>>36590
>potassium
Pot-ash-ium. Mysterious English language. Why not just call it kalium as normal people do?

>charcoal heap
Well, they shoved a pole into the ground, as the center of the pile (it also served to measure the height) and they made a nest at the base of it for the fire. They piled the wood around, larger logs in the center and smaller ones outside. They also left a chimney in the middle I think, but for sure they made a narrow tunnel on ground level where they pushed a pole to the center with flames on it to start the fire. I'm not sure how this "match" was prepared, if it had open flame (let's say was tarred or something), or just kept tip in fire and used the hot coal on it. They built "shelves" around, put short logs around the perimeter, and laid logs/branches on them, and then covered the mound with earth I think (this part I can't recall well) using these "shelves" running around as support, leaving the ground level open so air could be sucked in. Then when they judged it enough, they covered that level too, to slow down the burn, and just let the heat charring the wood over.
The piles were over a man height, and maybe 5 ms in diameter (not sure). I think such pile burned for days.
I remember the burners were covered in soot (like blackface, kek), and smoke covered half the valley.
I assume you have to be excellent making a nest, since if you fuck up, and you can't ignite the fire, you have to tear down half the fucking pile, to redo it.