angle A, formed by the lines
of the Rhine, the Ems, and the sea, while the army E could
communicate with its bases on the Main and Rhine.

"The movement of Napoleon in 1806 on the Saale was similar. He
occupied at Jena and Naumburg the line F G H, then marched by Halle
and Dessau to force the Prussian army I upon the sea, represented
by the side A B. The result is well known.

"The art, then, of selecting lines of operations is to give them
such directions as to seize the communications of the enemy without
losing one's own. The line F G H, by its extended position, and the
bend on the flank of the enemy, always protects the communications
with the base C D; and this is exactly the maneuvers of Marengo,
Ulm, and Jena.

"When the theater of war does not border upon the sea, it is always
bounded by a powerful neutral state, which guards its frontiers and
closes one side of the square. This may not be an obstacle
insurmountable like the sea; but generally it may be considered as
an obstacle upon which it would be dangerous to retreat after a
defeat: hence it would be an advantage to force the enemy upon it.
The soil of a power which can bring into the field one hundred and
fifty or two hundred thousand troops cannot be violated with
impunity; and if a defeated army made the attempt, it would be none
the less cut off from its base. If the boundary of the theater of
war should be the territory of a weak state, it would be absorbed
in this theater, and the square would be enlarged till it reached
the frontiers of a powerful state, or the sea. The outline of the
frontiers may modify the shape of the quadrilateral so as to make
it approach the figure of a parallelogram or trapezoid, as in
Figure 2. In either case, the advantage of the army which has
control of two faces of the figure, and possesses the power of
establishing upon them a double base, will be still more decided,
since it will be able more easily to cut the enemy off from the
shortened side,--as was the case with the Prussian army in 1806,
with the side B D J of the parallelogram formed by the lines of the
Rhine, the Oder, the North Sea, and the mountainous frontier of
Franconia."

[Illustration: Fig. 2.]

The selection of Bohemia as a base in 1813 goes to prove the truth of my
opinion;