Artillery Makes More than Just Noise

One of the elements that I don't want to ignore is the effect that artillery had on Waterloo. I think the story doesn't work without all of the elements at work--smoke, confusion, sound, and danger have to be all around.

I think the descriptions of things have to work as well. How would you describe something like this?

Two horses pulling a cannon--a smaller one. Is it a four pounder? An eight pounder? I'm sure that these omissions are fatal in storytelling, but how important are they, really?

Here's a wonderful article about artillery at Waterloo:

During the Waterloo Campaign in 1815 the raising of artillery was beset by some frustrating difficulties, and there was very little time. Napoleon rebuilt the artillery of the Guard but did little to the rest of the artillery. There was no lack of cannons, but trained gunners and horses were in short supply. Despite the poor shape the French artillery still was able to impress even the enemy.

In the beginning of the battle Reille's artillery kept firing on all cylinders and several guns had been brought up as far as the Nivelles Road. Almost all the British eyewitness accounts confirm that the British and German infantry massed on the high ground beyond Hougoumont came under fire and suffered a steady attrition that gradually began to wear on the men's nerves. Most of the British battalions behind Hougoumont-La Haye Sainte line were formed in column of companies (not a "thin red line"). It was a deep formation with all 10 companies lined up one behind the other. It was easy to maneuver battalions so deployed and therefore ideal formation for waiting troops; but it certainly wasn't suitable for withstanding artillery bombardement. 
To lessen their casulaties from artillery fire the British, Dutch and German infantry out on the ground. 
This way Wellington saved many lives. The cavalry in the second line also got under atyillery fire. Sergeant Wheeler of the British 51st Light writes, "A shell now fell into the column of the [British] 15th Hussars and bursted. I saw a sword and scabbard fly out from the column ... grape and shells were dupping about like hell, this was devilish annoying. As we could not see the enemy, although they were giving us a pretty good sprinkling of musketry ..." A British officer wrote that one of the French batteries "was committing great devastation amongst our troops in and near Hougoumont." Bull's howitzer battery also got under fire, suffered losses in men, wagons and horses, and exhausted their own ammunition to such a point that, no more than 2 hours after the beginning of the battle, they were compelled to abandon the line of fire. The fire of the French artillery distracted the British gunners. Instead of targeting the French columns they got involved in counter-battery fire. Wellington had expressely forbade it but it was ignored. (Napoleon explained: "When gunners are under attack from an enemy battery, they can never be made to fire on massed infantry. It's natural cowardice, the violent instinct of self-preservation ...") 
The British artillery was also effective. Some battalions of Reille's corps remained stretched out on the ground in hollows and sunken lanes. Other battalions received the fire standing firm. "Between 2 and 3 PM, a [French] battery drew up on the right side of the buildings and began to bombard them heavily with cannons and howitzers. It did not take long to set them all alight." (- Major Busgen, Nassau Battalion)
Those "sunken lanes" and places where the fighting took place are things that have to be included. I have two short pieces up, and I want to set a goal of solidifying the first few pieces before the month is out. August, being the month of vacation here in Europe, is probably going to be a slow and lazy month if I don't get out ahead of these things.