Forming troops into lines provided other benefits to an army’s commanders besides massing the soldiers’ fire. Before the advent of radio, commands could only travel as far as soldiers could hear them: officers indicated their instructions (when to march, when to load their muskets, where to direct their fire, and when to charge the enemy or retreat) with a combination of shouts, drumbeats, and musical cues. Keeping soldiers close together helped facilitate those aural commands.
Perhaps most importantly, massing soldiers into tightly-packed formation helped the officers keep a careful watch over their troops, and threaten those whose nerve appeared to waver in the heat of battle. Specially-chosen soldiers stood watch at the end of each line, monitoring their troops’ behavior and standing ready to punish those who fled.
Threats from one’s own commanders proved crucial to keeping troops focused amidst the terror of battle. As the 19th-century Prussian general Frederick the Great put it, an effective infantryman had to be more afraid of his own officers than of the enemy.
“Washington Takes Command of the American Army at Cambridge, Mass., 1775,” Lithograph by Currier and Ives, 1876, ARC Identifier 532915, Series created by the George Washington Bicentennial Commission, U.S. National Archives and Records Administration (accessed September 6, 2012).