Hi Jack
1) Paddy Griffith calculates average ACW firefight ranges at no more than 40 yards, this in accordance with the heavily forested and hilly terrain of eastern North America.
The point is exactly this: no battleground is a flat desk, human eye without binocular help start to distinguish human form at short distances, smoke on the battlefield soon cover the view, weather can add also problem (eyalu was fought in a snow storm) and psycological factors enter in the game. Just before the war british theoricals contested the idea the battle field would become a long range contest, and the successfull french assaults in 1859 reinforced the idea.
) No infantry, charged from flank or rear will withstand any cavalry charge, no matter how weakly delivered. The Square, feelings of support, etc, included, offers no flanks for the enemy to exploit, thus enhancing the feelings of secuirty for the PBIs therein.
Of course, the point is exactly this, the square gives no rear or flanks penalty to the formation so no moral disadvantage, but a cavalry charge given frontally to troops in line well supported on flanks and rear can be repelled as well.
