Miss Jessel Timeline and Summary

Miss Jessel appears to the Governess (and possibly Flora) by the lake.
Prowling around the halls of the house late one night, the Governess sees Miss Jessel sitting miserably on the same staircase where she'd seen Quint earlier.
Miss Jessel appears in the schoolroom but doesn't speak. The Governess later tells Mrs. Grose that they conversed.
When the Governess and Mrs. Grose find Flora by the lake, the Governess sees Miss Jessel across the water again – she frantically tells the others to look at her. Mrs. Grose can't see her at all, while Flora either doesn't see her or denies that she sees her.