Ralph," he remarked quietly. "Grell
credits you with intelligence enough to remember that number later. Have
you any knowledge of ciphers?"

"I have an elementary idea that to unravel them you work from the most
frequently recurring letter; E, isn't it?"

"That's right," said Foyle. "But there are other ciphers where that
system won't work. Mind you, I don't pose as an expert. If I had a
cipher to unravel, I should go to a man who had specialised in them,
exactly as I should go to a doctor on a medical question. Still, the
advertisement to-day isn't a cipher. It means exactly what it says."

"Thank you," said Fairfield drily. "I am now as wise as when I started."

"Sorry," murmured Foyle suavely. "You'll be wiser presently. The thing
isn't complete yet. If you'll excuse me a few minutes, I'll just run
through my letters, and then, if you don't mind taking a little walk,
we'll go and see Lady Eileen Meredith."

Some formal reply rose to Fairfield's lips--he never knew what. The last
time he had seen Eileen was fixed in his memory. Then she had
practically denounced him as a murderer. Since then she had learnt that
every shadow of suspicion had been cleared away from him. How would she
receive him if he visited her unexpectedly with Foyle? Why did Foyle
wish him to go? Perhaps, after all, there was nothing in it. He told
himself fiercely that there was no reason why the meeting should
embarrass him. Some day, sooner or later, they would have to meet. Why
not now? He was hungry for a sight of her, and yet he was as nervous as
a child at the thought of going to her.

The slamming of a drawer and the soft click of a key in the lock told
that Foyle had finished. He picked up a copy of the _Daily Wire_ and his
hat and gloves.

"Now, Sir Ralph," he said briskly, and together they descended the
narrow flight of stone steps which leads to one of Scotland Yard's back
doors. The detective was apparently in a talkative mood, and Fairfield
got no chance to ask the questions that were filling his mind. Spite of
himself he became interested in the flow of anecdotes which came from
his companion's lips. There were few corners of the world, civilised or
uncivilised, where the superintendent had not been in the course of his
career. He had the gift of dramatic and humorous story-telling. He spoke
of adventures in Buenos Ayres, in South Africa, Russia, the United
States, and a dozen other countries, of knife-thrusts and revolver
sh