army corps was supported by its reserve
corps, which showed itself as quick in mobilization and preparation
as the active corps.

Germany, while maintaining sufficient forces on the Russian front,
was still able to put in the field for its great offensive against
France a more numerous body of troops than would have been believed
in France. This permitted them to maintain in Alsace, in Lorraine,
and in Belgian Luxembourg armies as numerous as those which faced
them on the French side, and at the same time to mass the major
part of their troops on the right so as to pour into the valley
of the Oise their chief invading forces.

This explains why the French left, which was exposed to the offensive
of the German right, was obliged to make a rapid retreat, permitting
the German armies of General von Kluck and General von Buelow to
advance with all speed in the direction of Paris.

The French military staff, as soon as they perceived the danger
that threatened, proceeded to a new alignment of forces. As long
as this alignment of forces could not be effected the retreat had
to continue. As soon as it was accomplished, as soon as General
Joffre had his armies well in hand and the situation of his troops
well disposed, he checked the retreat, gave the signal for the
offensive, and so followed the great Battle of the Marne.

The German plan consisted, therefore, in delivering the main blow
through the medium of the right wing of the German forces, consisting
of the army of Von Kluck, the army of Von Buelow, and the army of
Von Hausen, which were to march with all speed in the direction
of Paris.

What plan had the French staff in mind to oppose to this plan of
the Germans? Its plan aimed at checking and holding the greatest
possible number of Germans by a vigorous offensive in Alsace and
Lorraine so as to prevent them from joining the three first German
armies which threatened Paris. In support of this offensive of the
armies of Alsace and Lorraine, the central French armies attacked
in the direction of the Ardennes and Belgian Luxembourg with the
object of checking the center of the German armies and then turning
toward the west so as to cooperate in the offensive of the French
forces which, aided by the British army and the Belgian army, were
fighting in Belgium.

The French armies, which are numbered from the right to the left--that
is, from the east to the west--comprised: A detachment of the Army of
Alsace that was