e the closing
of the spillway in August, when the flow of the river was at its
minimum. But fate, the persistent ill-fortune which had dogged the
Arcadian enterprise from the beginning, seemed to be gathering its
forces for a final blow.

"Cloud-bursts?" he questioned. "Are they frequent in the head basin of
the Boiling Water?"

"Not frequent, but very terrible when they do occur. I have seen the
Elbow toss its spray to the top of this cliff--once, when I was quite
small; and on that day the lower part of our valley was, for a few
hours, a vast flood lake."

"Was that before or after the opening of your father's mine over
yonder?" queried Ballard.

"It was after. I suppose the mine was flooded, and I remember there was
no work done in it for a long time. When it was reopened, a few years
ago, father had that immense bulkhead and heavy, water-tight door put in
to guard against another possible flood."

Ballard made the sign of comprehension. Here was one of the mysteries
very naturally accounted for. The bulkhead and iron-bound door of the
zirconium mine were, indeed, fortifications; but the enemy to be
repulsed was nature--not man.

"And the electric signal service system in the upper canyon is a part of
the defence for the mine?" he predicated.

"Yes. It has served on two or three occasions to give timely warning so
that the miners could come up and seal the door in the bulkhead. But it
has been a long time since a cloud-burst flood has risen high enough in
the Elbow to threaten the mine."

Silence supervened; the silence of the flooding moonlight, the stark
hills and the gently lapping waters. Ballard's brain was busy with the
newly developed responsibilities. There was a little space for action,
but what could be done? In all probability the newly completed dam was
about to be subjected to the supreme test, violently and suddenly
applied. The alternative was to open the spillway gate, using the
cut-off tunnel as a sort of safety-valve when the coming flood water
should reach the Elbow.

But there were an objection and an obstacle. Now that he knew the
condition of the honeycombed tunnel, Ballard hesitated to make it the
raceway for the tremendously augmented torrent. And for the obstacle
there was a mechanical difficulty: with the weight of the deepening lake
upon it, the stop-gate could be raised only by the power-screws; and the
fires were out in the engine that must furnish the power.

The Kentuckian