At seven o'clock on a fine evening in April the gas had just been lighted in a room on the first floor of a house in York Road, Lambeth. A man, recently washed and brushed, stood on the hearthrug before a pier glass, arranging a white necktie, part of his evening dress. He was about thirty, well grown, and fully developed muscularly. There was no cloud of vice or trouble upon him: he was concentrated and calm, making no tentative movements of any sort (even a white tie did not puzzle him into fumbling), but acting with a certainty of aim and consequent economy of force, dreadful to the irresolute. His face was brown, but his auburn hair classed him as a fair man.