"

The river through that tunnel! Was he awake or dreaming? Paul could
scarcely believe the evidence of his ears. His heart thumped so loudly
against his ribs that he feared the conspirators might hear him.

"A chain had been drawn across the river, for all England was in a state
of alarm at the approach of the Dutchmen," went on Zuker.
"Fortifications had been added to Sheerness and Upnor Castle just here."

Brockman bent over the chart and followed the finger of Zuker.

"Just there. And the chain--what happened to the chain?"

"Sheerness was first taken, and then, taking advantage of a spring tide
and an easterly wind, the Dutch broke the chain."

"Broke it? But wasn't it fortified?"

"It was guarded by three ships, but the Dutch took them. They played
havoc with several other vessels, and advanced with six men-o'-war and
five fireships as far as Upnor Castle, where they burned three more.
That was good, wasn't it?"

"Splendid! Real pluck! Dull dogs and slow, as you say, but real grit.
I'm proud of my Dutch fore-fathers."

It was clear that Brockman, if not himself a Dutchman, was of Dutch
descent.

"The Dutch," continued Zuker, "then fell down the Medway--see, in this
direction." His finger again went to work over the chart. "They sailed
next to Portsmouth; they assaulted Harwich, and then sailed again up the
Thames as far as Tilbury--this point here--where they were repulsed.
What has been done once can be done again. Why not?"

Zuker, in his excitement, strode over in the direction of the curtain.
Paul drew back and waited. Had he seen the curtain move? Did he suspect
there was a listener behind? For a moment Paul scarcely breathed. Then
he heard Zuker pacing back to the table, and breathed freely again.

"You forget the difference in the times," answered Brockman. "Then there
were no ironclads."

"I'm forgetting nothing. Ironclads are useless without the brains behind
them. Battles nowadays are won not so much on the battlefield as by the
Intelligence Department--the Secret Service"--his voice went almost to a
whisper--"the service to which you and I belong."

A cold feeling of horror and repulsion stole over Paul as he listened.
He felt as he might have felt in listening to the rattle of a deadly
snake. These men were in the Secret Service of another country--spies,
collecting material for the enemy--material which might be used at any
time with deadly effect against England, dear old England! And