consequently had much less oxygen. And the struggle for existence," he
went on, watching to see if the geologist approved each point as he made
it, "the struggle for life is, in the last analysis, a struggle for
oxygen.

"So I would say that life was a pretty strenuous proposition here, while
it lasted. Perhaps they were--" He stopped, then added: "What I can't
understand is, how did it happen that their affairs came to such an
abrupt end? And why don't we see any--er--indications?"

"Skeletons?" The architect shuddered. Next second, though, his face lit
up with a thought. "I remember reading that electricity will decompose
bone, in time." And then he shuddered again as his foot stirred that
lifeless, impalpable dust. Was it possible?

As they passed into the great house the first thing they noted was the
floor, undivided, dust-covered, and bare, except for what had perhaps
been rugs. The shape was the inevitable equilateral triangle; and here,
with a certain magnificent disregard for precedent, the builders had
done away with a ceiling entirely, and instead had sloped the three
walls up till they met in a single point, a hundred feet overhead. The
effect was massively simple.

In one corner a section of the floor was elevated perhaps three feet
above the rest, and directly back of this was a broad doorway, set in a
short wall. The three advanced at once toward it.

Here the electric torch came in very handy. It disclosed a poorly
lighted stairway, very broad, unrailed, and preposterously steep. The
steps were each over three feet high.