How were pickets (i.e., guards/watchmen/scouts deployed at a distance from the main body of troops) used by the military in the past? How far out would they have been deployed? How were they to signal back to the main force if they found something? Etc. I’m just looking for some general references–I can’t find much online beside the extremely brief Wiki entry.
Well, for one, Pickett’s should never charge.
I guess the idea is they would give a warning in time so the camp could be roused and ready before being overrun… thus discouraging any attempt as futile. How far away does someone need to be, to give enough warning to rouse a sleeping soldier before a person on foot arrives? On horse? (A few hundred feet?)
This would vary greatly through the ages and different armies of course, but one of the main jobs for light cavalry throughout history would have been to provide screens for armies on the march, both ahead (as in scouts) as well as on the flanks to prevent ambush (outriders).
Such units would generally operate in detachments which allowed the local commander to dispatch a fast horseman or two to be sent back to the main body of the army to give warning if enemies were discovered (ideally without the pickets themselves being seen)…
The armies of the 16-17thcentury onwards would deploy some troops in loose formation ahead of, and in rough/forest terrain on the flanks. A musket shot could then be used in an emergency to warn the main body of an impending ambush.
The Roman Army would famously erect a fenced camp each night while on the move to protect against night ambushes, in those cases pickets would simply be posted on the walls.
In accounts of battles such as Shiloh, in the American Civil War, the phrase is often used, “Driving in the pickets,” i.e., attacking so swiftly, so fiercely, that the pickets are simply overwhelmed and general surprise is achieved.
A kind of “inverse square law” applies: the farther out you post them, the more of them you need. You could have perfect security by deploying your entire army in the form of pickets!
(“I thought you said ‘Ricketts.’ Never mind!”)
In Ambrose Bierce’s (excellent) Civil War stories, he specifies that they were to fire once and run back into camp (and hope not to be shot by their own side)
In The Red Badge of Courage, Audie Murphy is warned by his opposite number (Pat Butram, “Mr Haney” from Green Acres) to get out of the moonlight so he won’t have to shoot him.
In The Thin Red Line, James Jones noted the stupidity of retaining the infantry patrol equivalent of cavalry outriders in 20th C. war, since they only give hidden enemy machine gunners advance notice.