in which case it
is clear that, no matter how perfectly they might be armed, or
how quickly and accurately they could fire, one man standing on
the flank, or behind them, could kill one soldier after the other,
until all the 1,000 were killed, and be in no danger himself.

In case of attacking a ship or a column of ships from ahead, or
of attacking a line of soldiers on the flank, the effectiveness of
the method of attack lies in the fact that a number of the weapons
that are present in the force attacked cannot be used in reply.

[Illustration: Fig. 1]

_Concentration and Isolation_.--The value of "concentration" is
often insisted on, but the author desires to call attention to
a misunderstanding on this point, to which he called attention
in an essay in 1905. To the author, it seems that concentration
is a means and not an end, and that the end is what he called
"isolation" in the essay. If a man concentrates his mind on any
subject, the advantage he gains is that he prevents other subjects
from obstructing the application of his mental powers to that subject;
he pushes to one side and isolates all other subjects. In this
particular activity it does not matter whether we call his act
"concentration" or "isolation" because the whole operation goes
on inside of his own skull, and concentration on one subject
automatically produces isolation or elimination of all others.
But when concentration is attempted on external objects, the case
is very different, for concentration may not produce isolation
at all. For instance, if 4 ships in column _A_ concentrate their
fire on the leading ship in column _B_, the other 3 ships in column
_B_ are not isolated, and can fire on the ships of column _A_,
even more effectively than if column _A_ was not concentrated on
the leading ship of _B_, because they are undisturbed by being
fired at. If, however, the 4 ships of _A_ "flank" or "T" the ships
of column _B_, as shown in Fig. 2, and concentrate on the leader of
B, they thereby isolate the other ships, and practically nullify
their ability to fire at _A_.

[Illustration: Fig. 2]

This effect is approximated by an approximate "T-ing" or "flanking,"
such as is shown in Fig. 3; because the average distance from the
ships of _A_ to the leading ship in _B_ is less than the average
distance from the ships in _B_ to any ship in _A_; and because the
direction of fire from each ship in _A_ is more nearly abeam than
is the direction of