Like the smoke grenade posted yesterday, this one was retrieved from Antarctica's Dry Valleys where it was probably used for signaling purposes. Unlike the burning-type grenade however, this bursting-type model used white phosphorus (WP) filler, spread by explosive action. WP is a highly efficient smoke-producing agent, burning quickly at 5000°F upon exposure to air, producing an instant bank of dense white smoke. The intense heat generated by this process causes the smoke to rise rapidly in cold environments, ideal for ground-to-air signaling in Antarctica. Big thanks to Chris Gardner who found and donated both grenades to the Long View Project in the course of his McMurdo Dry Valleys LTER field work. His Antarctic photos are great favorites of mine; I particularly like this Abstract McMurdo set.