grand detachments and corps of observation may frequently be used with
advantage, but double or multiple lines of operation are far less
favorable than one simple line. It may however sometimes occur that the
position of the enemy's forces will be such as to make this operation
the preferable one. In that case, interior lines should always be
adopted, unless we have a vast superiority in number. Double exterior
lines, with corps several days' march asunder, must be fatal, if the
enemy, whether acting on single or double interior lines, take advantage
of his position to concentrate his masses successively against our
isolated forces. The Roman armies under the consuls Flaminius and
Servilius opposed Hannibal on exterior lines, the one by Florence and
Arrezzio, and the other by Modena and Ariminum. Hannibal turned the
position of Flaminius and attacked the Roman armies separately, gaining
a complete and decisive victory. Such also was the character of the
operations of the French in 1795, under Pichegru and Jourdan; they met
with a bloody and decisive defeat. Again in 1796, the French armies
under Jourdan and Moreau, pursued exterior lines; the Archduke Charles,
from his interior position, succeeded in defeating both the opposing
generals, and forcing them to retreat. If the two armies united had
pursued a single line, the republican flag had been carried in triumph
to Vienna.

_Converging_ lines of operation are preferable, under most
circumstances, to diverging lines. Care should be taken, however, that
the point of meeting be such that it may not be taken as a strategic
position by the enemy, and our own forces be destroyed in detail, before
they can effect a junction. In 1797 the main body of the Austrians,
under Alvinzi, advanced against Napoleon, on three separate lines,
intending to concentrate at Rivoli, and then attack the French in mass;
but Napoleon took his strategic position at Rivoli, and overthrew the