Upvote:2
From what I learned in military strategy classes in OCS, the line infantry for pretty much all militaries in the 18th and 19th centuries consisted primarily of ill-equipped, poorly trained conscripts. These were men who either chose the military rather than going to prison, or enlisted because there was no other job to be had. Either way, the one thing they all had in common was that they were expendable.
In those days, it was typical to send in a line of infantry to test the strengths and weaknesses of your enemy. Since these foot soldiers were expendable anyway, you could march them out to see where the enemy had their cannons placed and to see what kinds of weapons they might have available. It also helped to reveal certain formations that may not have been obvious. It also sometimes served to give you an idea as to how motivated or experienced your enemy might be.
In some militaries, they had such overwhelming quantities of line infantrymen that they could simply use them to overrun enemy emplacements. Once they had managed to break through the opposing lines, the better trained troops and/or cavalry would follow them through and engage the enemy's more elite troops.
(If you ever wondered where the term "cannon fodder" came from, it was these types of front line troops.)
Upvote:13
Any unit required to execute formed battle-field drill is likely to size-off regularly in order to place the smaller men in the middle of the line, and the larger men on both wings. This is done in order to minimize unit disruption while wheeling in either direction.
The modern means of sizing off is to:
Unless one was vey near the either end of the line, and knew whether it was a odd=man forward or an odd-man backward day, one couldn't effectively or reliably maneuver onself into the second line instead of the first.
The Canadian Forces Drill Manual describes more elegant means of sizing off on pages 2-26 to 2-29, including the technique illustrated below from a single rank in which the tallest individuals have formed to the right and the shortest to the left:
Interestingly, according to this 1803 British Volunteer Cavalry drill manual cavalry preferred to put the taller mounted-riders in the centre, with the shorter on the wings. This reversal may be favoured by cavalry because the rider not the horse determines the overall height, and thus the horses carrying the lesser weight perform the speedup on wheeling.