Nine o'clock
He helped Fifi , upon her request , without spoken protest or censure . But he insisted on doing it after an iron-clad schedule : Absolute silence until nine o'clock ; then an interlude for the solving of difficulties ; absolute silence after that ; then at 9.45 a second interlude for the solving of the last difficulties of the night . The old rule of the dining-room , the _ Silence _ sign , had been necessarily suspended , but the young man enforced his schedule of hours far more strictly than the average railroad . `` Nine o'clock , '' he announced presently . `` Bring me your difficulties . '' Fifi 's brain was at low ebb to-night . She came around with several books , and he jabbed his pencil at her open Cicero with some contempt .