At the end of a week he found the vault slowly settling back into
place. When its return to the normal was complete he dared begin
boring a hole to reach the hollow tube in the concrete pile.

As he suspected, he found water in the pile--water whose sulfurous
and mineral nature confirmed his belief that a geyser reaching deep
into the bosom of the earth, as well as far back in the realms of
time, was at the bottom of the extraordinary jaunt of the tower.

Geysers were still far from satisfactory things to explain. There
are many of their vagaries which we cannot understand at all.
We do know a few things which affect them, and one thing is that
"soaping" them will stimulate their flow in an extraordinary manner.

Arthur proposed to "soap" this mysterious geyser when the renewal
of its flow should lift the runaway sky-scraper back to the epoch
from which the failure of the flow had caused it to fall.

He made his preparations with great care. He confidently expected
his plan to work, and to see the sky-scraper once more towering
over mid-town New York as was its wont, but he did not allow the
fishermen and hunters to relax their efforts on that account. They
labored as before, while deep down in the sub-basement of the
colossal building Arthur and his volunteers toiled mightily.

They had to bore through the concrete pile until they reached the
hollow within it. Then, when the evidence gained from the water
in the pipe had confirmed his surmises, they had to prepare their
"charge" of soapy liquids by which the geyser was to be stirred to
renewed activity.