The Campaign of Marengo, With Comments

by Herbert H. Sargent

The line of the Rhine divided the opposing armies. At the outset the French corps crossed the river at Strasburg, Brisach, Bâle, and Schaffhausen. Moreau then attempted to unite these corps before proceeding to attack Kray in force. It is always a dangerous operation to attempt a concentration upon some designated place within the enemy's lines; for, as a rule, the enemy can mass his forces there more rapidly than can the commander of an invading army. In fact, many a campaign has failed because the commanding general has attempted to unite his scattered forces at some point within the territory held by the enemy. By so doing, he gives the enemy a chance to assemble his forces between the separated columns of the attacking army, and to bring superior numbers against each column in succession. Thus, when Moreau crossed the Rhine at Strasburg, Brisach, Bâle, and Schaffhausen, he gave Kray the opportunity of defeating in detail the several French corps so widely separated from one another. Though the topography of the country was such that it did not allow Kray to concentrate his forces and throw them readily upon the separated French corps in succession, yet, had he foreseen the design of his adversary, undoubtedly he could have massed his forces between Schaffhausen and Bâle, along the Wutach, and have thus intervened between Lecourbe's corps and that of Moreau. By such a manœuvre, he would have stood a good chance of crushing both Moreau and St. Cyr, before they could have been re-enforced by either Ste. Suzanne or Lecourbe.

Again: Moreau's plan necessitated that his own corps and that of St. Cyr should make long flank marches on the German side of the river. In making these marches, the French corps necessarily exposed their own flanks to the attacks of the enemy. In fact, Kray might have issued in force from the Black Forest, and have attacked both Moreau and St. Cyr with great chances of success. Had he done so, doubtless these two French corps would have been destroyed; for they would have found themselves enclosed between a victorious enemy on one side and an impassable river on the other. Even when protected by a river, or other great natural obstacle, a flank march, in the vicinity of an active enemy, is often a difficult manœuvre; but when undertaken in an enemy's country, between an unfordable river on one side, and an active enemy on the other, it then becomes an extremely delicate and dangerous operation.

It will also be noticed that though St. Cyr, in his march across the hills and mountains from Friburg to St. Blazien, and thence to Stuhlingen, flanked and protected the reserve in its march from Bâle to Schaffhausen, yet he was obliged to send his artillery by the river road. Had he, therefore, been attacked in force during this movement, he would have been compelled to fight without his artillery. Thus the fighting power of his corps would have been diminished; and his efforts would have been directed towards the protection of his cannon, which, under ordinary circumstances, should have strengthened, instead of weakened, him.

In commenting on these operations of Moreau, General Hamley says:—

"The false attacks of Ste. Suzanne and St. Cyr had the effect not only of detaining Kienmayer's sixteen thousand men in the defiles, but of causing Kray to move thither six or seven thousand additional troops. But they had no influence in detaining Starray, who was already so distant on the right that it would be impossible for him in any case to join Kray in time for the first operations. We find, then, that at first forty-nine thousand French were employed in detaining less than half their number; and when St. Cyr had joined the reserve, still Ste. Suzanne did not probably neutralise a greater number of the enemy than his own corps. The detached operations of Ste. Suzanne appear, therefore, dangerous and fruitless."

Consider now the plan of Bonaparte. It is evident that the line of the Rhine from Strasburg to Lake Constance would have screened the French corps during their concentration. Since this unfordable river and the bridges crossing it were in possession of the French, there was little probability that the French corps would have been attacked in flank during their march up the Rhine to Schaffhausen. In fact, the Rhine and the mountains of the Black Forest, behind which the greater part of the Austrians lay, would have formed such a complete screen to the operations of Bonaparte that it is not improbable to suppose that the proposed French concentration, preparatory to crossing the river, might have been completed before Kray discovered what was in progress. Moreover, since this plan involved no complicated manœuvres, it could have been carried out more quickly than the plan of Moreau. Thus time would have been saved; and time was then of the greatest importance to Bonaparte, inasmuch as Masséna was in desperate straits at Genoa.

The same reason makes it probable that the passage of the river at Schaffhausen, the most difficult problem of Bonaparte's plan of campaign, might have been accomplished before Kray learned the designs of his adversary. Another fact confirms this view. It will be remembered that, after Moreau crossed the Rhine with his four corps, twenty-six thousand French soldiers still remained in Switzerland and in the French fortresses along the Rhine. Inasmuch as a part of this force was occupying Strasburg, it is quite probable that, had Bonaparte's plan been adopted, a division of four or five thousand men would have issued from the bridge-head opposite this place, and have attacked the Austrians on the west side of the Black Forest. Such an attack would probably have deceived Kray, and have left him in doubt as to where the French intended to cross the river in force; it would probably have caused him to leave Kienmayer's corps in its position, and have prevented him from uniting a sufficient force in the vicinity of Schaffhausen to oppose the passage of the French.

It will be remembered that Bonaparte had already made some preparations for crossing the Rhine near Schaffhausen; he had secretly collected a number of boats on the river between Bâle and Lake Constance. These boats were to be used for the crossing of the advance divisions. The purpose also was to throw two or three bridges across the river; the material for which could have been collected and prepared by Lecourbe's corps while the remaining corps were ascending the Rhine.

It will also be noticed that the point selected by Bonaparte for the crossing was a favorable one. During the passage Lake Constance would have protected the right flank of the French corps from an Austrian attack, and would have continued to protect them as they marched towards Stokach.