ical rules.

In popular language, however, it is usual to speak of _the military art_
when we refer to the general subject of war, and of _the military
sciences_ when we wish to call attention more particularly to the
scientific principles upon which the art is founded. We shall here
consider the military art in this general sense, as including the entire
subject of war.

As thus defined, the military art may be divided into four distinct
branches, viz.: 1st. _Strategy_; 2d. Fortification, or _Engineering_;
3d. _Logistics_; 4th. _Tactics_. Several general treatises on this art
add another branch, called _The Policy of War_, or the relations of war
with the affairs of state.

_Strategy_ is defined to be the art of directing masses on decisive
points, or the hostile movements of armies beyond the range of each
other's cannon. _Engineering_ embraces all dispositions made to enable
troops to resist a superior force the longest time possible; and also
the means resorted to by the opposing army to overcome these material
obstacles. _Logistics_ embraces the practical details of moving and
supplying armies. _Tactics_ is the art of bringing troops into action,
or of moving them in the presence of an enemy, that is, within his view,
and within the reach of his artillery. All these are most intimately
connected. A fault in tactics may occasion the loss of strategic lines;
the best combined manoeuvres on the field of battle may lead to no
decisive results, when the position, or the direction of the operation
is not strategic; sometimes not only battles, but entire campaigns, are
lost through neglect of the engineer's art, or faults in his
dispositions; again, armies would be of little use without the requisite
means of locomotion and of subsistence.

1. _Strategy_ regards the theatre of war, rather than the field of
battle. It selects the important points in this theatre, and the lines
of communication by which they may be reached; it forms the plan and
arranges the general operations of a campaign; but it leaves it to the
engineers to overcome material obstacles and to erect new ones; it
leaves to logistics the means of supporting armies and of moving them on
the chosen lines; and to tactics, the particular dispositions for
battle, when the armies have reached the destined points. It is well to
keep in mind these distinctions, which may be rendered still more
obvious by a few illustrations. The point where several lines of
co