t a picture left hanging in any of the offices. Metal
paper-knives bought huge quantities of provisions from the eager
Indian traders, and the story was current in the tower that Arthur
had received eight canoe-loads of corn and vegetables in exchange
for a broken-down typewriter. No one could guess what the savages
wanted with the typewriter, but they had carted it away triumphantly.

Estelle smiled tenderly to herself as she remembered how Arthur had
been the leading spirit in all the numberless enterprises in which
the castaways had been forced to engage. He would come to her in a
spare ten minutes, and tell her how everything was going. He seemed
curiously boylike in those moments.

Sometimes he would come straight from the fire-room--he insisted on
taking part in all the more arduous duties--having hastily cleaned
himself for her inspection, snatch a hurried kiss, and then go
off, laughing, to help chop down trees for the long fishing-raft.
He had told them how to make charcoal, had taken a leading part in
establishing and maintaining friendly relations with the Indians,
and was now down in the deepest sub-basement, working with a gang
of volunteers to try to put the building back where it belonged.

Estelle had said, after the collapse of the flooring in
the board-room, that she heard a sound like the rushing of
waters. Arthur, on examining the floor where the safe-deposit vault
stood, found it had risen an inch. On these facts he had built up
his theory. The building, like all modern sky-scrapers, rested on
concrete piles extending down to bedrock. In the center of one of
those piles there was a hollow tube originally intended to serve
as an artesian well. The flow had been insufficient and the well
had been stopped up.

Arthur, of course, as an engineer, had studied the construction of
the building with great care, and happened to remember that this
partly hollow pile was the one nearest the safe-deposit vault. The
collapse of the board-room floor had suggested that some change
had happened in the building itself, and that was found when he
saw that the deposit-vault had actually risen an inch.

He at once connected the rise in the flooring above the hollow
pile with the pipe in the pile. Estelle had heard liquid sounds.
Evidently water had been forced into the hollow artesian pipe under
an unthinkable pressure when the catastrophe occurred.

From the rumbling and the suddenness of the whole catastrophe