The Spore Powder Behind a Fire-Breather's Flash

Circus and sideshow performers who breathe fire for a living rely on more than showmanship: many of their most dramatic flashes come from a fine, pale-yellow powder pressed from the spores of Lycopodium clavatum, a clubmoss unrelated to true mosses. The spores are tiny and coated in a waxy, oil-rich layer, but that alone doesn't make the powder explosive. Piled together, a flame touched to the heap barely spreads, since only the surface grains reach any oxygen. The trick lies entirely in dispersal: blown through an open flame, the spores scatter into a fine cloud, and suddenly nearly every particle's surface is exposed to enough oxygen to ignite almost at once. That same principle, sometimes described as a controlled dust explosion, once powered stranger machines than a stage act. In 1807, the Niépce brothers burned a mixture of lycopodium powder, coal dust, and resin inside an early internal-combustion engine, using that same oxygen-fed combustion to drive a boat upstream on the Saône. A century later, in 1938, Chester Carlson and Otto Kornei dusted it onto an electrostatically charged plate, and the fine grains clung only to the charged regions of an image, producing the world's first photocopy. A stage flash, a boat engine, and a photocopier turn out to share exactly one underlying mechanism.