I nodded.

We continued.  The island was like this as far as we went.  When we climbed a ridge, we found ourselves looking down on a spider-web of other valleys and canons of the same nature, all diverging to broad downs and a jump into the sea, all converging to the outworks that guarded the volcano with its canopy of vapour.

On our way home we cut across the higher country and the heads of the canons until we found ourselves looking down on the valley and Dr. Schermerhorn’s camp.  The steam from the volcanic blowholes swayed below us.  Through its rifts we saw the tops of the buildings.  Presently we made out Percy Darrow, dressed in overalls, his sleeves rolled back, and carrying a retort.  He walked, very preoccupied, to one of the miniature craters, where he knelt and went through some operation indistinguishable at the distance.  I looked around to see my companions staring at him fascinated, their necks craned out, their bodies drawn back into hiding.  In a moment he had finished, and carried the retort carefully into the laboratory.  The men sighed and stood erect, once more themselves.  As we turned away Perdosa voiced what must have been in the minds of all.

“A man could climb down there,” said he.

“Why should he want to?” I demanded sharply.

“Quien sabe?” shrugged he.

We turned in silence toward the beach.  Each brooded his thoughts.  The sight of that man dressed in overalls, carrying on some mysterious business, brought home to each of us the fact that our expedition had an object, as yet unknown to us.  The thought had of late dropped into the background.  For my part I had been so immersed in the adventure and the labour and the insistent need of the hour that I had forgotten why I had come.  Dr. Schermerhorn’s purpose was as inscrutable to me as at first.  What had I accomplished?

The men, too, seemed struck with some such idea.  There were no yarns about the camp fire that night.  Percy Darrow did not appear, for which I was sincerely sorry.  His presence might have created a diversion.  For some unknown reason all my old apprehensions, my sense of impending disaster, had returned to me strengthened.  In the firelight the Nigger’s sullen face looked sinister, Pulz’s nervous white countenance looked vicious.  Thrackles’ heavy, bulldog expression was threatening, Perdosa’s Mexican cast fit for knife work in the back.  And Handy Solomon, stretched out, leaning on his elbow, with his red headgear, his snaky hair, his hook nose, his restless eye and his glittering steel claw—­the glow wrote across his aura the names of Kid, Morgan, Blackbeard.  They sat smoking, staring into the fire with mesmerised eyes.  The silence got on my nerves I arose impatiently and walked down the pale beach, where the stars glimmered in splashes along the wettest sands.  The black silhouette of the hills against the dark blue of the night sky; the white of breakers athwart the indistinct heave of the ocean, a faint light marking the position of the Laughing Lass—­that was everything in the world.  I made out some object rolled about in the edge of the wash.  At the cost of wet feet I rescued it.  It was an empty brandy bottle.