adio set here and he called San Francisco and sent some code
message. I think he was waiting here for someone to come. Had we
followed our original plans, we would have been miles from here before
you arrived.

"He had me bound and helpless, as he thought, but I worked my bonds a
little loose. I didn't let him know it, for I knew that the plane I had
let get away would guide a party here and I thought I might be able to
help out. When you came and attacked the house, I worked at my bonds
until they were loose enough to throw off. I saw Koskoff start my cold
apparatus to working and then he quit, because he ran out of helium.
When he started shooting again, I worked out of my bonds and tackled
him.

"He was a better man than I gave him credit for, or else he suspected
me, for about the time I grabbed him he whirled and struck me over the
head with his gun barrel and tore my face open. The blow stunned me, and
when I came to, I was thrown into this corner. I meant to have another
try at it, but I guess you rushed him too fast. He turned and ran for
the tunnel, but as he did so, he shot me through the body. I guess I
didn't look dead enough to suit him. You gentlemen broke open the door
and came in. That's all."

"Not by a long shot, it isn't," exclaimed Dr. Bird. "Where is that cold
light apparatus of yours?"

"In the tunnel."

"How do you get into it?"

"If you will open that cupboard on the wall, you'll find an open knife
switch on the wall. Close it."

* * * * *

Dr. Bird found the switch and closed it. As he did so the cabin rocked
on its foundations and both Carnes and Walter were thrown to the ground.
The thud of a detonation deep in the earth came to their ears.

"What was that?" cried the doctor.

"That," replied Smith with a wan smile, "was the detonation of two
hundred pounds of T.N.T. When you dig down into the underground cave
where we used the cold light apparatus, you will find it in fragments.
It was my only child, and I'll take it with me."

As he finished his head slumped forward on his chest. With an
exclamation of dismay Dr. Bird sprang forward and tried to lift the
prostrate form.

In an agony of desire the Doctor tightened his grip on the dying man's
shoulder. But Smith collapsed into a heap. Dr. Bird bent forward and
tore open his shirt and listened at his chest. Presently he straightened
up.

"He is gone," he said sadly, "and I guess the results of hi