lmann began hastily to advance towards Sombref; and Ziethen, with
32,000 men, prepared to hold the line of the Sambre as long as
possible. His chief of staff, General Reiche, states that one-third of
the Prussians were new troops, drafted in from the Landwehr; but all
the corps gloried in their veteran Field-Marshal, and were eager to
fight.

Such, then, was the general position. Wellington was unaware of his
danger; Bluecher was straining every nerve to get his army together;
while 32,000 Prussians were exposed to the attack of nearly four times
their number. It is clear that, had all gone well with the French
advance, the fortunes of Wellington and Bluecher must have been
desperate. But, though the concentration of 125,000 French troops near
Beaumont and Maubeuge had been effected with masterly skill (except
that Gerard's and D'Erlon's corps were late), the final moves did not
work quite smoothly. An accident to the officer who was to order
Vandamme's corps to march at 2 a.m. on the 15th caused a long delay to
that eager fighter.[478] The 4th corps, that of Gerard, was also
disturbed and delayed by an untoward event. General Bourmont, whose
old Vendean opinions seemed to have melted away completely before the
sun of Napoleon's glory, rewarded his master by deserting with several
officers to the Prussians, very early on that morning. The incident
was really of far less importance than is assigned to it in the St.
Helena Memoirs, which falsely ascribe it to the 14th: the Prussians
were already on the _qui vive_ before Bourmont's desertion; but it
clogged the advance of Gerard's corps and fostered distrust among the
rank and file. When, on the morrow, Gerard rejoined his chief at the
mill of Fleurus, the latter reminded him that he had answered for
Bourmont's fidelity with his own head; and, on the general protesting
that he had seen Bourmont fight with the utmost devotion, Napoleon
replied: "Bah! A man who has been a white will never become a blue:
and a blue will never be a white." Significant words, that show the
Emperor's belief in the ineradicable strength of instinct and early
training.[479]

Despite these two mishaps, the French on the morning of the 15th
succeeded in driving Ziethen's men from the banks of the Sambre about
Thuin, while Napoleon in person broke through their line at Charleroi.
After suffering rather severely, the defenders fell back on Gilly,
whither Napoleon and his main force followed them; wh