My essay on Picketing, Skirmishing, and Sharpshooting in the Civil War is up at Essential Civil War Curriculum, a Sesquicentennial project of the Virginia Center for Civil War Studies at Virginia Tech. Primary sponsors are Dr. James I. (Bud) Robertson and Professor William C. (Jack) Davis, both Professors at Virginia Tech.
The security of an army depended on its pickets – the sentinels who provided early warning of infiltration or enemy attack. A picket line is always one of the most picturesque sights in an army, when it runs through woods and fields. You know it consists of a string of ‘posts,’ each of half a dozen men, or so, and, in front of these, a chain of sentries who are constantly on the alert. In the wars of the 19th century pickets and skirmishers had a similar duty – to warn the army of the approach of an enemy and to keep them from observing and interfering with its operations at rest, on the march, or in a battle. In general, the cavalry was responsible for the distant security of the army, with the light infantry doing the close-in work. In practice a skirmish line typically deployed by a regiment was composed of two companies in groups of four comrades in battle, five paces apart with the groups separated by no more than forty. A small body called a support (and in practice usually a company) was positioned about 150 yards behind to fill vacant places, furnish the line with cartridges, relieve the fatigued, and serve as a rallying point. Four hundred yards behind the skirmish line was the reserve, usually formed in close order, upon which the skirmishers could fall back if pressed. In the 19th century the term sharpshooter applied both to precision marksmen (who would be called snipers today) and light infantrymen. When in contact with the enemy the sharpshooters often sheltered themselves in rifle pits. Armed with regular service rifles, repeating rifles or heavy target rifles, both sides concentrated on officers and artillerymen. By mid-war sharpshooters had become an ever-present danger for soldiers everywhere. Although they did not produce the casualties of the clash of the lines of battle, their psychological effect and disruption of the chain of command was palpable. Their victims also included high-ranking officers such as Union Major General John Sedgwick, killed on May 9, 1864, most likely by a sharpshooter armed with a Whitworth rifle; and Confederate Brigadier General George Pierce Doles, felled three weeks later at Cold Harbor by a Yankee bullet.