"I didn't think it likely that he had hidden the cases, mind you. Because he would have had to dive again to get them, and would have been just as awkwardly placed in fetching them to the light of day then as ever. Besides, he couldn't come diving here again in the company's dress without some explanation. So what more likely than that he would make some ingenious arrangement with an accomplice, whereby he might make the gold in some way accessible to him?
"We went under water. I kept my eyes open, and observed, among other things, that the vessel was one of those well-kept 'swell' ones on which all the hatch gratings and so on are in plain oak or teak, kept holystoned. This (with the other things) I put by in my mind in case it should be useful. When we went over the side and looked at the great gap, I saw that it would have been quite easy to get at the broken bullion-room partition from outside."
"Yes," remarked Merrick, "it would be no trouble at all. The ladder goes down just by the side of the breach, and any one descending by that might just step off at one side on to the jagged plating at the level of the after orlop, and reach over into the bullion safe."
"Just so. Well, next I turned my attention to the sea-bed, which I was extremely pleased to see was of soft, slimy claystone. I walked about a little, getting farther and farther away from the vessel as I went, till I came across that clean stone which I turned over with my foot. Do you remember?"
"Yes."
"Well, that was noticeable. It was the only clean, bare stone to be seen. Every other was covered with a green growth, and to most clumps of weed clung. The obvious explanation of this was that the stone was a new-comer—lately brought from dry land—from the shingle on the sea-shore, probably, since it was washed so clean. Such a stone could not have come a mile out to sea by itself. Somebody had brought it in a boat and thrown it over, and whoever did it didn't take all that trouble for nothing. Then its shape told a tale; it was something of the form, rather exaggerated, of a loaf—the sort that is called a 'cottage'—the most convenient possible shape for attaching to a line and lowering. But the line had gone, so somebody must have been down there to detach it. Also it wasn't unreasonable to suppose that there might have been a hook on the end of that line. This, then, was a theory. Your man had gone down alone to take his measurement, had stepped into the broken side, as you have explained he could, reached into the bullion-room, and lifted the two cases. Probably he unfastened the cord, and brought them out one at a time for convenience in carrying. Then he carried the cases, one at a time, as I have said, over to that white stone which lay there sunk with the hook and line attached by previous arrangement with some confederate. He detached the rope from the stone—it was probably fixed by an attached piece of cord, tightened round the stone with what you call a timber-hitch, easily loosened—replaced the cord round the two cases, passed the hook under the cord, and left it to be pulled up from above. But then it could not have been pulled up there in broad daylight, under your very noses. The confederates would wait till night. That meant that the other end of the rope was attached to some floating object, so that it might be readily recovered. The whole arrangement was set one night to be carried away the next."
"But why didn't Gullen take more than two cases?"
"He couldn't afford to waste the time, in the first place. Each case removed meant another journey to and from the vessel, and you were waiting above for his measurements. Then he was probably doubtful as to weight. Too much at once wouldn't easily be drawn up, and might upset a small boat.
"Well, so much for the white stone. But there was more; close by the stone I noticed (although I think you didn't) a mark in the claystone. It was a triangular depression or pit, sharp at the bottom—just the hole that would be made by the sharp impact of the square corner of a heavy box, if shod with iron, as the bullion cases are. This was one important thing. It seemed to indicate that the boxes had not been lifted directly up from the sea-bed, but had been dragged sideways—at all events at first—so that a sharp corner had turned over and dug into the claystone! I walked a little farther and found more indications—slight scratches, small stones displaced, and so on, that convinced me of this, and also pointed out the direction in which the cases had been dragged. I followed the direction, and presently arrived at another stone, rather smaller than the clean one. The cases had evidently caught against this, and it had been displaced by their momentum, and perhaps by a possible wrench from above. The green growth covered the part which had been exposed to the water, and the rest of the stone fitted the hole beside it, from which it had been pulled. Clearly these things were done recently, or the sea would have wiped out all the traces in the soft claystone. The rest of what I did under water of course you understood."
"I suppose so: you took the bearings of the two stones in relation to the ship by pacing the distances."