Soundings taken by the rope showed that only too clearly.

The water flowed three feet over the false bottom Robin had contrived the better to conceal his hiding place, whilst below that there was fully ten feet of water; and Petronella's face grew long as she saw the result of the sounding, for she could not imagine how any treasure could be got at that lay thirteen feet below the surface of the water.
"Never mind that, sister mine," said Cuthbert.

"Belike it is to that very fact that it owes its long safety.

Even Robin must have known that to bring it forth again must be a matter of time and patience.

He could not visit it in a moment of haste or fright, and filch a piece away as he would.