"A convict," I said, "who gave information to a fellow convict about to be released."
"I don't think so," said Quarles. "As a convict, these men, who have been convicts themselves, or will be, would have had sympathy with him. They hadn't any. They were afraid of him. They felt it was strange that Glider should have confided in him, and could only find an explanation by supposing that Glider had sized him up and taken his chance for the sake of the missus. We may assume, therefore, that Glider had trusted a man no one would expect him to trust. This suggests urgency, and I fancy a man, nicknamed Glider, has recently died in one of His Majesty's prisons—Portland I should guess. Probably our adventurers sailed from Weymouth. Now, Glider could not have been in Portland long. A year last February he was free to do the job with which this expedition is connected, and of which I should imagine he is not suspected by the police. Probably he was taken for some other crime soon after he had committed this one. He had no opportunity to dig up the treasure he had buried, which he certainly would have done as soon as possible. Yet Glider must have been long enough in prison to size up the dead man yonder—a work of some time, I fancy. You noticed his hands. Did they show any evidence of his having worked as a convict? You saw the mark across the forehead. That was made by a stiff cap worn constantly until a day or two ago. I think we shall find there is a warder missing from Portland."
"A warder!"
The idea was startling, yet I could pick no hole in the professor's argument.
"Even a warder is not free from temptation, and I take it this man was tempted, and fell. Glider, no doubt, told him of the captain and his mate. He had worked with them before, probably, and trusted them; also, he might think they would be a check upon the warder. I shouldn't be surprised if the warder were the only one of the three who insisted that the widow should have her share, and so came by his death. The flaw in the riddle keeps the treasure safe. Perhaps I shall solve it during the day. By the way, Wigan, it must be getting near low-water."
It was a beastly morning, persistent rain from a leaden sky. The tide was out, only a thin strip of water separating the yacht from the mud.
"I fear there will be no golfers on the links to-day to whom we might signal," said Quarles; "and I could not even swim that."
"I can," I answered.
"It would be better than spending another night here," said the professor. "Send a boat round for me, and inform the police. I am afraid the captain and his mate have got too long a start; but don't leave Lingham until we have had another talk. While I am alone I may read the riddle."
The ducking I did not mind, and the swim was no more than a few vigorous strokes, but I had forgotten the mud. As I struggled through it, squelching, knee-deep, Quarles called to me: