Here's a link to an old post of mine at L+T, which covers this question, I hope, Emmy.

I've also done a little more "digging" : though at first, in the early to mid 18th century at balls in Bath, the minuet was danced by individual couples in order of prescedence, and the country dances could not begin until everyone had thus danced , in time the minuets were not danced singly by couples, but by lots of couples at one time,in what was termed the " Long Minuet",( in order to allow the balls to proceed at a greater pace considering all the people who wished to dance!)

Look at this from John Eglin's book ,page 242.

The minuet , that communal sacrament witnessed as compliantly as the elevation of the host on the other side of the confessional table also fell vitim to crowds and fashions.

The traditional dance( danced invidiually by couples in order of presecedence-JW) was abandoned for the " long minuet" in which several couples danced at the same time, meaning that more members of the Company could participate and also that the ordeal would be over sooner.

The dress code also relaxed considerably. The dancers shown in Henry Bunbury's engraving(see below ) wear the fashionable dress of teh 1780s.Ultimately even the long minuet dissapppeared, although John King ,Master of Ceremonies in Jane Austen's day, tried unsucessfully to revive it.

Even more gradually, the Assembly Rooms themselves fell out of fashion...Jane Austen had Catherine Moreland wade through an uncomfortably crowded assembly room in Northanger Abbey ; in Persuasion , the Elliot sisters eschew the rooms altogether

This is teh Bunbury illustration to which John Eglin refers.