's office. In the
window were some blue pencils. I walked in and bought something, and
casually remarked that I shouldn't have thought there was much demand
for those pencils. 'Oh, schoolboys buy 'em,' said the old woman who
served me. 'There's old ----s' son over the way. He buys half a dozen at
a time.' Well, off I went to the grammar school that the boy was
attending, and had a talk with one of the masters. He admitted that the
lad was exceptionally clever at drawing. I was beginning to see my way,
so had the boy called out of his class into a private room. 'Now, tell
me, my boy,' I said, 'what did you do with the money you stole from your
father on such and such a date?' The bluff worked. He turned pale, and
then admitted that he had forged the initials, taken the money, and gone
on a joy-jaunt for a week while he was supposed to be staying with an
aunt. There was the luck of the idea coming in my head through looking
at those pencils."

"Have you been looking at blue pencils to-day?" asked Thornton with
interest.

"Something of the kind," admitted Foyle with a smile, and before he
could be questioned further had vanished.

He had said nothing of the blotting-paper incident, for there were times
when he wished to keep his own counsel even within the precincts of
Scotland Yard itself. He did not wish to pin himself down until he was
sure. In his own room, he unlocked the big safe that stood between the
two windows, and taking out the roll he had abstracted from Lady
Eileen's desk, surveyed it with a whimsical smile playing about the
corners of his mouth. Once he held it to the mirror, and the word
"Burghley" was plainly reflected.

"That ought to do," he murmured to himself, and, replacing it in the
safe, swung the heavy door to.

The jig-saw puzzle to which he had likened criminal investigations was
not so jumbled as it had been. One or two bits of the picture were
beginning to stick together, though there were others that did not seem
to have any points of junction. Foyle pulled out the dossier of the
case, and again went over the evidence that had been collected. He knew
it practically by heart, but one could never be too certain that nothing
had been overlooked. He was so engaged when Mr. Fred Trevelyan was
announced.

"Fred Trevelyan? Who is he?" he asked mechanically, his brain still
striving with the problem he wished to elucidate.

"That's the name he gave, sir," answered the clerk, who ranked as a