James Anson Farrer, Military Manners and Customs
“ But it is the long hours of sentry duty, popularly called ‘Sentry-go,’ which constitute the soldier’s greatest bane. Guard duty in England, recurring at short periods, lasts a whole day and night, every four hours of the twenty-four being spent in full accoutrements in the guard-room, and every intervening two hours on active sentry, thus making in all—sixteen hours in the guard-room, and eight on the sentry post. ”
