ng, when she heard that her husband had been engaged
by the _Furious_."

He waited a moment.

"You see, Walter," he resumed, "what I am doing is to send out signals
by which the _Uncas_ can locate and follow us. She is fast, but, thank
heaven, this yacht has to go slow tonight. Sound travels in water at a
velocity of about four thousand feet a second. For instance, I find that
I get an echo in about one-twentieth of a second. That is the reflected
sound wave from the bottom, and indicates that we are in water of about
one hundred feet depth. Then I get another echo in something over two
seconds. That is the waves reflected from the _Uncas_, which has been
hovering about, waiting for something to happen. They can't be much more
than a mile and a half away, now. I had expected to signal them from the
shore, a dock or something of the sort, using this oscillator to get
around that fellow's wireless. But we're much better off on the boat."

I looked at him in amazement. "Surrounded by all this junk that may blow
us to kingdom come any second?" I demanded.

"Burke says steam is still up on all the ships tied up in the harbor so
that they can make a dash for it. They are evidently waiting for that S
O S signal."

"That's all right," I said in desperation, "But suppose they blow us up,
first?"

"Blow us up first?" he repeated. "Why, don't you understand? It is not
the _Furious_ that they are after. The whole war fleet that is hanging
around in this part of the Atlantic is to be blown up in mid-ocean, as
part of the plan to aid the escape of the interned ships in New York."

"Oh," I breathed, with a sigh of relief, "that's it, is it?"

"Yes. We'll get in bad all around if we can't stop it--Burke with the
Secret Service and ourselves with Gaskell, who doesn't dream that his
yacht is being used for the exact opposite of the purpose for which he
thinks he has lent it--to say nothing of the mess that our government
will have to face for letting these precious schemers play ducks and
drakes with our neutrality."

We waited eagerly, Kennedy sending out and receiving the submarine
signals, and I peering out anxiously into the almost impenetrable fog.

Suddenly, apparently from nowhere in the shifting mist, lights seemed to
loom up. Instead of stopping, however, the _Furious_ put on a sudden
burst of reckless speed.

The _Uncas_ was no match for her at that game. Would she escape finally,
after all?

A sharp report rang