"Sounded like a ghost, didn't it?" he asked. "Ghosts don't rattle papers," snapped Preston. "At least self-respecting ones don't, and the other kind haven't any right to run around loose. So suppose we try to trap this one." "Trap it? How?" "Like you'd trap a mouse--only with a different kind of bait. Is there any milk in the house?" "Possibly--I don't know." "Go down to the refrigerator and find out, will you? I'll stay here until you return. And bring a saucer with you." A few moments later, when the chief returned, bearing a bottle of milk and a saucer, he found Preston still standing beside the table, his eyes fixed upon a corner of the room from which the sound of rattling paper had come. "Now all we need is a box," said the Postal operative. "I saw one out in the hall that will suit our purposes excellently." Securing the box, he cut three long and narrow strips from the sides, notched them and fitted them together in a rough replica of the figure 4, with the lower point of the upright stick resting on the floor beside the saucer of milk and the wooden box poised precariously at the junction of the upright and the slanting stick. "A figure-four trap, eh?" queried the chief. "What do you expect to catch?" "A mixture of a ghost and the figure of Justice," was Preston's enigmatic reply. "Come on--we'll lock the door and return later to see if the trap has sprung. Meanwhile, I'll send some wires to Sacramento, San Francisco, and other points throughout the state." The telegram, of which he gave a copy to the local chief of police, "in order to save the expense of sending it," read: Wire immediately if you know anything of recent arrival from Africa--probably American or English--who landed within past three days. Wanted in connection with Montgomery murder. The message to San Francisco ended with the phrase "Watch outgoing boats closely," and that to Sacramento "Was in your city yesterday." Hardly an hour later the phone rang and a voice from police headquarters in Sacramento asked to speak to "Postal Inspector Preston." "Just got your wire," said the voice, "and I think we've got your man. Picked him up on the street last night, unconscious. Hospital people say he's suffering from poisoning of some kind and don't expect him to live. Keeps raving about diamonds and some one he calls 'Marsh.' Papers on him show he came into San Francisco two days ago on the _Manu_. Won't tell his name, but has mentioned Cape Town several times." "Right!" cried Preston. "Watch him carefully until I get there. I'll make the first train out." That afternoon Preston, accompanied by two chiefs of police, made his way into a little room off the public ward in the hospital in Sacramento. In bed, his face drawn and haggard until the skin seemed like parchment stretched tightly over his cheekbones, lay a man at the point of death--a man who was only kept alive, according to the physicians, by some almost superhuman effort of the will.