In a company, for example, a platoon is sufficient to fulfill, within certain limits, all the functions of a reserve, while in a larger force the duties of a reserve are so complex that each task (protecting the flanks, reinforcing the firing line, giving the impetus for the assault, and covering the assembling and re-forming of the attacking force) must be assigned to a separate unit. Moreover, the duration of a combat, and, in conjunction therewith, the necessity of reinforcing the firing line and covering the flanks, increases with the size of the force. During protracted periods of peace, one is too much inclined to underestimate the wastefulness of a battle and the necessity for reinforcing the fighting line; one cannot understand why 5 to 6 men will not suffice, during the course of a combat, for a front wherein only one man can use his rifle. From the foregoing it follows that the frontage does not increase in proportion to the number of men. Thus, an army corps would not occupy a front four times that of a brigade, or twice that of a division. This is best illustrated by doubling or trebling a plane area when both length and breadth have to be equally increased.[242] [242] See _Taktik_, V, p. 46, et seq. The maximum frontage to be covered in attack by the firing line of a =company= is fixed at 150 m., in order that the density and fire power of that line may be constantly maintained during a prolonged and costly action. During shorter (_i.e._, rear guard actions), or less costly actions (defense), it is, however, permissible to exceed this limit. The regulations by no means insist upon a literal interpretation of this paragraph, since they mention the deployment of the entire company, when it would certainly occupy a front of about 200 m. There is no disguising the fact, however, that, when extended on a front of 200 m., it is out of the question for the company commander to lead his men. The regulations do not fix the combat frontage of a =battalion=, as it depends upon the tactical situation, and the battalion commander is at liberty to place one, two, three, or four companies into the first line. The frontage of a battalion would thus be 300 meters when making an independent attack, and not exceeding 600 meters when fighting a purely defensive action as part of a larger force, in other words, a mean frontage of 400 meters. This is also true of the =regiment=. The combat frontage of a regiment acting alone, will, at the start, seldom exceed that of two battalions deployed abreast. From this we obtain a frontage of 600-800 m. for the regiment when it is acting independently, and a frontage of about 1200 m. when it is fighting a purely defensive action as part of a larger force.