“On picket on the river bank”

“On picket on the river bank” by Edwin Forbes

“Picket: Soldiers posted on guard ahead of a main force. Pickets included about 40 or 50 men each. Several pickets would form a rough line in front of the main army’s camp. In case of enemy attack, the pickets usually would have time to warn the rest of the force.”

“Glossary of Civil War Terms,” American Battlefied Trust,  ( https://www.battlefields.org/glossary-civil-war-terms#P )
accessed July 22, 2019