d farther from the bridges.
But if, on the contrary, the passage be effected at one extremity of the
enemy's strategic front, by moving rapidly along this front the enemy
may be beaten throughout its whole extent,--in the same manner that
Frederick tactically beat the Austrian line at Leuthen throughout its
length,--the bridges will be secure in rear of the army, and remain
protected during all the forward movements. It was in this manner that
Jourdan, having passed the Rhine at Dusseldorf in 1795, on the extreme
right of the Austrians, could have advanced in perfect safety toward the
Main. He was driven away because the French, having a double and
exterior line of operations, left one hundred and twenty thousand men
inactive between Mayence and Basel, while Clairfayt repulsed Jourdan
upon the Lahn. But this cannot diminish the importance of the advantages
gained by passing a river upon one extremity of the enemy's strategic
front. A commander-in-chief should either adopt this method, or that
previously explained, of a central mass at the moment of passage, and
the use of eccentric lines afterward, according to the circumstances of
the case, the situation of the frontiers and bases of operations, as
well as the positions of the enemy. The mention of these combinations,
of which something has already been said in the article on lines of
operations, does not appear out of place here, since their connection
with the location of bridges has been the chief point under discussion.

It sometimes happens that, for cogent reasons, a double passage is
attempted upon a single front of operations, as was the case with
Jourdan and Moreau in 1796. If the advantage is gained of having in case
of need a double line of retreat, there is the inconvenience, in thus
operating on the two extremities of the enemy's front, of forcing him,
in a measure, to concentrate on his center, and he may be placed in a
condition to overwhelm separately the two armies which have crossed at
different points. Such an operation will always lead to disastrous
results when the opposing general has sufficient ability to know how to
take advantage of this violation of principles.

In such a case, the inconveniences of the double passage may be
diminished by passing over the mass of the forces at one of the points,
which then becomes the decisive one, and by concentrating the two
portions by interior lines as rapidly as possible, to prevent the enemy
from destro