a quarter before
six
exclaimed the doctor . `` Dinner at six , '' he added , with his politest emphasis , as she turned from him in disdainful silence , and slowly mounted the stairs to her own room . A clock of the noiseless sort -- incapable of offending irritable nerves -- was fixed in the wall , above the first-floor landing , at the Sanitarium . At the moment when the hands pointed to a quarter before six , the silence of the lonely upper regions was softly broken by the rustling of Miss Gwilt 's dress . She advanced along the corridor of the first floor -- paused at the covered apparatus fixed outside the room numbered Four -- listened for a moment -- and then unlocked the cover with the duplicate key . The open lid cast a shadow over the inside of the casing . All she saw at first was what she had seen already -- the jar , and the pipe and glass funnel inserted in the cork .