So I dived into my bag and from the piles of literature it contained
picked up a book at random. It was a German brochure: _Gott strafe
England!_ by Prof. Dr. Hugo Bischoff, of the University of Göttingen.
The irony of the thing appealed to my sense of humour. "So be it!" I
said. "The worthy Professor's fulminations against my country shall have
the honour of harbouring the document which is, apparently, of such
value to _his_ country!" And I tucked the little canvas case away inside
the pages of the pamphlet, stuck the pamphlet deep down among the books
and shut the bag.

Seeing its harmless appearance the cloak-room receipt--I
calculated--would, unlike Semlin's document, attract no attention if, by
any mischance, it fell into wrong hands _en route._ I therefore did not
scruple to commit it to the post. Before taking my bag of books to the
cloak-room I wrote two letters. Both were to Ashcroft--Ashcroft of the
Foreign Office, who got me my passport and permit to come to Rotterdam.
Herbert Ashcroft and I were old friends. I addressed the envelopes to
his private house in London. The Postal Censor, I knew, keen though he
always is after letters from neutral countries, would leave old
Herbert's correspondence alone.

The first letter was brief. "Dear Herbert," I wrote, "would you mind
looking after the enclosed until you hear from me again? Filthy weather
here. Yours, D.O." This letter was destined to contain the cloak-room
receipt. To conceal the importance of an enclosure, it is always a good
dodge to send the covering letter under separate cover.

"Dear Herbert," I said in my second letter, "If you don't hear from me
within two months of this date regarding the enclosure you will have
already received, please send someone, or, preferably, go yourself and