. I thought that Isabella was flirting with the Captain, but that she would hold onto the security of James.
(I love the last line of ch.25: "Catherine, by some chance or other, found her spirits so very much relieved by this conversation that she could not regret her being led on, though *so unaccountably*, to mention the circumstance which had produced it.")