e a week to the whole police forces of the British Empire.

Every honest market in which the booty can be disposed of is closed. If
the thief has been unwary enough to leave a finger-print it is
photographed, and should he be an old hand the records at Scotland Yard
show his identity in less than half an hour.

All this is a matter of routine. It is "up to" the detectives still to
find their man. Should there be nothing tangible to act upon the
detectives--who know intimately the criminals in their district, and
many out of it--will try a method of elimination. "This," they will say
in effect, "is probably the work of one of half a dozen men. Let us see
who could have done it, and then we shall have something to go on. A.
and B. are in prison; C. we know to be in Newcastle, and D. was at
Southampton. Either E. or F. is the man."

The personal factor enters into the work here. A detective is expected
to be on friendly terms with professional criminals, although he must
not be too friendly. The principle can be illustrated by an anecdote of
Mr. Froest, the famous detective.

Once or twice he had arrested a notorious American crook who was
carrying on operations in this country, and whom I will call Smith. In
one of his occasional spells of liberty, Smith, who was a reputed
murderer in his own country, met Froest. "Say, chief," he drawled after
a little conversation, "I'd just hate to hurt a man like you. I always
carry a gun, and there are times when I'm a bit too handy with it. If
ever you've got to take me _never do it after six in the evening_. I'm a
bit lively then."

It is the business of a detective to know thieves. Without an
acquaintance with their habits of thought and their social customs, he
may be lost. The "informant" plays a great part in practical detective
work, and the informant, it follows, is often a thief himself. Of the
manner in which he is used, I shall have more to say later.

So it is among the friends (and enemies) of E. and F., that the
detectives set to work. It is a task that calls for tact. E., we will
suppose, is at home, and all his movements about the time of the crime
are checked and counter-checked. F. has vanished from his usual haunts.
This is a circumstance suspicious in itself, but rendered more so by
the fact that his wife is uncommonly flush of money.

Often it is harder to connect together legal evidence of guilt than to
catch a criminal. The most positive moral certainty i