e boat along at a speed of about
twelve knots per hour, which is as fast, I fancy, as we shall ever want
her to go. If you want to go astern the movement of a single lever
reverses the whole process. There is a similar boat on the other side."

The boat having been returned to her hiding-place, the professor next
led his friends to the structure which occupied the centre of the deck.
It was a perfectly plain erection, with curved sides meeting in a kind
of stem and stern-post at its forward and after ends, with a curved
dome-like roof, several small circular windows all round its sides, and
no apparent means of entry.

"Why, how is this, professor? You have actually built your pilot-
house--for such I suppose it is--without a door," exclaimed the baronet
with returning good-humour as he perceived that, even in the event of
the _Flying Fish_ failing to fly, he would still have a very wonderful
ship for his money.

"As you have rightly supposed, this _is_ the pilot-house," answered the
professor, with one hand pressing lightly against the gleaming wall of
the structure. "But as to its being without a door, you are mistaken,
for there it is."

And as he spoke a door, hitherto unnoticed in the side of the building,
flew open.

"Why, you are a veritable magician, professor! How on earth did you
manage that?" exclaimed the colonel.

"Easily enough," answered the professor. "Just look here, all of you.
This is a secret door which it is necessary you should all know how to
open. Now, there are four of us, are there not? Very well; find the
fourth rivet from the bottom in the fourth row from the after end of the
building--here it is--push it to your left--_not_ press it; pressing is
no good--and open flies the door. Push the rivet to the _right_ when
the door is open, and you shut it--so," suiting the action to the word.
"Now, Sir Reginald, let me see if you can open that door."

The baronet opened and closed the door without difficulty; and then the
other two essayed the attempt with similarly successful results.

"That is all right," commented the professor. "Now step inside, please;
and close the door--so: when you want to open it from the inside you
simply turn this handle--so, and open it comes."

The quartette now found themselves inside the pilothouse, which proved
to be two stories in height. On their right hand they beheld the
companion-way leading to the interior of the ship, with a wide flight of