concentrated for the purpose of defeating the enemy
when encountered. But although Strategy may be considered as the art
of bringing an opponent to battle, and Tactics as the art of defeating
him in action, there are excluded from these definitions many
considerations which influence a commander in the field.

The art of war does not commence with a strategical reconnaissance from
the air, or the saddle, to ascertain whether, and if so in what
locality and in what strength, hostile troops are being concentrated.
From information so obtained, the physical force of an enemy may indeed
be determined; but "in war (said Napoleon) moral force is to the
physical (that is, to numbers and {9} armament) as three to one," and
upwards of a hundred years later the same idea has again been
expressed. "To understand war you must go beyond its instruments and
materials; you must study in the book of history, conscientiously
analysed, armies, troops in movement and in action, with their needs,
their passions, their devotions, their capacities of all kinds. That
is the essence of the subject, that is the point of departure for a
reasonable study of the art of war" (Marshal Foch). And while dealing
with moral force it must be remembered that the moral force of opposing
leaders of nations or of armies is at least as important as that of the
nations or armies themselves, for a war is a struggle between human
intelligences rather than between masses of men. "There have been
soldiers' battles but never a soldiers' campaign" ("The Science of
War"). "It was not the Roman legions which conquered Gaul, it was
Caesar. It was not the French Army which reached the Weser and the
Inn, it was Turenne" (Napoleon). A commander must, therefore, take
into account the character, the moral fibre, as well as the ability and
the means at the disposal of his adversary. He must project his mind
to his adversary's council chamber, and putting himself in his place
must conjecture how a man of that character and of that ability will
act under the given circumstances.

History supplies many examples of mental activity of this kind.[2]
Napoleon predicted the impetuous onset of the Russian left wing against
his right at _Austerlitz_, Dec. 2, 1805, because he knew the
temperament of the Tsar Alexander. At Austerlitz, the most brilliant
of all his battles, Napoleon had 70,000 troops and was confronted by
80,000 Austrians and Russians drawn up on the Heights o