A few things in the GR have been puzzling me about dance etiquette.

John Thorpe engages Catherine as a partner for the dance in Chapter 8. Is that for a specific dance (ie the first of the evening?... or her first upon her arrival?). Because if she's left sitting for all appearances like a wallflower, what's to stop her from accepting Henry's offer since her partner's a no-show? Because if I understand correctly, the dance is already underway. Is she obliged to wait for him even when JT's standing her up? Perhaps that's because it's an engagement for the set (ie two consecutive dances if I remember my L&T reading correctly), so there's still the hope of him showing up.

The other thing that had me puzzling was the seeming necessity of Mrs. Hughes asking Catherine to "let in" Miss Tilney next to her at the dance. Did a new party joining into the dance have to be introduced in? Did Catherine & JT have to be intro'd in earlier when they finally joined?

Later Isabella seems to use the "set" in terms of the how the dancers are grouped together, rather than in terms of a two-dance set, it seems.

Any experts out there to shed some light?

I did do some digging around in the archives and found this interesting post which, although pertains specifically to 1816, you all might find of interest.