What purpose does miss Havisham say the table will serve?

From the text:

"On the broad landing between Miss Havisham's own room and that other room in which the long table was laid out, I saw a garden-chair,--a light chair on wheels, that you pushed from behind. It had been placed there since my last visit, and I entered, that same day, on a regular occupation of pushing Miss Havisham in this chair (when she was tired of walking with her hand upon my shoulder) round her own room, and across the landing, and round the other room. Over and over and over again, we would make these journeys, and sometimes they would last as long as three hours at a stretch. I insensibly fall into a general mention of these journeys as numerous, because it was at once settled that I should return every alternate day at noon for these purposes, and because I am now going to sum up a period of at least eight or ten months."