he said. "You've put your finger on the weak spot. No
one in Whitehall saw it, and they're seamen. I didn't see it, and--and
I'm called a scientist." He made an imperceptible inclination of his
head towards his companion as if to convey a compliment.

The other occupant of the broad cabin smiled a little grimly. "It's a
question of actual experience," he said. "Experience of this particular
form of warfare, and the means of meeting it hitherto at our disposal."

He pencilled some figures on a piece of paper and studied them with
knitted brows.

"It's a pity," he said presently. "You're on the brink of the most
stupendous discovery of our day. The submarine was a wonderful
invention, and there's no limit to the possibilities of its
development--or abuse. Until an effective counter can be devised it
remains a very terrible menace to civilisation in the hands of an
unscrupulous belligerent."

Sir William smoked in silence. His thin, aristocratic face, and his
level grey eyes, had a look of fatigue. "I was particularly glad to
avail myself of your invitation," he said. "I wanted practical
experience of the conditions in the North Sea--weather and visibility.
And, later on, in the North Atlantic. I'm going over to Ireland next
month." His tired eyes followed the blue smoke curling upwards. "Of
course, the experiments we tried down South answered all right for short
distances. That's what rather deceived us. They were harbour trials, no
more. We want something more exhaustive than that. And, as you say,
there's the pull of the tides to consider.... Confound the tide!"

His companion smiled. "That's what Canute said. Or words to that
effect. But it didn't help matters much."

"Quite," replied Sir William dryly. "Well, I should like to take a
patrol boat and one of our submarines for a day or two and test that new
theory--to-morrow if I may. And--while I think of it--I have promised a
young nephew of mine to dine with him to-night in his ship, if it in no
way inconveniences you?"

The other nodded, and, reaching out his hand, pressed the button of an
electric bell beside his desk.

* * * * *

It was the hour preceding dinner, and the majority of the members of the
Wardroom had congregated in the ante-room to discuss sherry and the day's
affairs before descending to their cabins to change. It was a cheerful
gathering, as the hour and the place betokened, and the usual