lean and browned, and it took a second glance to realize the
tremendous height and breadth of his forehead. A craggy jutting chin
spoke of stubbornness and the relentless following up of a line of
action determined on. His head was topped with an unruly shock of
black hair which he tossed back with a hand that commanded instant
attention.

His hands were the most noteworthy thing about the famous Bureau
scientist. Long slender hands, they were, with slim tapering
fingers--the hands of an artist and a dreamer. The acid stains that
marred them could not hide their slim beauty, yet Carnes knew that
those hands had muscles like steel wire and that the doctor boasted a
grip that could crush the hand of a professional wrestler. He had seen
him tear a deck of playing cards in half and, after doubling, again in
half, with as little effort as the ordinary man would use in tearing a
bare dozen of the cards. As he climbed out of the car his keen black
eyes swept around in a comprehensive glance. Carnes, trained observer
that he was, knew that in that one glance every essential detail which
it had taken him an hour to place had been accurately noted and stored
away in the doctor's mind. He came forward to the detective.

"Has anything happened since you telephoned me?" was his first
question.

"Nothing, Doctor. I followed your instructions and also assembled a
crew of men with excavating tools."

"You're improving, Carnes. This is Dr. Lassen. This is a little out
of your line. Doctor, but you may see something familiar. What does
it look like to you?"

"Not like an earthquake, Bird, at all events. Offhand I would say that
a huge cavern had been washed in the earth and the ground had caved
in."

"It looks that way. If you are right, we should find running water if
we dig deep enough. Have you been down in the hole, Carnes?"

"No, Doctor."

"Then that's the first thing to do. You have ropes, of course?"

* * * * *

Carnes called to the waiting gang of negroes and a dozen of these
hurried up with ropes. Dr. Bird slung a rope around his body under his
arms and was lowered into the hole. The rope slackened as he reached
bottom. Carnes lay on his stomach and looked over the edge. Dr. Bird
was gingerly picking his way across the ground. He turned and called
up.

"Carnes, you and Lassen can come down if you care to."

In a few minutes the detective and the volcanologist joined him in the
cav