Emma throws a party
In honor of the Eltons, no less. Because it is expected of her. She invites the Westons and Mr Knightley, as well as Jane Fairfax, about whom she is feeling guilty after Mr Knightley's observations in the last chapter. (She first invites Harriet, hoping that Harriet will decline, which she does.)
Their party is increased by one Mr John Knightley, there to bring the two eldest of his boys for a visit, and decreased by one Mr Weston, who has business in London.
And we find out that Jane Fairfax makes a daily trip to the post office, and is quite adamant about going there, come hell or high water, and is equally adamant about not allowing anyone else to pick up her letters.
Curiouser and curiouser . . .
Meanwhile, Emma is a bit unhappy that Mr John Knightley is joining them. As her actual brother-in-law, he will take the seat at the bottom of the table (the opposite end from the top, of course, where Emma sits in her capacity as female head of household - Mr Woodhouse, we are told, doesn't like to have to preside over his own table). She would much prefer to look across the table at Mr Knightley.
Again, I say, "curiouser and curiouser . . . "
Let's talk about handwriting
What with that talk of letters, it's not unusual to mention handwriting. John Knightley says that Isabella's (his wife's) and Emma's is very much alike. Mr Knightley disagrees, saying that Emma's handwriting is stronger, with an implication that it is superior.
Emma mentions that Frank Churchill has nice handwriting (for a guy), and Mr Knightley decries it as small and feminine.
Is it just me, or is it possible to interpret Mr Knightley's comments about handwriting as interest in Emma and dislike for Frank?
Mrs Elton's notions of entertaining
Mrs Elton wants to make an impressive show with her entertaining. "Separate candles" means that she intends for each table to have its own candles, in addition to the sconces and any chandelier in the room - with candles being rather expensive, this is a form of display not usually bothered with. "Unbroken packs" is a reference to new packages of cards for each of the card tables - not necessary when people are playing parlor games for low stakes, although certainly common enough at high-stakes tables as a means of assuring that the deck has not been stacked.
Mrs Elton has come from Bath, which is a fairly busy metropolis, to Highbury, which is a small, rural town. Her shock at people not having ices (ice cream) at their parties, and her snootiness about the quality of the "rout-cakes" (small cakes served at evening entertainments), coupled with her being aghast that not everyone has two parlors, show that she is quite busy judging everyone - and generally finding them lacking.