that was enclosed
with them.

"By Jove," he said, "they're pretty quick up at headquarters. You'll
have to excuse me a minute or two, Mr Lennard. Just stand on that side,
will you, please? Close up, we haven't too much room here. Good-bye for
the present."

In front of the desk and above the little steering-wheel there was a
mahogany board studded with two sets of ivory buttons, disposed in two
lines of six each. He touched one of these, and Lennard saw him
disappear through the floor of the conning-tower. Within a few moments
the portion of the floor upon which he had stood returned to its place,
and Lennard said to himself:

"If the rest of her works like that, she ought to be a lovely study in
engineering."

While Captain Erskine is communicating his instructions to his second in
command, and arranging the details of the coming fight, there will be
time to give a brief description of the craft on board of which Lennard
so unexpectedly found himself, and which an invention of his own was
destined to make even more formidable than it was.

To put it as briefly as possible, the _Ithuriel_ was a combination of
destroyer, cruiser, submarine and ram, and she had cost Erskine three
years of hard work to think out. She was three hundred feet long, fifty
feet broad, and thirty feet from her upper keel to her deck. This was of
course an abnormal depth for a vessel of her length, but then the
_Ithuriel_ was quite an abnormal warship. One-third of her depth
consisted of a sinking-chamber, protected by twelve-inch armour, and
this chamber could be filled in a few minutes with four thousand tons of
water. This is of course the same thing as saying she had two
waterlines. The normal cruising line gave her a freeboard of ten feet.
Above the sinking-tanks her vitals were protected by ten-inch armour. In
short, as regards armour, she was an entire reversal of the ordinary
type of warship, and she had the advantage of being impervious to
torpedo attack. Loaded torpedoes had been fired at her and had burst
like eggs against a wall, with no more effect than to make her heel over
a few degrees to the other side. Submarines had attacked her and got
their noses badly bruised in the process. It was, indeed, admitted by
the experts of the Admiralty that under water she was impregnable.

Her propelling power consisted of four sets of engines, all well below
the waterline. Three of these drove three propellers astern: the fourth
drove