The central space was clear.

In spite of the stuffiness, there was a damp chill to the gloomy place, by contrast to the vivid sunlight and the sweep of the trade-winds, outside.
Gavin stretched himself out at full length on the long box, and prepared to take a nap.

First he reached toward the next box--the one under which Davy had told him the key was hidden--and moved it an inch or so to make certain it was not full enough to cause him any especial effort in case he should not be released until next day and should have need of the key.
Then he shut his eyes, and let himself drift toward slumber.
It was perhaps two hours later when he was roused from a light doze by hearing something strike the concrete floor of his prison, not six feet from his head.

The thing had fallen with a slithering, uneven sound, such as might be made by the dropping of a short length of rope.
Brice sat up.

He noted that the room was no longer light enough to see across.