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 dépôts, 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.
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 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. When, however, the disasters of this retreat had absorbed most of the material of the army, and had sadly thinned the ranks of men of skill and experience, they sustained many severe, and, in other circumstances, unnecessary losses. Of this character we may mention the passage of the Elster by the bridge of Lindnau, where, through the ignorance and carelessness of those charged with the mines, and through the want of suitable bridge arrangements, thousands of brave men were buried in the muddy waters of this small river. So sensibly did Napoleon feel this want of bridge equipages, in the winter of 1813-14, that he addressed to his minister of war, on this subject, the following remarkable words: "If I had had pontons, I should have already annihilated the army of Schwartzenberg, and closed the war; I should have taken from him eight or ten thousand wagons, and his entire army in detail; but for want of the proper means I could not pass the Seine." Again, on the 2d of March he wrote: "If I had had a bridge equipage this morning, Blücher's army had been lost." Whoever will examine the details of the operations of this campaign, will be convinced of the full force of these remarks.
In Spain in 1808, Sir John Moore, in order to assist the native forces, had penetrated so near the army of Napoleon, that retreat became exceedingly difficult, and he was several times on the point of being lost. The English army was at this time very deficient in engineer troops, and Moore suffered much for want of miners to destroy bridges, and pontoniers to construct new ones. In order to cover his retreat and impede the advance of the French, the commander-in-chief, says Napier, "directed several bridges to be destroyed, but the engineers [for want of miners and miner's tools] failed of success in every attempt."
In Soult's retreat, in 1809, he crossed the Duero at Oporto, and destroyed the bridges so as to cut off the pursuit of Wellington. But while Soult, deceived by treachery in his own corps, neglected to guard the river with proper vigilance, Wellington collected boats at different points, crossed over his army, surprised the French, and, had it not been for the singular delay and indecision of General Murray, would most certainly have forced the entire army to capitulate; as it was, his operation produced a decided influence on the campaign, and effected the safety of Beresford's corps. Soult destroyed his artillery and baggage, and hastily retreated through the mountain passes; but his army was again arrested at the river Cavado, and placed on the very brink of destruction, when the brave and skilful Dulong succeeded in effecting a passage at the Ponte Nova; the same daring officer opened, on the same day, a way for the further escape of the French across the Misarella by the Saltador.
In the pursuit of Massena, in 1810, it was important to the English to cross the Guadiana, and attack the French before Badajos could be put in a state of defence. Beresford was directed by Wellington to pass this river at Jerumina, where the Portuguese had promised to furnish pontons; but they neglected to fulfil their engagement, and the army had to wait till Capt. Squire, an able and efficient officer of engineers, could construct other means for effecting a passage. Every thing was done that genius could devise and industry execute; nevertheless, the operations of the army were greatly delayed—"a delay," says the historian, "that may be considered as the principal cause of those long and bloody operations which afterwards detained Lord Wellington more than a year on the frontiers of Portugal."
We might prolong these remarks by discussing the passages of the Ceira and Alva, and their influence on the pursuit of Massena; Wellington's passage of the Tagus, and his retreat from Burgos in 1812; the passage of the Adour and Garonne in 1814; and the failure of the mines to blow up the bridges of Saltador, Alcantara, &c.; but a sufficient number of examples, it is believed, has already been adduced to show the advantage of maintaining a properly organized and instructed body of sappers, miners, and pontoniers, and the fatal results attending the want of such troops, as a component part of an army organization.
It has already been remarked that the infantry of an army must always form the basis of the apportionment; and by the general rule laid down by military writers, the cavalry should be from one-fourth to one-sixth of the infantry, according to the character of the war; the artillery about two-thirds of the cavalry, or one-seventh of the infantry; and the engineers from one-half to three-fourths of the artillery,—say about two-thirds. The staff and administrative corps must vary according to the nature of the organization, and the character of the theatre of war. The former ought to be from two to five in a thousand, and the latter from twenty-five to seventy-five,[[40]] as a general rule. These ratios would give for a good army organization;