TACTICS OF THE LEGION.
§ 54. The tactics of a body of troops consists of their arrangement for battle and their movements in the fight, their order of march, their disposition in camp, and all evolutions in passing from one of these forms to another. The order of battle is chiefly important, because all the other formations are made with reference to this: and to understand the order of battle of any organized body of soldiers, we must first of all study the arrangement of the tactical unit of that body.
§ 55. We must explain a few military terms in common use.
A tactical unit is a body, of a number of which a larger body is composed, and which, in relation to that larger body, is thought of as undivided. The tactical unit of the legion was the cohort; of the cohort, the maniple, etc.
A body of troops is in line when the greatest extent of the body is at right angles to the direction in which they are facing (Fig. 18); in column, when the greatest extent of the body is in the direction in which they are facing (Fig. 21).
Troops are said to deploy when they pass from column to line, retaining the same facing. In Figure 20, the cohort is marching in column. If they simply halt and face to the left, they are in line of battle, as in Figure 18. This they have done without deploying.
Alignment is making a line of troops straight.
A soldier is said to face when, standing still, he merely turns on his heel (to the right, or left, or entirely about).
Fascines are bundles of brush bound together. They are often used for filling a ditch.