"No." The proof was conclusive—there could be no question about it: some person or persons had been in that very room while the ambulanciers were up in the tower. Now there was, indeed, something quite startling in this thought. Who could the other, or others, have been? What was their object in entering? And did they still linger in the château? For a perceptible interval of time the boys stood in silence. The weirdness and loneliness of the situation, with only a narrow band of light between them and the deepest gloom, intensified a curious tingling sensation which the discovery had produced in the nerves of each. "What can it mean?" exclaimed Dunstan. Don's light was swiftly flashing and criss-crossing in every direction, and not a single portion of the great apartment had escaped its glare when he declared: "Fellows, there's certainly no one besides ourselves in this room." "Can there be no hiding places?" "It seems not." "If there is any one within the sound of my voice let him step forward!" exclaimed Chase. His voice, raised so as to penetrate far beyond, rang out with startling distinctness. A moment of great expectancy followed. No answer was received. "Come on, fellows! Let's get busy," burst out Don, impatiently. This proposition did not at all appeal to Chase Manning, but he made no protest, his fear of ridicule being greater than his fear of the unseen and the unknown. So, instead of leaving the Château de Morancourt at once, as they had intended, the three ambulanciers began a tramp from one great hall to another, searching—searching. And though the "man-hunt," as Don Hale dubbed it, proved both interesting and exciting it brought forth no result. After the lapse of three-quarters of an hour