the water-mains of East London, in order that, in case of
invasion, some of the German colony could destroy the principal mains
and thus deprive half the metropolis of drinking-water.

In Leeds they had, we know, mapped out the whole water-supply, as Barker
had done at North Shields; and again in Sheffield, the plans of which
were in Berlin; but fortunately we had discovered them at work in
London, and had been able to prevent them from accomplishing their
object. Two of the men had returned to Germany on being detected, and
the other two were now at Devonport, where I had been living for a month
in irritating inactivity.

One afternoon, on receipt of a telegram from Ray, I immediately returned
to London, and as I entered the flat in Bruton Street, my friend said:

"The great _agent provocateur_ of the German Government, our friend
Hermann Hartmann, has left for Russia, Jack. His employers have sent him
there for some special reason. Would it not be wise for you to follow,
and ascertain the latest move?"

"If you think so, I'll go," I said readily. "You can take my place down
at Devonport. I've been there too long and may be spotted. Where has
Hartmann gone?"

"First back to Berlin. He has been ordered to go to Poland on a special
mission."

"Then I must pick him up in Berlin," I said.

And thus it was arranged. Next morning I obtained a special _visa_ to my
passport from the Russian Ambassador, whom I chanced to know personally,
and at 2.20 left Charing Cross for Calais, bound for Berlin.

I was puzzled why Hartmann, the most trusted agent of the Kaiser's
secret police, should be so suddenly transferred to Russian territory.
It was only temporarily, no doubt, but it behoved us to have knowledge
of what might be in the wind.

It was winter, and the journey to the German capital was cold and
cheerless. Yet I had not been there six hours before I had discovered
that Hartmann had left for a place called Ostrog, in Eastern Poland.

Therefore I lost no time in setting forth for that rather obscure place.

Yes, nowadays my life was a strange one, full of romance and constant
change, of excitement--and sometimes of insecurity.

For what reason had the great Hartmann been sent so far afield?

On leaving the railway, I travelled for two days in a sleigh over those
endless snow-covered roads and dark forests, until my horses, with their
jingling bells, pulled up before a small inn on the outskirts of the
dismal-loo