e danger arises from a contrivance he
devised by which any person attempting to explore it and being unaware of
the means to guard against death, must be inevitably swept into eternity.
Now, in order to give you an illustration of this danger I will show you
the result of any adventurous person stepping down."

Taking from the mud a long iron bar, which he observed incidentally was
kept there for the purpose of guarding against death, he reached down the
shaft and placing the end of the bar upon the third step, threw his whole
weight upon it, saying:

"We will suppose you have descended until your feet stand upon this step.
Now, watch."

As the weight fell upon the step it gave way so slightly as to be almost
imperceptible, but suddenly from hidden cavities around the well-like
shaft there came six rings of long, sharp steel spikes, set inwards,
three above and three below, which, contracting as they came forward, met
and interlaced. In an instant I recognised what terrible fate would be
the lot of any adventurer who dared to enter that dark shaft. The action
of stepping upon that fatal projecting iron released hydraulic pressure
of irresistible power, and the unfortunate one, unable to ascend or
descend by reason of the danger being above and below, must be impaled
by a hundred cruel spikes, sharp and double-edged like spears, while the
bands whereon they were set must crush his bones to pulp.

I looked at this terrible device for producing an agonizing death and
shuddered. The precautions taken to prevent anyone entering the place
were the most elaborate and ingenious I had ever seen. Even if any person
learnt the secret of draining the lake, the shaft leading to the
mysterious subterranean place was unapproachable by reason of this
extraordinary mechanical device.

During five minutes the spikes remained interlaced, then automatically
they disengaged themselves, and slowly fell back into the cavity running
round the brickwork, wherein they remained concealed.

Thrice again did Omar repeat this action of pressing the bar upon the
step, each time with an exactly similar result, chatting to me the while.
Then, when for the third time the spikes had fallen back into their
places, he said:

"Now the secret to avoid this and lock the mechanism is to turn back this
little lever and place it in this catch, so. This cannot, however, be
done unless the step has been pressed three times."

And bending over he showed me