down into a brute of a night, and asked him to come in and take a
glass of grog. He was only too glad to do so. He turned out to be
quite an intelligent sort of fellow, and we chatted together for ten
minutes or so.

"I had forgotten all about him when, I believe on the following night,
he reappeared in the character of a patient. He had a badly damaged
skull, and I gathered that he had had an accident with his cab and had
been pitched out into the road.

"When I had fixed him up, he asked me to do him a small favour. From
inside his tunic he pulled out a long stiff envelope, bearing no
address but the number 30 in big red letters. It was secured at both
ends with black wax bearing the imprint of a curious and complicated
seal.

"'A gentleman left this behind in the cab today, sir,' said the
man--'perhaps the one who was with me when I had the spill, and I've
got no means of tracing him; but he may be able to trace _me_ if he
happened to notice my number, or he may advertise. It evidently
contains something valuable.'

"'Then why not take it to Scotland Yard?' I asked. 'Isn't that the
proper course?'

"'It is,' he admitted; 'but here's the point: if the owner reclaims it
from Scotland Yard he's less likely to dub up handsome than if he gets
it direct from me!'

"I laughed at that, for the soundness of the argument was beyond