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
communications either intersect or meet, and the centre of an arc which
is occupied by the enemy, are strategic points; but tactics would reject
a position equally accessible on all sides, especially with its flanks
exposed to attack. Sempronius at Trebbia and Varro at Cannae, so placed
their armies that the Carthagenians attacked them, at the same time, in
front, on the flanks, and in rear; the Roman consuls were defeated: but
the central strategic position of Napoleon at Rivoli was eminently
successful. At the battle of Austerlitz the allies had projected a
_strategic_ movement to their left, in order to cut off Napoleon's right
from Vienna; Weyrother afterwards changed his plans, and executed a
corresponding _tactical_ movement. By the former there had been some
chance of success, but the latter exposed him to inevitable destruction.
The little fort of Koenigsten, from its advantageous position, was more
useful to the French, in 1813, than the vast works of Dresden. The
little fort of Bard, with its handful of men, was near defeating the
operations of Napoleon in 1800, by holding in check his entire army;