, and of procuring supplies with more facility. However, it
is necessary in this case to have previously arranged the means of
concentration of the columns in order to inflict a decisive blow.

This alternate application of extended and concentric movements is the
true test of a great general.

There is another kind of marches, designated as _flank marches_, which
deserves notice. They have always been held up as very dangerous; but
nothing satisfactory has ever been written about them. If by the term
_flank marches_ are understood tactical maneuvers made upon the field of
battle in view of the enemy, it is certain that they are very delicate
operations, though sometimes successful; but if reference is made to
ordinary strategic marches, I see nothing particularly dangerous in
them, unless the most common precautions of Logistics be neglected. In a
strategic movement, the two hostile armies ought to be separated by
about two marches, (counting the distance which separates the advanced
guards from the enemy and from their own columns.) In such a case there
could be no danger in a strategic march from one point to another.

There are, however, two cases where such a march would be altogether
inadmissible: the first is where the system of the line of operations,
of the strategic lines, and of the front of operations is so chosen as
to present the flank to the enemy during a whole operation. This was the
famous project of marching upon Leipsic, leaving Napoleon and Dresden on
the flank, which would, if carried out, have proved fatal to the allies.
It was modified by the Emperor Alexander upon the solicitations of the
author.

The second case is where the line of operations is very long, (as was
the case with Napoleon at Borodino,) and particularly if this line
affords but a single suitable route for retreat: then every flank
movement exposing this line would be a great fault.

In countries abounding in secondary communications, flank movements are
still less dangerous, since, if repulsed, safety may be found in a
change of the line of operations. The physical and moral condition of
the troops and the more or less energetic characters of the commanders
will, of course, be elements in the determination of such movements.

The often-quoted marches of Jena and Ulm were actual flank maneuvers; so
was that upon Milan after the passage of the Chiusella, and that of
Marshal Paskevitch to cross the Vistula at Ossiek; and their