He stood up abruptly and started to pace up and down in the smoking room, first slowly, then faster and faster. Everyone looked at him with some bewilderment, but nobody was more alarmed than I, for I noticed how his pacing up and down, vehement though it was, always measured the same length; it was as if he, in the middle of this empty room, had come up against an invisible cupboard which made him turn back.
