"You're bloody well right, it ain't!" agreed Runnells fervently. And then sharply, as the ray from the flashlight in Captain Francis Newcombe's hand streamed out: "That's where he lay last night, only the water's farther out now. It's blasted queer the thing never tackled the old madman in all this time."
"On the contrary," said Captain Francis Newcombe, "it would rather indicate that the brute was a transient visitor."
"Then I hope to Gawd," mumbled Runnells, "that it didn't like the quarters well enough to stick them for another night."
"I agree with you," laughed Captain Francis Newcombe coolly; "but, as it happens, it's low tide now and the water is out beyond where we are going—which may offer an alternative solution to old Marlin's escape. However, Runnells, that's not what we are looking for—we're looking for a keyhole."
He led the way forward, his flashlight playing on the big central concrete pier, some eight feet square, in front of him. He was chuckling quietly to himself. It being established that the old maniac's hiding place was here under the boathouse, a hiding place that was opened by a key, and that, except at low tide, was inaccessible, the precise location of that hiding place became obvious even to a child. The row of little piers that supported the structure at the sides and front were all individually too small to be hollow—and there was absolutely nothing else here except the big centre support.
With Runnells beside him now, he began to examine this centre pier under the ray of his flashlight. He walked once completely around it, making a quick, preliminary examination. The pier was some six or seven feet in height, and the concrete construction was reinforced with massive iron bands placed both horizontally and transversely between two and three feet apart, the small squares thus formed giving a sort of checkerboard effect to the mass. The lower portion was green with sea-slime. There was no apparent evidence of any opening.
But Captain Francis Newcombe had not expected that there would be.
"Look for a little hole, Runnells," he said. "Anything, for instance, that might appear to be no more than a fault in the concrete. And look particularly above high water mark. The opening is below because the old man could only get in at low tide; but the keyhole is more likely to be above out of the reach of the water because it must be watertight inside."
"Yes," said Runnells.
They made a second circuit of the pier, but carefully now, searching minutely over every inch of surface. It took a long time—a very long time—a quarter of an hour—a half hour—more.