Another one would be discipline. The first king/general/commander that came up with having troops moving in unison and doing what they were told in the heat of battle, and got his troops to accept it, was a genius pure and simple. Before that happened all you had were armed mobs bashing at each other in what would've been something little better than a free-for-all.
A few nobody has mentioned: The sturrip Radio Canned and preserved food Interchangable parts Codified drill and organization Clocks Optics like telescopes internal combustion engine electricity and the electric light Refrigeration
Beer or Ale on would not spoil as quickly, when stored, as the water would. The other benefit would be the vitamins that the beer or ale contained wich help stave off scurvy. I think Napolean had Ale with him on his march to Moscow. "A pint a day keeps the scurvy away"
the old guard had scurvy? frostbite surely which leads to the old best invention of all...dms boot mark one..ankle if your a yank and rayburns if your an american air jockey to prevent snow blindness.
Beer staves off scurvy? Jeez, maybe that's why I never had scurvy. I always knew it was good for you....
I bought my son a 10/22 one year for Christmas; he was disappointed that it didn't come with a bayonet, it brought a tear to my eye. A rifle without a bayonet is just a hat rack
Here's my top choices: The Maxim Gun The Percussion Cap Smokeless Gunpowder (Ballastite) Breech-Loading Artillery Rifling