moves steadily forward, and, when it has passed sufficiently far, the detachment leaves the position it had held, and retires rapidly, taking, if necessary, a direction different from that of the main column, and subsequently rejoining it by a détour. The enemy will not follow it very far, as he exposes his own flank to the troops which have already passed.

In flank marches, it is particularly necessary to have accurate information as to the character of the road, and the obstacles to be surmounted, for the least delay might prove fatal, if unexpected. If a defile is to be passed, troops should be sent forward to hold it.

If the flank march is to be executed by a large body of troops, several columns should be formed, if the ground is of a nature to allow them to move freely. The column at the greatest distance from the enemy should be also farthest to the front, the others being thrown back in echelon so as to afford mutual support. If the enemy attacks the first column, he is liable to a flank attack from the others; if he attacks the last column, those in front are in close supporting distance for it.

In Figure 9, M M represents the enemy in position; A is the flanking detachment; B, C, and D the three columns into which the mass to be moved is divided. The columns are moving left in front, so that by simply wheeling to the right, line of battle is formed in echelon towards the enemy. The baggage E may follow the same road as D, or a still more distant one,

the field of battle; but in later years, when armies are moved with so much more rapidity and ease, it is seldom done. However, Napoleon had several roads cut out of the rocky banks of the Saale, in the night preceding the famous battle of Jéna. It might be done again when necessary."

It was the habit of Frederick the Great, when his enemy was incapable of rapid manoeuvres, to fall upon him by a flank march. He formed his own army on such occasions in two columns of companies, so that by wheeling to the right or left he at once formed line of battle facing the enemy. For this purpose, he changed the direction of his march when near the enemy, under cover of some inequality of ground and protected by the advanced guard. These long columns ran the risk of being attacked in front, and often would have been if the enemy had been more prompt, but Frederick knew with whom he had to do. Sometimes, to remedy this grave objection, he moved forward in four columns, and upon changing direction formed two which could wheel at once into a double line, constituting his line of battle. See Figure 10. The two central columns A and A are composed entirely of infantry; one-half of each goes into the front line, and the other half into the second line. The columns B and C, of cavalry, are also each divided equally between the front and second

* Roads were cut at Cerro Gordo by the Americans under General Scott.

lines of the line of battle, of which they form the wings. An advanced guard D covers the heads of the columns and masks their movements. The rearguard E of the columns, becomes the reserve of the line of battle.

Art. IV.-Marches in Retreat.

A retreat may be simply a retrograde movement of one army before another, without an engagement between them, which demands nothing more than the ordinary precautions for a march; or it may be after a defeat, and the general who conducts such an operation will need all the firmness and experience of the finished soldier. The essential thing in a retreat is to get the start of the pursuing eneiny and shake him

off. Forced marches become necessary, and they must often be made at night. Night marches are not objectionable in such circumstances, as there is little or no danger of the retreating army falling into an ambuscade. On the other hand, the pursuing army has that danger to apprehend, and must be proportionally circumspect. The necessary inconveniences and fatigue accompanying night marches must be expected and endured, for safety has become the paramount consideration. Marshal Turenne, after his defeat at Marienthal, held his ground until night, and then took advantage of the darkness to move off, completely distancing the Imperial troops, who dreaded an ambuscade and preferred to wait for daylight. Sometimes a movement to the rear may be concealed from the enemy by lighting the camp fires as if to spend the night, and leaving a few men to keep them burning, while the army passes off quietly. The detachments thus left behind may set off just before daylight and readily rejoin the main body.

When a start is gained in this way, it is important to keep it, even at the sacrifice of some of the wagons that move too slowly. In such times the safety of the troops is the important thing. Every thing, however, should be carried off that can be, and especially the artillery should be saved.

As soon as the commander has determined to retreat, he should order the officer having charge of the train of wagons to move off at once on the route in