“You are not overlooking the fact that it is a button,” said Thorndyke. “I mean that it was attached to a garment.”
Both men looked at Thorndyke a little uncomfortably. Then Rodney replied:
“Your suggestion obviously is that the button was attached to a garment and that the garment contained a body. I am disposed to concede the garment, since I can think of no other means by which the button could have been held down; but I see no reason for assuming the body. I admit that I do not quite understand how Purcell’s oilskin coat could have got to the bottom of the sea, but still less can I imagine how Purcell’s body could have got to the bottom of the sea. What do you say, Phil?”
“I agree with you,” answered Phillip. “Something must have held the button down, and I can think of nothing but the coat, to which it was attached. But as to the body, it seems a gratuitous assumption—to say nothing of the various reasons for believing that Purcell is still alive. There is nothing wildly improbable in the supposition that the coat might have blown overboard and been sunk by something heavy in the pocket. As a matter of fact, it would have sunk by itself as soon as it got thoroughly soaked. You must admit, Thorndyke, that that is so.”
But Thorndyke shook his head. “We are not dealing with general probabilities,” said he. “We are dealing with a specific case. An empty oilskin coat, even if sunk by some object in the pocket, would have been comparatively light, and, like all moderately light bodies, would have drifted about the sea-bottom, impelled by currents and tide-streams. But that is not the condition in the present case. There is evidence that this button was moored immovably to some very heavy object.”
“What evidence is there of that?” demanded Rodney.
“There is the conclusive fact that it has been all these months lying continuously in one place.”
“Indeed!” said Rodney with hardly concealed scepticism. “That seems a bold thing to say. But if you know that it has been lying all the time in one place, perhaps you can point out the spot where it has been lying.”
“As a matter of fact, I can,” said Thorndyke. “That button, Rodney, has been lying all these months on the sea-bottom at the base of the Wolf Rock.”
The two brothers started very perceptibly. They stared at Thorndyke, then looked at one another and then Rodney challenged the statement.