When, on Oct. 25, Louisa says:

There is to be a large ball on board the Acbar this evening. (O25 )
it can be concluded that it is to celebrate the Anniversary of the Accession of George III.

And when on Sept. 12 she says:

There was to be some fireworks performed tonight; but the rain, I suppose, will put a stop to it. (S12 )
it is likely in celebration of the capture of Napoleon, of whom with some indignation Louisa spoke a week earlier:
There is news of Bonaparte's being taken. --I hope it is true. There is no punishment too great for such a wretch. -- How many lives has been sacrificed for his ambition. (S4 )
Similarly, the ball at Mount Edward on Dec. 27 is evidently in celebration of Christmas even though Christmas Day itself appears to have been very quietly observed; and the presence at Colin Grove on Dec. 31 of "lots of young beaus" who "came to inquire after the ladies' health"--as well as the subsequent partying at Mrs. Allen's--may be taken as evidence of the celebration of New Year's .