Before they had finished, the builder, who had been puzzling over the extraordinary suddenness with which that cloud of dust had settled, received an inspiration.  He was carrying note-book and camera.  With his pliers he tore out a sheet from the former, and holding book in one hand and the leaf in the other, he allowed them to drop at the same instant.

They reached the ground together.

“See?” The architect repeated the experiment.  “Back home, where there’s air, the paper would have floated down; it would have taken three times as long for it to fall as the book.”

Smith nodded, but he had been thinking of something else.  He said gravely:  “Remember what I told you—­it’s air that insulates the earth from the ether.  If there’s no air here—­” he glanced out into the pitiless sunlight—­“then I hope there’s no flaw in our insulation.  We’re walking in an electrical bath.”

They looked around.  Objects were pretty distinct now.  They could easily see that the floor was covered with what appeared to be machines, laid out in orderly fashion.  Here, however, as outside, everything was coated with that fine, cream-colored dust.  It filled every nook and cranny; it stirred about their feet with every step.

The geologist led the way down a broad aisle, on either side of which towered immense machinery.  Smith was for stopping to examine them one by one; but the others vetoed the engineer’s passion, and strode on toward the end of the triangle.  More than anything else, they looked for the absent population to show itself.

Suddenly Van Emmon stopped short.  “Is it possible that they’re all asleep?” He added that, even though the sun shone steadily the year around, the people must take time for rest.

But Smith stirred the dust with his foot and shook his head.  “I’ve seen no tracks.  This dust has been lying here for weeks, perhaps months.  If the folks are away, then they must be taking a community vacation.”

At the end of the aisle they reached a small, railed-in space, strongly resembling what might be seen in any office on the earth.  In the middle of it stood a low, flat-topped desk, for all the world like that of a prosperous real-estate agent, except that it was about half a foot lower.  There was no chair.  For lack of a visible gate in the railing, the explorers stepped over, being careful not to touch it.

There was nothing on top of the desk save the usual coat of dust.  Below, a very wide space had been left for the legs of whoever had used it; and flanking this space were two pedestals, containing what looked to be a multitude of exceedingly small drawers.  Smith bent and examined them; apparently they had no locks; and he unhesitatingly reached out, gripped the knob of one and pulled.

Noiselessly, instantaneously, the whole desk crumbled to powder.  Startled, Smith stumbled backwards, knocking against the railing.  Next instant it lay on the floor, its fragments scarcely distinguishable from what had already covered the surface.  Only a tiny cloud of dust arose, and in half a second this had settled.