In my Custer/Spencer/Wilder post I said "They might have changed the outcome of the battle if Charles Dana (Assistant Secretary of War) hadn't came along... "

I need to backtrack/cover my ass on that statement.

I don't think a single brigade, even armed with repeating rifles, could have stopped Longstreet's breakthrough. Massed artillery might have, but it's hard to say because the ground is so broken in that area.

Anyway, about Charles Dana. He was the Assistant Secretary of War under Stanton. Stanton didn't have much use for Rosecrans (Commander of the Army of the Cumberland) and had sent Dana down there to (for all intents and purposes) spy on Rosecrans.

When Longstreet broke through, Dana evidently got seperated from Rosecrans. When he came upon Wilder's men (pretty much the only organized Union troops south of Snodgrass) he commandeered them to escort him to Chattanooga. Wilder was trying to work his way north to support Thomas on Snodgrass at the time, but Dana demanded that Colonel Wilder escort him to Chattanooga.

Whether or not Wilder would have made that much of a difference is a good question. Confederate causalties would have certainly been worse and having a organized body of mounted troops (I have no idea where the Cavalry brigades were at this time. Something for me to research) would have probably made Thomas's withdrawl much easier.