Edmund Bertram gave a good description of such an evening in Chapter 13 of Mansfield Park;

“Nay,” said Edmund, who began to listen with alarm. “Let us do nothing by halves. If we are to act, let it be in a theatre completely fitted up with pit, boxes, and gallery, and let us have a play entire from beginning to end; so as it be a German play, no matter what, with a good tricking, shifting afterpiece, and a figure dance, and a hornpipe, and a song between the acts. If we do not outdo Ecclesford, we do nothing.”

I rather like to think that JA had heard of this odd combination of acts – (see below)

If you attended a night at the Theatre Royal or Covent Garden, what could you expect to see? The answer is – quite a lot for your money.

As the audience was gathering- or rather rushing into their seats, the orchestra would be playing various selections of music.
This it did for two or sometimes three, separate intervals over a period of about half an hour. The beginning of the music was preceded always by the ringing of the prompter’s bell. When the music ended the bell was rung (vigorously,) again.

This gave the audience a cue that the performance was about to begin (note, the house lights could not be switched off to warn the audience of the impending performance).

The orchestra sat in a sunken pit between the audience and the proscenium arch.

From the arch would be hung the curtain – made of green baize.

Jane Austen certainly got her facts right when it came to recreating an authentic late Georgian/early Regency theatrical performance.

Do you recall the curtain at the Mansfield Park theatricals?

“An enormous roll of green baize had arrived from Northampton, and been cut out by Mrs. Norris (with a saving by her good management of full three quarters of a yard), and was actually forming into a curtain by the housemaids.”
Chapter 14

And;

“We must have a curtain,” said Tom Bertram; “a few yards of green baize for a curtain, and perhaps that may be enough.”Chapter 13. (See earlier post linked here on green baize.)

The prompter then rang his bell once more and the beginning of entertainment proper began.

If there was to be a prologue the curtain did not rise, until after the prologue had been spoken.

Some prologues became well known. Audiences would demand that a particular prologue (and indeed epilogue) would be said whether it was announced on the playbill or not. Mrs Siddons was renowned for speaking them very beautifully. Thomas King who often said the prologue to David Garrick’s Bon Ton (a play performed by the Austen family at Steventon); this was considered to be one of the high points of his career! (See Prologues and epilogues of the 18th Century, by Mary Knapp (1956).)

Then came the mainpiece -a five-act play.

After pieces, usually two act farces, followed, but it was often considered that this was not enough for the public.

The theatre management usually inserted some musical diversion or dancing between the two pieces.

Perhaps the most famous (or infamous) examples of this incongruous custom was the performance of “A Hornpipe in Wooden Shoes” after a performance of Hamlet. See Charles Beecher Hogan (the London Stage (1770-1800). Unfortunately no date is given in Prof. Hogan’s book for this “famous performance” but I feel sure it would have appealed to JA sense of the ridiculous. She must surely have heard of it (or performances like it) living in such a theatrically obsessed family, which lead her to make Edmund Bertram pour forth his sarcastic speech quoted above.

I have found one dated playbill for such an incongruous evening.

Covent Garden Monday 24th October 1796;

Othello Moor of Venice (mainpiece)

Also

Afterpiece Harlequin’s Treasure

With a view of the Deserts of Arabia

“Come Pass the Box-to be sung,” composed by Arne

Prison scene with a Hornpipe danced in fetters by Blurton.

The audience of the period generally saw nothing unusual or odd about this amalgam of unconnected pieces. However the fact the Edmund Bertram (or JA) made note of the absurdity of it all indicates to me at least the possibility that not everyone was enamored of such billings.

They certainly appreciated variety.

They also had to have stamina.

The theatre Museum in London has calculated that most performances totaled 4 hours. But there were notable exceptions. The performance of Hamlet at Drury Lane on 8th March 1784 took 4 hours. After, that came a ballet “The Return of the Hunters”, which lasted 30 minutes. Then came a new two act musical farce, “The Double Disguise” still to follow.

A long night to sit on a wooden bench with no back to it. IMHO.

Wendeborn in his book “A View of England” vol. II p251-52 stated;“It has been frequently and perhaps not unjustly objected to English theatrical entertainments, that they last too long; and that the spectators, at least those in the pit and in the galleries i.e. those who most often entered the theatre when the doors were first
opened] are obliged to remain in their places above 4 hours together. It is therefore the more necessary to keep the stage, during that time, always busy and that the dramatic writers should introduce as much variety in their plays and multiply the situations in them as much as possible. It is indeed very visible in the theatres of London that the eyes and thoughts of the generality of spectators wander about much; that they begin to yawn and forget the play. For this reason good humour is to be kept between the acts by means of songs, dances, processions and things of that kind have observed that this was necessary even in many of Shakespeare’s plays to prevent drowsiness among the audience.”