Mr Elton's presumption
Mr Elton presumes quite a bit in the course of this chapter, but for now, I'm talking about his conduct during the party at Randalls.
We are to understand that after dinner, Mr Woodhouse has immediately joined the ladies - cigars and port are not his cup of, er, tea, which is what he's imbibing in the parlor with the ladies. Mr Weston is quite happy to be entertaining the Knightley brothers and Mr Elton, so he's in no rush to rejoin the others; it is Mr Elton who turns up first, proceeding to sit between Emma and Mrs Weston, who had been having a bit of a tête-à-tête on a sofa.
Emma, who (Austen reminds us) has been thinking of Frank Churchill, has pretty much forgiven Mr Elton for being cavalier about Harriet's health earlier in the day - especially since he opens conversation by expressing concern for Harriet.
Emma's shock and indignation when it becomes clear that his mention of Harriet is merely a means of raising the issue of Emma's health is palpable. While endeavoring to claim some sort of right to guide her conduct, Elton is also (a) snubbing Harriet; (b) implicitly criticizing Emma for having visited her; (c) staking a claim to Emma - and doing so publicly by involving Mrs Weston in the conversation; (d) offering unsolicited (and unwelcome) advice. If you answered (e) ALL OF THE ABOVE, then award yourself a gold star.
A bit of etymology
We are told that Emma "had difficulty in behaving with temper", a word which here is used to mean "calmness of mind" or "a suitable balance or proportion of qualities". These days, we might say she is struggling to remain even-tempered, which is close to the meaning of temper as it existed in Austen's day. (To lose one's temper meant to lose one's cool (or evenness of mind), then as now; the word "temper" was not in and of itself a synonym for anger, as it is often used today - e.g., "She's got quite a temper.")
Mr Knightley, Man of Action
Now, those of you who remember my discussions of other Austen novels may realize that I've used the phrase "man of action" to describe Colonel Brandon in Sense & Sensibility, Captain Wentworth in Persuasion, Henry Tilney in Northanger Abbey, and Mr Darcy in Pride & Prejudice. Know what they all have in common? That's right - they are all heroes within their books. (Sorry, but Edward Ferrars does not cut it as a man of action, which pretty much suits Elinor just fine. And Lord knows that Edmund Bertram isn't a man of action either, although both of the Eds are also heroes; they also tend to come in last in polls of popular Austen heroes, with some of the "villains" faring better. But I digress.)
Mr Knightley, in the fine tradition of sexy Austen heroes (*wonders if Austen would cringe at that appellation*), is a man of action. Upon hearing that it is snowing outside, he (like everyone else) realizes that Mr Woodhouse and Isabella are likely to panic. While others fret and opine, he walks out the door and all the way down the "sweep" (a curved driveway in front of the house) to the Highbury road to determine how much snow is already on the ground. And he makes observations about how much snow is falling, and whether it looks to continue, and he talks with both of the coachmen to garner their opinions as well.
Mr Knightley's being a man of action bodes well for him as the likely successful love interest in this book. Mr Elton's continued presence on the couch does not.
When he comes in, Mr Knightley recommends that Emma and the rest of her party leave to go back to Hartfield, to which she agrees, and he then rings for the coaches. It shows (a) that he is thinking of what is best for not only Mr Woodhouse, but for Emma, who has to deal with her father's concerns and (b) that he is sensitive to others as well as full of good sense in general and (c) that he is, as we've already established, a man of action.
The Uncomfortable Coach Ride Home
In their haste to be gone, Mr Woodhouse and Isabella take Mr John Knightley with them, leaving Emma in the somewhat untenable position of being unchaperoned with Mr Elton inside a closed carriage. You will note that there's no mention of her being compromised as a result, although not for Mr Elton's lack of trying. [N.B. When Mr Elton is "actually making violent love to her", it means that he is declaring his love for her, accompanied by some hand-holding, and nothing more.]
Mr Elton: *does his best impression of Gene Kelly in the historical film nested in Singing in the Rain and/or of Gomez Addams* I love you, I love you, I love you.
Emma: O_o Are you off your rocker? You love Harriet, not me.
Mr Elton: WHAT? No effing way. It is you that I have the hots for, you
Emma: O_o Are you off your rocker? I'm sure you love Harriet, not me.
Mr Elton: Um, NO. As if. I only ever thought of her as your friend. I have been assiduously courting you for weeks, AND YOU HAVE BEEN ENCOURAGING ME!
Emma: Yeah, well I only ever thought of you as Harriet's possible husband. Sheesh.
Mr Elton: Me? Marry Miss Smith? Are you off your rocker? I can do much better than a Miss Smith. She seems nice enough and I wish her well. I'm sure there are some mean who don't mind that . . . well, "Every body has their level: but as for myself, I am not, I think, quite so much at a loss. I need not so totally despair of an equal alliance, as to be addressing myself to Miss Smith!" And you most certainly did encourage me.
Emma: Did not.
Mr Elton: Did too. *seethes*
Emma: Ah. Here we are at the vicarage.
Mr Elton: *growls at her*
When Emma gets home, she finds that things there have sorted themselves out:
Mr. John Knightley, ashamed of his ill-humour, was now all kindness and attention; and so particularly solicitous for the comfort of her father, as to seem — if not quite ready to join him in a basin of gruel — perfectly sensible of its being exceedingly wholesome; and the day was concluding in peace and comfort to all their little party, except herself. —But her mind had never been in such perturbation; and it needed a very strong effort to appear attentive and cheerful till the usual hour of separating allowed her the relief of quiet reflection.