usually acts upon the recommendation of the
superintendents.

A constable, before he is promoted, must serve at least five years--in
practice, the average is eight years--and must then pass two
examinations. One of these is set by the Civil Service Commissioners to
test his education, the other is an examination in police duty before a
board of high officials. Should he be approved then for promotion he is
immediately transferred to another division. These examinations are
carried out at every step in promotion. In the words of a keen American
observer:

"That such a system is successful in bringing to the front the best men
available, that it is carried through without favouritism or political
considerations, that, in its fairness and justice, it has the confidence
of the uniformed force is a splendid commentary not only on the
integrity of the Commissioner and his administrative assistants but on
the stability and sound traditions of the entire department."

CHAPTER XI.

THE RIDDLE DEPARTMENT.

The perpetual solving of riddles is one of the commonplace duties of
Scotland Yard, not only in the C.I.D., but in every branch of the
business. Luck may, and sometimes does, help a detective to solve a
mystery; but luck never helps to quell a riot or maintain order on the
King's highway in times of stress.

It is for such matters as these that they keep a Riddle Department at
headquarters. They call it the Executive Department, but no matter--as
Mark Twain would say. It is there to supply the answers to the
conundrums that are always cropping up in police work.

Everyone in the Metropolitan Police who wants to know anything goes to
the Executive Department. And it does a heavy work by the sheer light of
common-sense and a meticulous organisation which is ready for anything,
for many of its riddles are simply variations of the great one:

"Here are twenty thousand men who must eat and sleep and guard seven
hundred square miles and seven millions of people; how can we
concentrate a hundred, a thousand, or ten thousand swiftly into a
particular district to meet an emergency without leaving other places
unguarded?"

An unthankful task. I can imagine that at times subdued but bitter
revilings are heaped upon the head of the department.

You cannot take men from the comparatively pleasant surroundings of the
West End and dump them into Dockland, for instance, without evoking
grumbles. Naturally, every division w