"Are you walking?" the latter queried. "If so I'll come along."

Claud Hilliard was the son of a clergyman in the Midlands, a keen,
not to say brilliant student who had passed through both school
and college with distinction, and was already at the age of
eight-and-twenty making a name for himself on the headquarters staff
of the Customs Department. His thin, eager face, with its hooked
nose, pale blue eyes and light, rather untidy-looking hair, formed
a true index of his nimble, somewhat speculative mind. What he did,
he did with his might. He was keenly interested in whatever he took
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