f enemy personnel as to the sufficiency
of numbers effectively to man all implements, as to training, morale,
skill, stamina, and willingness to accept the supreme sacrifice, can
seldom be accurately known. Unless there is positive information to
the contrary, the wise commander will assume in this respect that the
status of the personnel available to his opponent is at least equal to
that of his own command. Full consideration will be given to all known
facts concerning own personnel, to the end that its worth in any
proposed situation may be properly evaluated.

The basic discussion of the psychological factors (page 125) is
applicable here as to the respective armed forces. Personal
characteristics of commanders, so far as known, deserve full study,
since they have an important bearing on relative fighting strength.
The military value of the various units and forces is a similar
consideration. The present attitude and past actions of enemy
commanders and of their commands, and the factor of racial, national,
and service characteristics, may furnish clues for correct evaluation
in this connection.

(iv) Material. The material characteristics of the commander's own
implements of war are generally known to him. The characteristics of
enemy material can only be estimated from such data as have become
available, but are not to be underestimated.

Material characteristics embrace armament, life, and mobility.

Armament relates to the caliber and number of guns, and to other
weapons such as torpedoes, mines, depth-charges and aircraft (with
their own weapons). It also includes chemical agents and other
instrumentalities, together with the types, potentialities as to
range, and the number or amount of each available, both for immediate
use and as replacements. Ammunition supply is a factor here. In the
evaluation of foreign armaments, sufficient data are often available
to make a reasonable estimate, but care is desirable not to
underestimate.

Life is the ability to withstand punishment; it is expressed in terms
of standards which can be clearly visualized. For a vessel, life is
the ability to absorb damage while carrying out its assigned task. In
the absence of definite factual data, evaluation of the life of
foreign vessels will sometimes prove difficult. Here, again, an
underestimate is dangerous.

Mobility is capability of movement. It is compounded of the elements
of speed, radius, and the ability to operate un