eet were steaming
at a speed of 10 knots an hour, and that the train was proceeding
behind the fighting fleet without any guards of any kind around
them, our commander-in-chief might decide to keep just out of sight
until after dark, and then rush in with all his force of heavy
ships and torpedo craft, and destroy the train entirely.

But suppose the enemy fleet should advance with a "screen" consisting
of a line 10 miles long of, say, 50 destroyers, 50 miles ahead of
the main body; followed by a line of, say, 10 battle cruisers,
25 miles behind the destroyers; and with destroyers and battle
cruisers on each flank--say, 20 miles distant from the main body.
How could our scouts find out anything whatever about the size,
composition, and formation of the enemy--even of his speed and
direction of advance? The purpose of the "screen" is to prevent our
ascertaining these things; and each individual part of the screen
will do its best to carry out that purpose. All the vessels of the
screen and of the main body will be equipped with wireless-telegraph
apparatus and a secret code, by means of which instant communication
will be continuously held, the purport of which cannot be understood
by our ships. Any endeavor of any of our scouts to "penetrate the
screen" will be instantly met by the screen itself, out of sight of
the enemy's main body; and the screen cannot be penetrated in the
daytime, unless we can defeat those members of the screen that try
to hold us off. Now, inasmuch as all the considerable naval Powers
of Europe have many battle cruisers, and we have no battle cruisers
whatever, and no scouts of any kind, except three inefficient ones
(the _Birmingham_, _Chester_, and _Salem_) the degree of success
that we should have penetrating the screen in the daytime can be
estimated by any lawyer, merchant, or schoolboy.

The Laws of successful scouting and of the use of "search curves"
have been worked out mathematically, and they are used to find
an enemy of which one has certain information; but they are also
used by the enemy to avoid being found, and they aid the enemy that
is sought almost as much as they aid the seeker. And the sought
has the advantage that the use of force, if force can be employed,
breaks up the application of the mathematics of the seeker.

It is true that two main bodies of two fleets may stumble against
each other in the night-time, or in a fog or heavy mist. To prevent
this possible occurren