cave, for it was constructed not of the material of the cliff, but of something which felt like very hard wood.
Silently I groped over its surface with my hands, and presently was rewarded by the feel of the button which as commonly denotes a door on Mars as does a door knob on Earth.
Gently pressing it, I had the satisfaction of feeling the door slowly give before me, and in another instant we were looking into a dimly lighted apartment, which, so far as we could see, was unoccupied.
Without more ado I swung the door wide open and, followed by the huge Thark, stepped into the chamber, As we stood for a moment in silence gazing about the room a slight noise behind caused me to turn quickly, when, to my astonishment, I saw the door close with a sharp click as though by an unseen hand.
Instantly I sprang toward it to wrench it open again, for something in the uncanny movement of the thing and the tense and almost palpable silence of the chamber seemed to portend a lurking evil lying hidden in this rock-bound chamber within the bowels of the Golden Cliffs.
My fingers clawed futilely at the unyielding portal, while my eyes sought in vain for a duplicate of the button which had given us ingress.
And then, from unseen lips, a cruel and mocking peal of laughter rang through the desolate place.
