General Besserley’s Second Puzzle Box

General Besserley sat before his writing-table, drawn close up to the wide-flung windows of his summer-house, his pen clasped in his idle fingers, his eyes wandering though a tangle of drooping roses and clematis beyond the gardens below to where a car was crawling up the mountain road. He leaned a little sideways and touched a bell. In a few moments a white-coated butler opened the door and approached the table.