midnight
Good-bye . '' A porter protested . The Englishman made for the station-master 's office . Fifty minutes later , he jumped into a train which brought him back to Paris a little before midnight . He ran across the station into the refreshment room , went out by the other door and sprang into a cab : `` Drive to the Rue Clapeyron . '' After making sure that he was not being followed , he stopped the cab at the commencement of the street and began to make a careful examination of the house in which Maître Detinan lived and of the two adjoining houses . He paced off certain distances and noted the measurements in his memorandum book : `` Now drive to the Avenue Henri-Martin . ''