ndividual fighting value, commanded by officers of equal fighting
ability; or it may mean 10 ships opposed to 9 like ships, manned
by officers and men of equal numbers and ability; or it may mean
two forces of equal strength, as regards number of men, ships,
and guns, but commanded by officers whose relative ability is as
1,000 to 900. It may be objected here that it is ridiculous so
to compare officers, because the ability of officers cannot be
so mathematically tabulated. This, of course, is true; but the
fact that we are unable so to compare officers is no reason for
supposing that the abilities of officers, especially officers of
high position, do not affect quantitatively the fighting value
of the forces they command; and the intention in mentioning this
factor is simply to show that the relative values of the forces, as
indicated in these tables, are supposed to include all the factors
that go to make them up.

Another convention, made in these tables, is that every fighting
force is able to inflict a damage in a given time that is proportional
to the force itself; that a force of 1,000, for instance, can do
twice as much damage in a given time as a force of 500 can; also
that a force can do an amount of damage under given conditions
that is proportional to the time in which it is at work; that it
can do twice as much damage in two hours, for instance, as in one
hour, _provided the conditions for doing damage remain the same_.
Another convention follows from these two conventions, and it is
that there is a period of time in which a given force can destroy a
force equal, say, to one-tenth of itself under certain conditions;
that there is some period of time, for instance, in which, under
given conditions, 1,000 men can disable 100 men, or 10 ships disable
1 ship, or 10 guns silence 1 gun. In the conflicts supposed to be
indicated in these tables, this period is the one used. It will
be plain that it is not necessary to know how long this period
is, and also that it depends upon the conditions of the fight.

In Table I, it is supposed that the chance of hitting and the
penetrability are the same to each contestant. In other words,
it is assumed that the _effective targets_ presented by the two
forces are alike in the sense that, if the two targets are hit
at the same instant by like projectiles, equal injuries will be
done. In other words, if each contestant at a given instant fires,
say a 12-inch shell, the inju