In the campaign of 1799, the Archduke attempted to pass the Aar, and attacked the French on the opposite side, but for want of suitable equipage his operation was delayed till the enemy had collected sufficient forces to intercept the passage; he was now obliged to enter into a stipulation for a suspension of hostilities, and to withdraw his bridges. The operations of the French in the campaign of 1800, led to the most glorious results, but their execution was attended with the greatest difficulties. The passage of the Alps was greatly facilitated by the ability of the chief engineer, Marescot, and the skill of the troops under his command; and the facility of passing rivers afforded Napoleon by his pontoniers, had an important influence upon the success of the campaign. "The army of the reserve had many companies of pontoniers and sappers; the pontons of course could not be taken across the St. Bernard, but the pontoniers soon found materials on the Po and Tesin for constructing bridge equipages." Moreau's army in the same year profited well by his pontoniers, in the passages of the Inn, the Salza, the Traun, the Alza, &c., and in the pursuit of the Austrian army--a pursuit that has but a single parallel example in modern history. The facility with which Napoleon crossed rivers, made forced marches, constructed redoubts, fortified depots, and grasped the great strategic points of the enemy in the campaign of 1805, resulted from the skilful organization of his army, and the efficiency given to the forces employed in these important operations. The engineer staff of the French army at this period, consisted of four hundred and forty-nine officers, and there were four battalions of sappers, of one hundred and twenty officers and seven thousand and ninety-two men; six companies of miners, of twenty-four officers and five hundred and seventy-six men; and two regiments of pontoniers, of thirty-eight officers and nine hundred and sixty men. On the contrary, the enemy's neglect of these things is one of the most striking of the many faults of the war, and his ill-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.