il 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.

Great quantities of the soap used by the scrubwomen in scrubbing
down the floors was boiled with water until a sirupy mess was
evolved. Means had then to be provided by which this could be quickly
introduced into the hollow pile, the hole then closed, and then
braced to withstand a pressure unparalleled in hydraulic science.
Arthur believed that from the hollow pile the soapy liquid would
find its way to the geyser proper, where it would take effect in
stimulating the lessened flow to its former proportions. When that
took place he believed that the building would return as swiftly
and as surely as it had left them to normal, modern times.

The telephone rang in his office, and Estelle answered it. Arthur
was on the wire. A signal was being hung out for all the castaway
to return to the building from their several occupations. They were
about to soap the geyser.

Did Estelle want to come down and watch? She did! She stood in the
main hallway as the excited and hopeful people trooped in. When
the last was inside the doors were firmly closed. The few friendly
Indians outside stared perplexedly at the mysterious white strangers.

The whites, laughing excitedly, began to wave to the Indians. Their
leave-taking was premature.

Estelle took her way down into the cellar. Arthur was awaiting her
arrival. Van Deventer stood near, with the grinning, grimy members
of Arthur's volunteer work gang. The massive concrete pile stood
in the center of the cellar. A big steam-boiler was coupled to a
tiny pipe that led into the heart of the mass of concrete. Arthur
was going to force the soapy liquid into the hollow pile by steam.

At a signal steam began to hiss in the boiler. Live steam from
the fire-room forced the soapy sirup out of the boiler, through
the small iron pipe, into the hollow that led to the geyser far
underground. Six thousand gallons in all were forced into the
opening in a space of three minutes.

Arthur's grimy gang began to work with desperate haste. Quickly
they withdrew the iron pipe and inserted a long steel plug,
painfully beaten from a bar of solid metal. Then, girding the
colossal concrete pile, ring after ring of metal was slipped on,
to hold the plug in place.

The l