Toilet sacrifices to the goddess of grace
Trollope states that Mr. Toogood is allowed into the drawing room of Mr. and Mrs. Walker even though he had made “no toilet sacrifices to the goddess of grace”–or, in other words, prepared his appearance especially for a social visit. The Graces were three mythological goddesses who embodied grace and charm. [KD & RR 2006]
Sources: Cassell’s Dictionary of Classical Mythology.
There’s many a slip twixt the cup and the lip
Trollope uses this saying throughout his novels, especially (but not exclusively) in regard to engagements. It basically means that many things can happen to obstruct a seemingly sure thing. Miss Prettyman reminds her sister that it is still possible that Major Grantly and Grace Crawley won’t get married. For the connection to Classics, see the commentary for Chapter 24 of Barchester Towers. [KD 2006]