Brussels road in order to use
them next against Wellington. But Napoleon had left behind him Grouchy in
supreme command over a great body of troops, some 33,000 in all, whose
business it was to follow up the Prussians, to find out what road they had
taken; at the least to watch their movements, and at the best to cut off
any isolated bodies or to give battle to any disjointed parts which the
retreat might have separated from support. In general, Grouchy was to see
to it that the Prussians did not return.

In this task Grouchy failed. True, he was not given his final instructions
by the Emperor until nearly midday of the 17th, but a man up to his work
would have discovered the line of the Prussian retreat and have hung on to
it. Grouchy failed, partly because he was insufficiently provided with
cavalry, partly because he was a man excellent only in a sudden tactical
dilemma, incompetent in large strategical problems, partly because he
mistrusted his subordinates, and they him; but most of all because of an
original prepossession (under which, it is but fair to him to add, all the
French leaders lay) that the Prussian retreat had taken the form of a
flight towards Namur, along the eastern line of communications, while, as
a fact, it had taken the form of a disciplined retreat upon Wavre and the
north.

At ten o'clock in the evening of Saturday the 17th, twenty-four hours
after the battle of Ligny, and at the moment when the whole body of the
Prussian forces was already reunited in an orderly circle round Wavre,
Grouchy, twelve miles to the south of them, was beginning--but only
beginning--to discover the truth. He wrote at that hour to the Emperor
that "the Prussians had retired in several directions," one body towards
Namur, another with Blucher the Commander-in-chief towards Liege, _and a
third body apparently towards Wavre_. He even added that he was going to
find out whether it might not be the larger of the three bodies which had
gone towards Wavre, and he appreciated that whoever had gone towards Wavre
intended keeping in touch with the rest of the Allies under Wellington.
But all that Grouchy did after writing this letter proves how little he,
as yet, really believed that any great body of the enemy had marched on
Wavre. He anxiously sent out, not northward, but eastward and
north-eastward, to feel for what he believed to be the main body of the
retreating foe.

During the night he did become finally convinced b