“I know of no better cure for shaken nerves than a _Cabana Cesare_,” he said cheerfully. “And without desiring to indulge in a boastful gesture, I can only tell you, Elk, that they don’t frighten me, any more than they frighten you. Frog is human, and has very human fears. Where is friend Broad?” “The American?” Dick nodded, and Elk, without a second’s hesitation, pulled the telephone toward him and gave a number. After a little delay, Broad’s voice answered him. “That you, Mr. Broad? What are you doing now?” asked Elk, in that caressing tone he adopted for telephone conversation. “Is that Elk? I’m just going out.” “Thought I saw you in Whitehall about five minutes ago,” said Elk. “Then you must have seen my double,” replied the other, “for I haven’t been out of my bath ten minutes. Do you want me?” “No, no,” cooed Elk. “Just wanted to know you were all right.” “Why, is anything wrong?” came the sharp question. “Everything’s fine,” said Elk untruthfully. “Perhaps you’ll call round and see me at my office one of these days—good-bye!” He pushed the telephone back, and raising his eyes to the ceiling, made a quick calculation. “From Whitehall to Cavendish Square takes four minutes in a good car,” he said. “So his being in the flat means nothing.” He pulled the telephone toward him again, and this time called Headquarters. “I want a man to shadow Mr. Joshua Broad, of Caverley House; not to leave him until eight o’clock to-night; to report to me.” When he had finished, he sat back in his chair and lit the long cigar that Dick had pressed upon him. “To-day is Tuesday,” he ruminated, “to-morrow’s Wednesday. Where do you propose to listen in, Captain Gordon? “At the Admiralty,” said Dick. “I have arranged with the First Lord to be in the instrument room at a quarter to three.” He bought the early editions of the evening newspapers, and was relieved to find that no reference had been made to the murder—as murder he believed it to be. Once, in the course of the day, looking out from his window on to Whitehall, he saw Elk walking along on the other side of the road, his umbrella hanging on his arm, his ancient derby hat at the back of his head, an untidy and unimposing figure. Then, an hour later, he saw him again, coming from the opposite direction. He wondered what particular business the detective was engaged in. He learnt, quite by accident, that Elk had made two visits to the Admiralty that day, but he did not discover the reason until they met later in the evening. “Don’t know much about wireless,” said Elk, “though I’m not one of those people who believe that, if God had intended us to use wireless, telegraph poles would have been born without wires. But it seems to me that I remember reading something about ‘directional.’ If you want to know where a wireless message is coming from, you listen in at two or three different points——”