I've just started reading up on the US Civil War. As I understand it, they started engaging in trench warefare near the end of the civil war because of the dire losses caused on the battlefield by artillery and small arms. Why did Napoleonic era soldiers not employ trench warfare I wonder?

Well, Wellington was a big fan of using reverse slopse on hills, both to portect his troops from unecessary fire and to hide his troop numbers. However....

Agreed. He did try to hide his mass de maneuver.  

Even at their best the rate of fire from cannons was not particularly high, nor was their aiming particularly accurate. recall also that most armies used a majority of solid shot that required a direct hit to be damaging. Colonel Shrapnel had just perfected the shell that would bear his name through the generations, even then his spherical case fragmentation device required great skill to cut the fuse to the correct length for it to explode over the hea dof advancing troops in order to spread the pellets below.

Agreed.  Solid shot still was a US Civil War favorite because the shells were unreliable.

So really, the chief performance meter for napoleonic armies was rate of fire. The French developed the large phalanxed coloumn with supporting horse artillery which they betted could advance on, and break, any two file deep firing line before taking an unnacceptable number of casualties that would force the coloumn back.They were right for the most part.

Battering ram. Originally used because they could not afford the time to train their levees using the Prussian drill. Elan was supposed to make up for volley firepower and the bayonet charge.

At this point the success of British redcoats where others had previously failed becomes apparent. Draconian discipline and hours of drill had combined to produce in the British infantry a formidable firing line. The standard practice was to hold fire until within sixty yards, any further out was useless (as herald states)... other less disciplined European forces would have fired one volley uselessly by this point and would be reloading while the French advanced. Thus the British regiment would make their first volley count, their second volley would be discharged form the second file, and then the real trick of British musketry drill would come into play.... platoon fire. Firing by platoons allowed the British to relaod in quicker times, since they weren't constrained to the average pace of a regiment, or by the slowest man available, it was a less clumsy drill and thus afforded greater speed. As such a redcoat regiment could maintain firing rates of between 4-5 shots to the minute... more than double that of a Spanish regiment (for example).

Yep. They would get off  TWO volleys before the French were on them.

Such a tactic required good judgement and nerves of steels form the commanding officer as well as very tight discipline form the redcoats in order to keep the rate of fire up. At the first signs of French wavering the British line would bayonet charge the French column, which was usually enough to break the will of the column and force the retreat. It was an incredibly succesful tactic. The French army's best hope was always to use it's vastly superior cavalry to push lines into squares, but even then they were rarely succsesful.

 

Maybe because the underrated British artillery and the presence of British sharpshooters (they shot French officers) alos acted as disruptors?

Well, Wellington was a big fan of using reverse slopse on hills, both to portect his troops from unecessary fire and to hide his troop numbers. However....

 

Even at their best the rate of fire from cannons was not particularly high, nor was their aiming particularly accurate. recall also that most armies used a majority of solid shot that required a direct hit to be damaging. Colonel Shrapnel had just perfected the shell that would bear his name through the generations, even then his spherical case fragmentation device required great skill to cut the fuse to the correct length for it to explode over the hea dof advancing troops in order to spread the pellets below.

 

So really, the chief performance meter for napoleonic armies was rate of fire. The French developed the large phalanxed coloumn with supporting horse artillery which they betted could advance on, and break, any two file deep firing line before taking an unnacceptable number of casualties that would force the coloumn back.They were right for the most part.

 

At this point the success of British redcoats where others had previously failed becomes apparent. Draconian discipline and hour of drill had combined to produce in the british infantry a formidable firing line. The standard practice was to hold fire until within sixty yards, any further out was useless (as herald states)... other less disciplined european forces would have fired one volley uselessly by this point and would be reloading while the french advanced. Thus the British regiment would make their first volley count, their second volley would be discharged form the second file, and then the real trick of British musketry drill would come into play.... platoon fire. Firing by platoons allowed the British to relaod in quicker times, sicne they weren't constrained to the average pace of a regiment, or by the slowest man available, it was a less clumsy drill and thus afforded greater speed. As such a redcoat regiment could maintain firing rates of between 4-5 shots to the minute... more than double that of a Spanish regiment (for example).

 

Such a tactic required good judgement and nerves of steels form the commanding officer as well as very tight discipline form the redcoats in order to keep the rate of fire up. At the first signs of French wavering the British line would bayonet charge the french coloumn, which was usually enough to break the will of the coloumn and force the retreat. It was an incredibly succesful tactic. The French army's best hope wa salways to use it's vaslty superior cavalry to push line sinto squares, but even thent ehy were rarely succsesful.

I see. But if you are first to the battlefield, wouldn't it make sense to dig in? I'm also thinking of cannonballs which did horrific damage when they careened thru lines of troops. Having the men in trenches would negate cannonballs completely!

Muzzle loading rifles cannot be reloaded when lying down, so your trenches would have to be at least 4 feet deep, probably 6 feet or more and 4' to 6' wide to accommodate 2 ranks and a firing step.  Thats a lot of earth to move on short notice.

 

Now the cannon balls are ideally, depending on the range, either skipping along the ground or rolling on the ground, so they may well fall in a wide trench anyhow.

 

Lastly, you have immobilized yourself.  Most commanders confronted by an entrenched force in the open would deploy units to keep you pinned in place and send their cavalry and light infantry around your flanks to hit you from behind.  The solution of course is an all around defense, but this only gets you surrounded and besieged.  Armies 'in the field' during that period survived by foraging for food and were seldom more than a couple days away from starvation, so getting surrounded and besieged in the field is a recipe for total defeat.