For a moment he lay perfectly still, listening intently, and peering the while into the darkness which encompassed him. All was perfectly still, however, save for the faint rustle in the night breeze of the mosquito curtains which surrounded his bed, and the musical tinkling of the waters of the fountain outside; while the darkness was so intense that it was only with the utmost difficulty he could dimly discern the opening of the window, which, it will be remembered, looked out upon a patio, or kind of courtyard. Suddenly the room was faintly illumined for a moment by a flicker of summer lightning, and Jack felt almost positive that during that fraction of a second he caught a glimpse of something by the open window which had certainly not been there when he retired for the night--something which suggested a crouching human figure. Stretching out his hand, Jack cautiously and noiselessly parted the mosquito curtains, with the object of getting a clear view when the next flash should come, as come he knew it would. And come it did, a minute or two later, disclosing to the young man's astonished gaze a form on hands and knees, about halfway between the window and the bed. As before, the glimmer of the lightning was but momentary, but, brief as it was, it sufficed Jack to see that the individual, whoever he might be, held a long, murderous-looking knife in his right hand; and the inference was obvious that he was there for no good purpose. Jack had learned, among other things, to act promptly and with decision, and no sooner was he again in darkness than, with a single bound, he was on his feet on the floor, where he instantly came into violent collision with the stranger, who was at that precise moment in the very act of rising from his knees. Brief as had been the flicker of the lightning, it had enabled Jack to measure his distance and to note the exact spot occupied by the unknown: the moment, therefore, that he came into contact with the intruder his left hand fell unerringly upon the right wrist of the other, which he seized in so vice-like a grip that the arm became immovable; while with his right he grasped the man by the throat and thrust him violently backward, at the same instant twining his right leg round the legs of his antagonist, with the result that both crashed to the ground, Jack being uppermost. His antagonist was an immensely powerful man, lithe and sinewy as a leopard, and he struggled furiously to free himself, hitting out savagely with his free left hand and landing one or two very nasty blows on Jack's face; until the latter, with one knee on his prostrate foe's chest, managed to get the other upon his left forearm and thus pin it to the ground. Meanwhile Jack's grip upon the throat of the man was by no means to be shaken off, and the struggles of the stranger were rapidly growing weaker as the breath was remorselessly choked out of him, when Milsom and Carlos, both of