Thanks again! This is very helpful. Would there have been a better way to form the troops than to "hold them en masse, so as to charge in column" ?
That is not a specific enough description (in military jargon) to know exactly how they were being held.
Generally, infantry in that day would be deployed in one of the first three formations below:
- Line (wide-front, thin-depth -- two-men-deep in the ACW; Napoleonic Wars were generally three-deep with the British using two-deep; early periods had more). Intended to maximize firepower to the front but very vulnerable to attack from the flank (a line of 500 rifles can fire all of them forward, but only a few to the left or right). Slower to move than a column, harder to maneuver in a different direction.
- Column (narrower-front, thick-deep -- maybe 4-to-30 wide depending on circumstances and use). Good for rapid movement and command control, limited in firepower but can be intimidating/overwhelming in an assault -- very vulnerable if exposed to firepower for long.
- Skirmish (loose formation where men operate individually or in small groups, usually out in front of the main line or in difficult terrain)
- Squares were becoming obsolete after the Napoleonic Wars and were rarely seen in the ACW (Sherman at the Bull Run retreat, Confederates maybe twice at Gettysburg, probably a handful more in the war) and were intended to defend against cavalry attack. Slow moving and dense, they made big targets and firepower doomed them as technology improved (percussion caps, rifles, artillery advancements)
In the description of what Schurz wanted ("hold them
en masse, so as to charge in column"),
en masse probably just means he wants them held at a single location in rear of his main line of resistance. He wants them there so they will immediately available when he needs them, located so they can quickly move to any part of his line (or to his flank) as needed. They would probably not be held in column -- they would be allowed to fall out of ranks as long as they could fall back in as soon as an order was given. If the enemy was not present (not attacking the line seriously, bombarding it, etc.), they might be making coffee and simply waiting.
Once the fighting began in earnest and an order was received, they might be called into column. Their colonels would not have wanted them standing in column until they expected a movement order; they also would not have wanted them straying about since they might be needed at any time.
The part about Schurz wanting "to charge in column" from Howard is subject to interpretation and debate. Schurz had experience fighting in the Revolution of 1848, particularly with the revolutionary army in the Palatinate and Baden fighting against the Prussian Army during 1849. He was part of a group that fled to America in the aftermath and became a force in the Republican Party (Sigel, Schimmelfennig, Blenker, Fritz Anneke and family, etc.). He might have had a very traditional European military meaning for that phrase.
If Schurz really wanted "to charge in column", that would imply he was looking to fight a defensive-offensive struggle, where he would use those 3 regiments to attack enemy penetrations and recover the line or to "sweep the front" (attack at a crucial moment by sallying from the line, pivoting at a 90 degree angle to hit a portion of the enemy from the flank, throwing them into a panic or disarray, driving them back to relieve the pressure, and then returning to the safety of your own lines).
If the word "charge" in the description is really Howard's and not Schurz's, maybe Schurz simply meant that he wanted them
to move in column to whatever point was necessary. Troops move much faster in column than in line, they can change direction easier and faster. They can, if necessary, deploy fairly quickly from column into line when they get to the critical point. Once they get there, they can attack or defend, and they don't have to "charge" if that is a bad idea.
So the "charge in column" part could mean different things. If we knew Schurz actually did intend, say, to use the bayonet that would be a big indicator of what was going on. OTOH, if the "charge" part is simply Howard not getting/not understanding what Schurz intended (or trying to paint a particular slant in the aftermath), Schurz might be simply planning to hold a reserve where he could make efficient use of it -- however it was needed.
Also -- Schurz does not have to use all three regiments in the same moment. By having them in a central spot, he can order them to different points individually if he wants.