up, showing a tendency, indeed, to ride
his hobbies to death. He had a particular penchant for puzzles of all
kinds, and many a knotty problem brought to him as a last court
of appeal received a surprisingly rapid and complete solution. His
detractors, while admitting his ingenuity and the almost uncanny
rapidity with which he seized on the essential facts of a case, said
he was lacking in staying power, but if this were so, he had not as yet
shown signs of it.

He and Merriman had first met on business, when Hilliard was sent to
the wine merchants on some matter of Customs. The acquaintanceship thus
formed had ripened into a mild friendship, though the two had not seen a
great deal of each other.

They passed up Coventry Street and across the Circus into Piccadilly.
Hilliard had a flat in a side street off Knightsbridge, while Merriman
lived farther west in Kensington. At the door of the flat Hilliard
stopped.

"Come in for a last drink, won't you?" he invited. "It's ages since
you've been here."

Merriman agreed, and soon the two friends were seated at another open
window in the small but comfortable sitting-room of the flat.

They chatted for some time, and then Hilliard turned the conversation to
the story Merriman had told in the club.

"You know," he said, knocking the ash carefully off his cigar, "I was
rather interested in that tale of yours. It's quite an intriguing little
mystery. I suppose it's not possible that you could have made a mistake
about those numbers?"

Merriman laughed.

"I'm not exactly infallible, and I have, once or twice in my life, made
mistakes. But I don't think I made one this time. You see, the only
question is the number at the bridge. The number at the mill is certain.
My attention was drawn to it, and I looked at it too often for there to
be the slightest doubt. It was No. 3 as certainly as I'm alive. But
the number at the bridge is different. There was nothing to draw my
attention to it, and I only glanced at it casually. I would say that
I was mistaken about it only for one thing. It was a black figure on a
polished brass ground, and I particularly remarked that the black lines
were very wide, leaving an unusually small brass triangle in the center.
If I noticed that, it must have been a 4."

Hilliard nodded.

"Pretty conclusive, I should say." He paused for a few moments, then
moved a little irresolutely. "Don't think me impertinent, old man," he
went on with a sidelo