I wonder if anyone else who is reading along was struck by the curious use of couples moving in and out as in a dance in this chapter. There is Fanny sitting on a bench, and next to her are Mary and Edmund. They go off to be replaced by Henry Crawford, Maria, and Rushworth. He is sent off for the key, and they disappear beyond the fence. Along comes Julia, irritated; she too cannot sit still and must form a member of the chase. The Rushworth with said key, at first too proud to follow the others, but then, with Fanny's encouragement anxious too. The whole scene reminded me of a "mistakes of the night" Restoration comedy or some Congreve play, except the comedy is anything but merry. The scenery is lovely, the people (all but Fanny and Edmund) wholly unloving.
One of the elements that makes this novel for me such an 18th century one is its roots in Restoration and 18th century drama. One of the older studies of 18th century drama--written at a time when a desideratum was readability, lucidity, and even grace, is by John Harrington Smith. In The Gay Couple in Restoration Comedy. he says there are often 2 kinds of couples in Restoration comedy: , the gay and witty couple, where the man is often promiscuous and the lady not too worried about such things; and 2) the serious, sober couple, the lady of which is especially virtuous. The earliest manifestation of these are Beatrice and Benedick (for gay and witty) and Hero and Leander (for sober and serious) in SHakespeare's MAAN. But the type is fully developed by Etherege, Congreve, &c where the gay and witty become "top" couple, with serious and sober definitely in the grayer background. Smith's idea is that the witty gay couple declines in influence and admiration over the course of time until by the second decade of the 18th century the "top" couple is now not only serious and sober, but their example influences everyone else, witty or otherwise, to reform and transform themselves into hopeful clones of the serious pair. From Richard Steele & Colley Cibber, & Fielding to the time of Goldsmith and Sheridan this tradition controls the presentation of the heroes and heroines of plays.
If we turn to Mansfield Park we see these pairs are still there, but seen very deeply: Edmund and Fanny are the old sober serious pair become top couple, Mary and Henry are the old witty gay pair who are, however, in Austen, not reformable because Austen knows better. Their gaiety is in fact the result of a hollowness and unfeelingness towards others from within--at Sotherton this is especially true of Crawford's behavior.
Seen through this paradigm Tom and Maria Bertram are characters who think they are witty, but are anything but. Julia has some traces of depths of feeling and seriousness. Rushworth is the clown.