He snarled, then, angrily at himself under his breath. That was the method of the "cusher," which, on a certain occasion, he had branded with so much contempt! The record of Shadow Varne was marred by no such crudeness as that. A cusher without art! It brought him a sense of intense irritation that the thought should even have entered his mind.

Why had it?

He shook his head. Was it impatience, or perhaps, rather, a prescience prompting him to be through and done with this with the least possible delay? Were the events that had happened since he had left England insidiously taking effect upon him to the detriment of his customary cold and measured judgment? Well, he would see to it that nothing of that sort should happen! Crime was a science; its procedure was calculated, methodical, orderly, denying scruples. He had always approached it as a science; he proposed never to approach it in any other way. The case in point, for instance: Once he knew exactly where this hidden half-million was, where he could lay his hands on it whenever he desired at an instant's notice—and he would locate its precise position inside the hut there as soon as the old maniac returned home to his bed—Mr. Marlin would be removed. But that must be accomplished apparently through an accident—and the accident must be such as to serve as proof, so to speak, that Captain Francis Newcombe could not possibly have had any part in it. This became the more essential now in view of that infernal voice last night. The nature of the accident itself was a mere detail. The choice was legion. There had been others who, becoming encumbrances in the path of Shadow Varne, had met with accidents. What folly to go in there now—and have the whole island aroused by the crime of murder and invaded by the police; with the crime itself proclaiming the fact that the murder had been done for the money the old madman was known to have had somewhere, but which was now obviously in the possession of some one, to wit, the murderer!

Bah! What was the matter with him? Did he need to rehearse the obvious? Mr. Marlin's secret would die with him; and, being unable to find the money, they would give the old maniac more credit for cunning and originality than was due to the moss-eaten method of selecting a hiding place under the floor of an old hut! The pitiful fool! Under the floor! That was where the treasure was always hidden—in every book he had ever read!

The crooning continued. It began to get a little on his nerves. It was interminable. Would the man stay here until daylight? No; that was hardly likely—not if he ran true to form. Old Marlin hadn't stayed out until daybreak last night when Polly and he, Captain Francis Newcombe, had watched the other go in under the verandah.

It might have been an hour, though it seemed two, when at last Captain Francis Newcombe rose silently to his feet. The crooning had finally ceased, and in its place there came now a series of low, thudding sounds, as though soft earth were being tamped into place; and then he heard the door creak a little as it was opened and closed. An instant later the footsteps of the old man died away along the path by which he had come.

Captain Francis Newcombe stepped quickly around to the other side of the hut, and tried the door. It was unlocked. He smiled in a sort of grim humour as he pushed it open, and, entering, closed it again behind him. That was the first sign of intelligence—no, applied to a maniac, it could hardly be termed intelligence!—well then, craftiness that measured up in at least a little way to the intensive order of cunning with which the insane in general were popularly credited. An unlocked door was no mean safe-guard. The last place one would expect to find, or look for, a half-million dollars would be behind an unlocked door!

His flashlight threw an inquisitive circle of light around the interior. Whatever the place had been used for at one time, it was decidedly neglected and in disuse now. The flooring was in an advanced state of decay. His eyes followed the ray of the flashlight as it held on a spot on the flooring near the door. Yes, knowing beforehand that some pieces of the flooring there had been lifted, he could see that such was the case in spite of the fact that the pieces had been very neatly replaced.

The flashlight continued its tour of inspection. There was a pile of rubbish and some old barrels over in the far corner. He stepped quickly across to these and nodded his head sharply in satisfaction, as, tucked in behind the barrels, he found what he had been looking for. Mr. Marlin had been digging. Exactly! Here was the spade. He lifted it up and examined it. Particles of fresh earth still clung to it.

Captain Francis Newcombe stood still now for an instant to listen. And as he listened his brows gathered in a savage frown of annoyance. Why this exaggerated precaution? What did he expect to hear? What sound could there be? The old fool was finished for the night. There wasn't the slightest chance that he would return. Why should he, Captain Francis Newcombe, waste time now, when with a moment's work he could satisfy himself that the half-million dollars that had brought him to Manwa Island was definitely within his reach? Was that it? Was it psychological? Was it that voice he was listening for again?