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 du genie_.
On many occasions during the retreat in 1812-13, from the Beresina to the left of the Rhine, across the Niemen, the Vistula, the Oder, the Elbe, and the numerous other rivers which divide that immense country, the French derived vast advantages from the experience and skill of their engineers and pontoniers, several times whole corps escaping through their means from the grasp of their pursuers.