Cannonball furnace

One of Napoléon's tasks, when still a lowly artillery officer, was to uprate the defences of the bay of Cannes, by improving the batteries on the Lérins islands. Iron shot was not that dissuasive to naval vessels, whose stout planking meant that, give or take a few decapitated seadogs, the ships suffered relatively light damage. However, the planking was made of wood, which was highly inflammable. Napoléon decided that red hot cannonballs were a serious risk to such ships and commanded the construction of cannonball furnaces, still visible at the batteries, which could heat up the projectiles to incandescence in just a few minutes, though getting the fires to the right temperature first must have taken a while.

Hard to imagine standing below decks on a tinder-box, crowded man-of war, with powderkegs and magazines under your feet, waiting for that red-hot whizz, the hornet's nest of wood splinters, and the smell of burning. However, the imagined appearance of the cannonballs can be judged by the fantastic sight of the dawn over the sea here, as the fiery orb of the sun comes whistling over the horizon and turns the palm trees instantly aflame