] He has a Y chromosome and he's interested in Isabella.

LOL! Yep, that's plenty enough reason for Isabella to flirt. To tell you the truth, I don't think she really requires much interest.

] ...but honestly I think she'd flirt with a street sweeper if he paid her any attention.

LOL! So you think she's more interested in the attention of the moment them, than she is angling for something of more substance? (Namely, a proposal)

] What I'm having trouble figuring out is why she is flirting so openly around Catherine? Either she thinks Catherine is so dense that she won't notice, or she wants this news to get back to JM.

I thought it was something quite different. I thought that Isabella wasn't thinking of Catherine at all, but she wasn't going to let her presence prevent her from flirting with the Captain when an opportunity presented itself.

] Since I don't think JM would be allowed to break off the engagement, he probably would have to fight a duel with the Capt. Is this what IT is angling for?

No, it would hardly be right for JM to break off the engagement. He's made a promise and as a gentleman he must keep it. But, ooh...what a picture you paint of Isabella! ;-) Angling for a duel?! Do you really think she'd try to get James killed just to get out of the engagement?! That is terrible indeed...quite as bad as anything Catherine has read. Isabella is a little minx and I think her capable of quite a lot that is naughty, but nothing so bad as that. :-)

] I think Henry needs to get busy and marry Catherine before she gets hurt. :)

Hmmm. Much as I'd like to see Henry and Catherine married, I don't see how this will prevent her from getting hurt on her brother's behalf. If her brother is hurt by Isabella, I doubt distance and even matrimony will be of much consolation. :-)