s smooth and apparently solid. Suddenly he put out his foot
and stepped upon nothing but air. He tried to draw back, but it was
too late, and with a cry that could not be suppressed he went down into
pitch-black space. He struck on some sharp rocks, and then his senses
forsook him.

The fall was a perilous one and it was only by good luck that Adam
Adams did not have his brains dashed out. As it was he remained
unconscious for fully half an hour, and came to his senses to find a
large lump on his head and the blood flowing over his face. His left
shoulder was lame and for the time being he was afraid it was broken.

The rocks upon which he had fallen rested in several inches of water,
and with this water he washed off the blood and bathed his hurts as
best he could in the darkness.

The mishap made him reach but one conclusion. Matlock Styles had
placed him there so that he might injure if not kill himself!

"The rascal!" muttered the detective. "If I ever get out of here he
shall suffer for this if for nothing else!"

It took him some time to pull himself together and get his breath.
Then he felt around cautiously, being careful to take no more steps
until he was sure of his footing.

In a quarter of an hour he knew he was a prisoner in a circular cistern
perhaps twelve feet in diameter and of uncertain depth. The walls were
perpendicular, smooth and covered with slime, so to crawl up was
totally out of the question.

"A pretty fix to be in," he mused. "If Styles had wanted to kill and
bury me he couldn't have started out better. Ha! What's that?" He
listened and then smiled grimly to himself. "Rats. I suppose there
are scores of them around this place. I must see to it that they don't
get a chance to feed upon my body!"

What was the best way to get out? For some minutes the detective
studied the situation. In one of his pockets he had stuffed the rope
taken from his legs, thinking it might come in handy in some way. He
made a small loop at one end of this rope and threw it upward a dozen
times or more. At last it caught on something and held fast.

Being on guard, in case he might fall backward, Adam Adams pulled
himself up on the rope. It had caught on a sharp stone close to the
top of the cistern and with an effort he drew himself to the flooring
above.

"Thank Heaven for that," he murmured. "I must steer clear of such
pitfalls in the future. If only I had a light!"

But his pock