t the mystery remains how it came into the young fellow's
possession, and what he was about to do with it. As far as can be
ascertained, he was a most exemplary young man, and had no connection
whatever with any one in Admiralty employ," replied Ray; adding, "the
second fact is the one alleged by Reitmeyer, who was, in confidence,
shown a photograph of one of the larger plans."

"Then spies are, no doubt, at work here," I said.

"That cannot be denied," was his reply. "This neighbourhood opens up a
wide field of investigation to the inquisitive gentry from the
Fatherland. Knowledge of the secrets of the defences of the Firth of
Forth would be of the utmost advantage to Germany in the event of an
invasion. The local submarine defences and corps of submarine miners
have been done away with, yet the entrance of the estuary is commanded
by strong batteries upon the island of Inchkeith, opposite Leith; the
Forth Bridge is defended by masked batteries at Dalmeny at the one end
and at Carlingnose at the other, while upon Inchgarvie, the rock beneath
the centre of the bridge, is a powerful battery of six-inch guns. The
true strength of these defences, and the existence of others, are, of
course, kept an absolute secret, but Germany is equally anxious to learn
them, as she is to know exactly what our plans are regarding this new
naval base and its fortifications."

"But if the new base were established, might not the Forth Bridge be
blown into the water by the enemy, and our fleet bottled up by the
wreckage?" I ventured to remark.

"That's just the point, Jack," my friend said; "whether the Rosyth works
are carried out or not, the Germans would, without doubt, use their
best endeavours to blow up the bridge; first in order to cut direct
communication between north and south, and secondly, to prevent British
ships using St. Margaret's Hope as a haven of refuge."

"And even in face of the document discovered upon the auctioneer's
clerk, the Government deny the activity of spies!"

"Yes," said Ray in a hard voice. "A week ago I was up here, and examined
the safe in the offices we've passed. I was only laughed at for my
pains. I must admit, of course, that no document has ever been missing,
and that the safe has not been tampered with in any way."

"A complete mystery."

"One which, my dear Jack, we must solve," he said, as we retraced our
steps back to North Queensferry station, where we luckily caught a train
back to Edin