Mr. Martin’s office closed at one o’clock on Saturdays. He left a few minutes before that hour, having put John Lacey’s letter in his pocket and examined the mechanism of his automatic. Then he consumed a hasty lunch at a chophouse nearby, and walked down the street to Aldersgate Metropolitan station, where he took a ticket to Paddington. He emerged into Praed Street at about five minutes to two, and began to walk along that thoroughfare in the direction of Number 407.