detective complacently, "if I did not explain so much. This explanation
habit is becoming a vice with me, and I fear I must abandon it."

"I hope for my sake you won't," said Smith more good-naturedly, "for if
left to myself I never could find out how you arrive at your wonderful
conclusions. Do you expect the Austrian diamond mystery to prove
difficult?"

"Difficult? Oh, dear no! To tell the truth, I have solved it already,
but in order to give the American a run for his money--and surely he
ought not to object to that, because he is a millionaire who has made his
fortune by giving other people runs for their money, being a railway
man--I am now on my way to Vienna. If I solved the problem off-hand for
him in London, he would have no more appreciation of my talent than you
had a moment ago when I explained why I knew this French girl came from
Chicago."

"You mustn't mind that, Cadbury," said Smith contritely. "I confess I
was irritated for a moment because it all seemed so simple."

"My dear fellow, every puzzle in this world is simple except one, and
that is to find any problem which is difficult."

"Then who stole the diamonds? The lieutenant?"

The detective smiled and gazed upwards for a few tantalizing moments at
the roof of the carriage.

"Here we have," he said at last, "an impecunious prince who marries an
American heiress, as so many of them do. The girl begins life in Austria