ted from Berlin, and I felt that the solution of the riddle, if
riddle it were, must be found here.

I had reached Unter den Linden. I entered a cafe and ordered a glass of
beer. The place was a blaze of light and dense with a blue cloud of
tobacco smoke. A noisy band was crashing out popular tunes and there was
a loud buzz of conversation rising from every table. It was all very
cheerful and the noise and the bustle did me good after the strain of
the night.

I drew from my pocket the slip of paper I had had from Dicky and fell to
scanning it again. I had not been twelve hours in Germany, but already I
was conscious that, for anyone acting a part, let anything go wrong with
his identity papers and he could never leave the country. If he were
lucky, he might lie doggo; but there was no other course.

Supposing, then, that this had happened to Francis (as, indeed, Red Tabs
had hinted to me was the case) what course would he adopt? He would try
and smuggle out a message announcing his plight. Yes, I think that is
what I myself would do in similar circumstances.

Well, I would accept this as a message from Francis. Now to study it
once more.

_O Eichenholz! O Eichenholz!
Wie leer sind deine Blaetter.
Wie Achiles in dem Zelte.
Wo zweie sich zanken
Erfreut sich der Dritte._

The message fell into three parts, each consisting of a phrase. The
first phrase might certainly be a warning that Francis had failed in
his mission.

_"O Okewood! how empty are thy leaves!"_

What, then, of the other two phrases?

They were short and simple. Whatever message they conveyed, it could not
be a lengthy one. Nor was it likely that they contained a report of
Francis' mission to Germany, whatever it had been. Indeed, it was not
conceivable that my brother would send any such report to a Dutchman
like van Urutius, a friendly enough fellow, yet a mere acquaintance and
an alien at that.

The message carried in those two phrases must be, I felt sure, a
personal one, relating to my brother's welfare. What would he desire to
say? That he was arrested, that he was going to be shot? Possibly, but
more probably his idea in sending out word was to explain his silence
and also to obtain assistance.

My eye recurred continually to the final phrase: "When _two_ people fall
out, the _third_ party rejoices."

Might not these numerals refer to the number of a street? Might not in
these two phrases be hidden an address at which one might find