ust by
St. Mary Abbot church at two o'clock on the morning of the Herapath
murder," replied Carver. "That's a dead certainty! I risked five pounds
on it, anyway, for which I'll trouble you. I went on the lines of
rounding up all the cabbies I could find who were as a rule on night
duty round about that quarter, and bit by bit I got on to this fellow,
and, as I say, I gave him a fiver for just telling me a mere bit. And
it's here--he's already given some information to that old Mr.
Tertius--you know--and Tertius commanded him to keep absolutely quiet
until the moment came for a move. Well, that moment has not come yet,
evidently--the chap hasn't been called on since, anyhow--and when I
mentioned money he began to prick his ears. He's willing to tell--for
money--if we keep dark what he tells us. The truth is, he's out to get
what he can out of anybody. If you make it worth his while, he'll tell."

"Aye!" said Triffitt. "But the question is, what has he got to tell?
What does he know?--actually know?"

"He knows," replied Carver, "he actually knows who the man was that he
drove that morning! He didn't know who he was when he first gave
information to Tertius, but he knows now, and, as I say, he's willing to
sell his knowledge--in private."

CHAPTER XX

THE DIAMOND RING

Triffitt considered Carver's report during a moment of mutual silence.
If he had consulted his own personal inclination he would have demanded
to be led straight to the taxi-cab driver. But Triffitt knew himself to
be the expender of the Markledew money, and the knowledge made him
unduly cautious.

"It comes to this," he said at last, "this chap knows something which he's
already told to this Mr. Tertius. Mr. Tertius has in all probability
already told it to the people at New Scotland Yard. They, of course, will
use the information at their own time and in their own way. But what we
want is something new--something startling--something good!"

"I tell you the fellow's got all that," said Carver. "He knows the man
whom he drove that morning. Isn't that good enough?"

"Depend upon how I can bring it out," answered Triffitt. "Well, when can
I see this chap?"

"Tonight--seven o'clock," replied Carver. "I fixed that, in anticipation."

"And--where?" demanded Triffitt.

"I'll go with you--it's to be at a pub near Orchard Street," said
Carver. "Better bring money with you--he'll want cash."

"All right," agreed Triffitt. "But I'm not going t