orribly, in there,
cursing like a madman, and uttering the most dreadful threats of what he
will do when he breaks through."

"Ah! do not let that trouble you," replied von Schalckenberg. "He
cannot break through; he is safely caged, and within the next three
hours, please God, we shall all be with you again. Now, please listen,
for there is something more that I wish you to do; but this time it is
quite easy. You know your way down to the engine-room. Please go down
there, taking your telephone with you. When you are there I will tell
you what to do."

There was a pause of about a minute, and then Lady Olivia again spoke.

"Yes, Professor," she said, "here I am. What am I to do?"

"How are you standing?" asked von Schalckenberg.

"Just inside the engine-room, with my back to the door," came the
answer.

"Good!" remarked the professor. "Then the machinery is all in front of
you. There is a large pipe--as thick as--well, nine inches in diameter
at your feet, running across the room from left to right; you cannot
mistake it."

"Yes," said Lady Olivia. "There is but one of that size near at hand.
This one is, as you say, close to my feet."

"Now look along that pipe toward your left," directed the professor.
"Do you see a small horizontal wheel standing on it, with the spindle
running down into the pipe?"

"Yes," answered her ladyship.

"Then please go to that wheel," said the German. "Grasp it on its right
and left with your two hands; pull with your right hand, and push with
your left until you cannot turn the wheel any further. Then tell me
what happens."

A pause of about half a minute ensued, and then Lady Elphinstone spoke
again.

"I have done as you directed me," she said, "and the engines have
stopped!"

"Aha!" remarked the professor, with a chuckle of satisfaction. "Yes,
that is all right. Now we shall soon overtake you. You need do no more
just now, my lady. You can go to your cabin, or where you please. But
keep the telephone about you, please, lest we should wish to speak to
you again. Courage, madame; you are now quite safe."

"Well, Professor, what is the result of your long yarn with Lady
Olivia?" demanded Sir Reginald, as he received back his instrument.

"Simply that our friend Barker is shut up in the pilot-house, from which
he cannot now escape, and Lady Olivia has just cut off the flow of
vapour at the generator; in consequence of which the engines have
stopped, for