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.

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 last of the safeguards was hardly fastened firmly when Estelle listened intently.

“I hear a rumbling!” she said quietly.

Arthur reached forward and put his hand on the mass of concrete.

“It is quivering!” he reported as quietly.  “I think we’ll be on our way in a very little while.”

The group broke for the stairs, to watch the panorama as the runaway sky-scraper made its way back through the thousands of years to the times that had built it for a monument to modern commerce.