"Pshaw, my dear boy! it was simplicity itself. I don't wish to be theatrical. It is all patent and above-board. Two officers who are in command of a convict-guard learn an important secret as to buried treasure. A map is drawn for them by an Englishman named Jonathan Small. You remember that we saw the name upon the chart in Captain Morstan's possession. He had signed it in behalf of himself and his associates, — the sign of the four, as he somewhat dramatically called it. Aided by this chart, the officers — or one of them — gets the treasure and brings it to England, leaving, we will suppose, some condition under which he received it unfulfilled. Now, then, why did not Jonathan Small get the treasure himself? The answer is obvious. The chart is dated at a time when Morstan was brought into close association with convicts. Jonathan Small did not get the treasure because he and his associates were themselves convicts and could not get away."
"But this is mere speculation," said I
"It is more than that
"A letter to say that the men whom he had wronged had been set free