ir Ralph recapitulated the scene at Berkeley Square,
giving even the epithets by which the girl had addressed him. Foyle
tapped lightly on his desk with the end of a penholder. The event had
been as he thought. He looked Sir Ralph straight in the eye.

"She told you that you were a spy--that I had used you as a tool," he
said sharply. "You have been hurt by her words. I don't want you to feel
that you are anything but a free agent, or to do anything that you
consider dishonourable. But I must know whether you are still willing to
act with us, or whether you wish to stand aside."

Fairfield threw the stump of cigarette viciously into the fire.

"I am acting with you, of course," he answered sullenly, "though I wish
you to ask for my help only when it is absolutely necessary. What I
complain of is, that I have not been frankly treated, and that I have
been placed in an invidious position with Lady Eileen. You must remember
that I have feelings, and that it is not pleasant to be told one is
acting as a spy, especially by--by an old friend. You know, Mr. Foyle,
that I have only been wishful to serve those I have known."

There was something pathetic in his endeavour to justify his actions to
himself. Foyle murmured a sympathetic, "I understand--yes, yes, I know,"
and then became thoughtful.

"After all," he said at last, "this does not make us so very badly off.
You are openly on our side now, Sir Ralph, so there can be no fear of
your again being accused of acting in an underhand manner. There is
nothing more to be done at the moment. I will keep you posted as to any
steps we are taking."

"Very well. Good morning, Mr. Foyle."

The baronet was gone. The superintendent resumed his perusal of
documents. He felt some little compunction at what had happened. Yet it
was his business to clear up the mystery, and to use what instruments
came to his hand, so long as the law was not violated. There is a code
of etiquette in detective work in which the first and most important
rule is: "Take advantage of every chance of bringing a criminal to
justice." In using Fairfield as an instrument, Foyle was merely
following that code.

In a little, Foyle had finished and sent for Green. The chief inspector
came with a report.

"A woman brought the advertisement to Fleet Street, sir," he said.
"Blake has just telephoned up that he and Lambert are keeping her under
observation. He 'phoned earlier that Lady Eileen Meredith had been
t