er a moment's pause he went on. "You reconstructed the crime
with admirable skill, old chap, and nearly all you said was true.
Two men with two coffee cups did go into the library and did put
their cups on the bookstand and did go together to the well, and one
of them was a murderer and had put poison in the other's cup. But it
was not done while Boyle was looking at the revolving bookcase. He
did look at it, though, searching for the Budge book with the note
in it, but I fancy that Hastings had already moved it to the shelves
on the wall. It was part of that grim game that he should find it
first.

"Now, how does a man search a revolving bookcase? He does not
generally hop all round it in a squatting attitude, like a frog. He
simply gives it a touch and makes it revolve."

He was frowning at the floor as he spoke, and there was a light
under his heavy lids that was not often seen there. The mysticism
that was buried deep under all the cynicism of his experience was
awake and moving in the depths. His voice took unexpected turns and
inflections, almost as if two men were speaking.

"That was what Boyle did; he barely touched the thing, and it went
round as easily as the world goes round. Yes, very much as the
world goes round, for the hand that turned it was not his. God, who
turns the wheel of all the stars, touched that wheel and brought it
full circle, that His dreadful justice might return."

"I am beginning," said Grayne, slowly, "to have some hazy and
horrible idea of what you mean."

"It is very simple," said Fisher, "when Boyle straightened himself
from his stooping posture, something had happened which he had not
noticed, which his enemy had not noticed, which nobody had noticed.
The two coffee cups had exactly changed places."

The rocky face of Grayne seemed to have sustained a shock in
silence; not a line of it altered, but his voice when it came was
unexpectedly weakened.

"I see what you mean," he said, "and, as you say, the less said
about it the better. It was not the lover who tried to get rid of
the husband, but--the other thing. And a tale like that about a man
like that would ruin us here. Had you any guess of this at the
start?"

"The bottomless well, as I told you," answered Fisher, quietly;
"that was what stumped me from the start. Not because it had
anything to do with it, because it had nothing to do with it."

He paused a moment, as if choosing an approach, and then went on:
"Whe