ll-directed
efforts to destroy the great wooden bridge across the Danube, and the
successful operations of the French sappers in securing it, formed one
of the principal turning points in the campaign.

The same organization enabled the French to perform their wonderfully
rapid and decisive movements in the Prussian campaign of 1806, and the
northern operations of 1807.

In 1809, Napoleon's army crossed, with the most wonderful rapidity, the
Inn, the Salza, the Traun, and other rivers emptying into the Danube,
and reached Vienna before the wonder-stricken Austrians could prepare
for its defence. It was then necessary for the French to effect a
passage of the Danube, which was much swollen by recent rains and the
melting snow of the mountains. Considering the depth and width of the
river, the positions of the enemy, and his preparations to oppose a
passage, with the disastrous consequences that would result to the
French from any failure in its execution; taking all these things into
consideration, Jomini pronounced it "one of the most hazardous and
difficult of all the operations of War." Here the fate of the army
depended, apparently, upon the skill and efficiency of the engineers and
pontoniers, and nobly did they discharge the trust reposed in them. When
the pontons failed, tressel-bridges were substituted, and even
fifty-four enormous boats were put in requisition. So skilfully were
these operations conducted, that Napoleon's immense army crossed over in
safety, directly in the face of a superior enemy, and the same day
fought the memorable battle of Esling. Forced to retire before numbers
vastly superior to his own, Napoleon concentrated his forces on the
island of Lobau, and intrenched his position. Surrounded by the broad
and deep channel of the Danube, and watched by numerous and skilful
enemies, it required the most constant activity and the greatest good
fortune to effect a passage. Here the skill and efficiency of the
engineers shone conspicuously; a number of bridges were thrown across
the river in the face of the Austrians, and against obstacles almost
insurmountable; the whole French army passed in safety, and soon put the
finishing stroke to that brilliant campaign. So high an estimate did
Napoleon attach to the construction of these bridges, that, when the
passage was completed, he offered to place Bertrand, the constructing
engineer, though of comparatively low rank, at the head of the French
_corps d