The following examples will serve to illustrate the use of different kinds of boat-bridges in military operations:--the passage of the Rhine, in 1702, by Villars; the passage of the Dnieper and the Bog, in 1739, by the Russians; the passage of the Danube, in 1740, by Marshal Saxe; the passage of the Rhine, near Cologne, in 1758, by the Prince of Clermont; the passage of the Rhine, in 1795, by Jourdan; the passage of the Rhine, at Kehl, in 1796, by Moreau; and again the same year, at Weissenthurn, and at Neuwied, by Jourdan; the bridges across the Rhine, at the sieges of Kehl and Huninguen, in 1797; the passage of the Limmat, in 1799, by Massena; the passages of the Mincio, the Adige, the Brenta, the Piava, &c., in 1800; the passages of these rivers again in 1805; the passages of the Narew, in 1807, by the Russians; the several passages of the Danube, in 1809, by the French and Austrian armies; the passages of the Tagus and Douro, in 1810, by the English; the passages of the Niemen, the Dwina, the Moskwa, and the Beresina, in 1812, by the French; and of the great rivers of Germany and France, in 1813 and 1814. A floating body, propelled from one bank to the other by the current of the stream, is termed a _flying-bridge._ The usual mode of establishing a ferry of this kind, is to attach the head of the boat by means of a cable and anchor to some point near the middle of the stream. By steering obliquely to the current, the boat may be made to cross and recross at the same point. A single passage may be made in the same way, by the action of the current without the cable and anchor, but the boat in this case will be carried some distance down the stream. Rowboats are employed for crossing over infantry by successive debarkations; but this process is too slow for the passage of a large force; it may very well be resorted to as auxiliary to other means. Steam craft are so common at the present day on all navigable streams, that an army in the field will frequently be able to avail itself of this means of passing the larger rivers. But, in a hostile country, or in one already passed over by the enemy, it will not be safe to rely with confidence upon obtaining craft of this character. A well-organized army will always carry in its train the means of effecting a certain and speedy passage of all water-courses that may intercept its line of march. Flying-bridges or rowboats were employed in the passage of the Dwina, in 1701, by the Swedes; the passage of the Po, in 1701, by Prince Eugene; the passage of the Rhine, at Huninguen, in 1704; Jourdan's passage of the Rhine in 1795; Moreau's passage in 1796; the sieges of Kehl and Huninguen in 1797; Massena's passage of the Limmat, and Soult's passage of the Linth, in 1799; the passage of the Rhine, at Lucisteig in 1800; the passage of the Po, by the French, just before the battle of Marengo; and others in Italy, Germany, and Spain, in the subsequent campaigns of Napoleon.