(1) Various reflecting surfaces were used: polished metallic rocks such as obsidian, pyrite, and iron; rock crystal; and an alloy of rose copper and tin, plus an alchemical brew consisting of white arsenic, red tartar, and nitre .

(2) The German U-boats were shooting on the boats, so most of the niter they were trying to import to make nitroglycerin was at the bottom of the ocean.

(3) The fresh juice supplying 30 percent potassium and the mucilage a good amount of niter and sodium.

(4) Nitre, or niter , is also used to manufacture gunpowder.

(5) Maybe Boone noticed crystals of potassium nitrate there, because the deep, loose floor was soon being mined for niter to make gunpowder.