Now, Iris, too, had been thinking deeply.  Robert Jenks bulked large in her day-dreams.  Her nerves were not yet quite normal.  There was a catch in her throat as she answered—­

“I don’t want to die.  Of course I will keep away.  What a horrid island this is!  Yet it might be a paradise.”

She bit her lip to suppress her tears, but, being the Eve in this garden, she continued—­

“How did you find out?  Is there anything—­nasty—­in there?”

“Yes, the remains of animals, and other things.  I would not have told you were it not imperative.”

“Are you keeping other secrets from me?”

“Oh, quite a number.”

He managed to conjure up a smile, and the ruse was effective.  She applied the words to his past history.

“I hope they will not be revealed so dramatically,” she said.

“You never can tell,” he answered.  They were in prophetic vein that morning.  They returned in silence to the cave.

“I wish to go inside, with a lamp.  May I?” he asked.

“Certainly.  Why not?”

He had an odd trick of blushing, this bronzed man with a gnarled soul.  He could not frame a satisfactory reply, but busied himself in refilling the lamp.

“May I come too?” she demanded.

He flung aside the temptation to answer her in kind, merely assenting, with an explanation of his design.  When the lamp was in order he held it close to the wall and conducted a systematic survey.  The geological fault which favored the construction of the tunnel seemed to diverge to the left at the further end.  The “face” of the rock exhibited the marks of persistent labor.  The stone had been hewn away by main force when the dislocation of strata ceased to be helpful.

His knowledge was limited on the subject, yet Jenks believed that the material here was a hard limestone rather than the external basalt.  Searching each inch with the feeble light, he paused once, with an exclamation.

“What is it?” cried Iris.

“I cannot be certain,” he said, doubtfully.  “Would you mind holding the lamp whilst I use a crowbar?”

In the stone was visible a thin vein, bluish white in color.  He managed to break off a fair-sized lump containing a well-defined specimen of the foreign metal.

They hurried into the open air and examined the fragment with curious eyes.  The sailor picked it with his knife, and the substance in the vein came off in laminated layers, small, brittle scales.

“Is it silver?” Iris was almost excited.

“I do not think so.  I am no expert, but I have a vague idea—­I have seen——­”

He wrinkled his brows and pressed away the furrows with his hand, that physical habit of his when perplexed.

“I have it,” he cried.  “It is antimony.”

Miss Deane pursed her lips in disdain.  Antimony!  What was antimony?

“So much fuss for nothing,” she said.